Begg Articals Collection

Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1969 Jun (122 - 141): An evaluation of the Begg technique - Swain and Ackerman --------------------------------

An evaluation of the Begg technique Brainerd F. Swain and James L. Ackerman Morristown, N.J. One of the problems in writing a critical analysis of a clinical technique that is named for its originator lies in separating the originator's actual contributions from the specific technique as it later evolved. With the passage of time, we often gain this perspective. Angle, for example, in his latter years, was known primarily for his edgewise arch mechanism and its application to nonextraction treatment. Today, however, both the mechanism and the mode of treatment have undergone extensive modification, and few orthodontists still employ the edgewise arch as Angle did when he introduced it in 1925. Begg introduced a technique, and it, too, has undergone modification, most of the changes being introduced by Begg himself. Like Angle, he also has been concerned not only with tooth-movement objectives but with both the design and metallurgy of the appliance components.2 His collaboration in producing an arch-wire material that combines the mutually antagonistic properties of low stiffness and high resiliency is of special significance, for this wire permits the orthodontist to distribute force at optimal levels for lengthy periods but with less drop in intensity over a wide range of movement and, consequently, with less need for frequent readjustment. Furthermore, he devised a concept about optimal force levels and efficient force distribution, using his wire for arches as well as auxiliaries with a modification of Angle's ribbon arch bracket, and called it "the light wire differential force technique."3,4 This technique has had a broad appeal because, among other things, it provides a rapprochement for the labiolingual and Johnson adherents, who have long favored "light continuous forces," and the edgewise adherents, who have long believed in full-banded appliances and precise control of individual tooth movements. Begg also made his exhaustive study of Stone Age man's dentition, both on living aborigines and on fossil remains, and from it derived his concept of attritional occlusion as the only true anatomic occlusion. From the clinical standpoint, his concept of attrition as a normal physiologic phenomenon which is missing in civilized man provides a scientific rationale for extraction as the only practical alternative to the generalized interproximal wear which is inherent in attritional occlusion. Incidental but worth noting is the fact that less emphasis had been placed on the advisability of occlusal grinding as the analog to occlusal wear that occurs in attritional occlusion. Treatment objectives and the three stages of treatment The general objective of orthodontic treatment with any technique is to obtain a result that simulates normal occlusion in so far as practicable with the malocclusion at hand and the appliance employed for its correction. With the Begg technique, although all individual and group tooth movements toward this over-all objective are carried out simultaneously and as promptly as possible, the treatment is divided into three stages, each of which has its own integrant objectives and movements. In the first stage, the anterior teeth are aligned and their crowns are tipped posteriorly until they meet in an edge-to-edge or slight open-bite relationship. Overcorrection, including overrotation, is done as indicated. The molars are held upright, and Class II or Class III relationships are corrected to Class I or slightly overcorrected. In the second stage, posterior tipping of the anterior teeth is continued and the molar relationships are maintained or overcorrected until all spaces are closed. In the third stage, all teeth which have been tipped lingually or distally during the first two stages, and also any teeth which may have been tipped forward, such as the second 1

premolars in a first-premolar-extraction case, are torqued and paralleled to upright positions. Many orthodontists employ a fourth or finishing stage to improve individual tooth positions before removing the fixed appliances. Differential force: The role of force, resistance, and time in differential tooth movement To understand differential force as it has been employed by Begg since 1961, it is essential to understand biomechanical principles involving force, resistance, and time. 1. In an interdental force system (one that uses no auxiliaries, such as headgear and bite plates) the only appliance forces are those exerted between one or more teeth and one or more other teeth. In keeping with Newton's third law, these forces can only be equal and opposite. They are differential only in that they are exerted in opposite directions. 2. When these forces are exerted, they encounter tissue resistance, and it is tissue resistance that exhibits the differential response to equal and opposite forces which results in differential tooth movement. Simple crown tipping, for example, encounters little resistance and responds rapidly, but root tipping or bodily movement meets with high resistance and responds slowly. 3. In the first two stages of treatment, Begg uses the principle of differential resistance when he opposes crown tipping and other low-resistance, rapid-response movements of the anterior teeth against bodily or high-resistance, slowresponse movement of the anchor molars. This manipulates force and time to conserve anchorage because (a) the light force (about 2 to 2½ ounces) is adequate to overcome the low resistance of the anterior teeth but is less effective against the high resistance of the molars and (b) within this time period (about 10 to 12 months) more of the rapidly responding anterior tooth movements will occur than the slowly responding movements of the anchor molars. Since the first two stages require about half the total treatment time, this means that the period of maximum strain on anchorage is cut in half. The interrelation of force and time has been noted by Ackerman and associates,5 who found that ". . . duration of pressure application was a more important factor in regard to bone resorption than was the amount of pressure applied." 4. In the third stage, Begg uses equivalent resistance when he opposes the high-resistance, slow-response movements of anterior torquing and paralleling against the high-resistance, slow-response movements of the second premolars and molars. However, although the resistances and responses are equivalent in type, they are seldom equal in magnitude, and it is in this third stage that most anchorage loss occurs. In recognition of this, Begg advocates that the dental arches be "too far back" at the end of the second stage, so that the ensuing forward movement during the third stage will not cause the teeth to be too far forward. 5. It would be difficult to overstate the importance of differential resistance to anchorage conservation. Nowhere is this more vividly illustrated than in the contrast between the single-stage, bodily-movement technique described by Begg3,4,6 in 1954 and 1956 and the three-stage, tipping-then-uprighting technique described in 1961. In the earlier technique, he notes that "to insure that the four upper and lower incisor teeth move back bodily, an arch wire with the previously mentioned vertical arch spurs . . . must be used. Also, horizontal band spurs . . . must be soldered to the canine bands, distal to the brackets, to prevent the canines from just tipping back."7 By 1961 Begg had changed the anterior tooth movements of the first two stages, so that "The crowns of anterior teeth are allowed to tip back instead of being moved back bodily because their bodily movement would so strain the molar anchorage that the molar would be moved too far mesially."8 The resulting improvement in anchorage conservation may also be reflected in the fact that in 1954 and 1956 he often spoke of eight-tooth extraction cases but in 1961 noted that these were only about "three per cent of the cases requiring extraction treatment."9 In discussing differential force, Begg frequently cites Storey and Smith.4,10,11 Their findings were obtained with bodily tooth movement and thus were analogous to the Begg technique prior to 1961. However, when Begg adopted the principle of differential resistance for tooth movement in the first two stages, he took advantage of the significant 2

difference between the types of resistance used and the amounts of force required to overcome them. For example, Begg noted that Storey and Smith used 150 to 200 grams (5.3 to 7.1 ounces) of space-closing force on each canine to retract it bodily.12 He found ". . . this force need not be increased proportionally, and perhaps not at all . . ." for simultaneously retracting all six anterior teeth bodily.13 In 1961, however, he stated that only 60 to 70 grams (2.1 to 2.5 ounces) was required on each side to tip all six anterior teeth posteriorly.14 Thus, by employing differential resistance instead of equivalent resistance in the first two stages, he tips all six anterior teeth backward with only 37 per cent of the force Storey and Smith needed to retract the two canines bodily. Furthermore, 60 to 70 grams is only about 20 to 23 per cent of the 300 grams of force reported by them as the minimal required for mesial molar movements. To sum up, in an interdental force system where forces are exerted only between one or more teeth and one or more other teeth, in keeping with Newton's third law, these forces can only be equal and opposite. To our knowledge, Begg has never indicated that the forces used by him were anything but equal and opposite, and the foregoing discussion is not meant to take issue with his concept of differential force. We do suggest, however, that differential force has acquired a broader meaning which may be stated as follows: Differential tooth movement is brought about by the use of differential resistance to equal and opposite forces; equivalent movement is brought about by equivalent resistance to these reciprocal forces. To enhance beneficial movements and to conserve anchorage, differential resistance is used in preference to equivalent resistance as long as practicable during treatment "One-point contact" Differential resistance in practice is more efficient because the crown-tipping and other low-resistance, rapid-response movements of the anterior teeth during the first two stages are enhanced by a free-tipping relationship between the arch wire and bracket, customarily but inaccurately termed "one-point contact." This is best regarded as a pivotal or freetipping relationship that provides both for turning movements and for the force-transmitting relationships variously required in aligning, retracting, and rotating and also for the intrusive and extrusive forces used in overbite and open-bite correction. For each of these movements there must be at least one point of contact between the arch wire and the bracket so that the applied force may be exerted to bring them about. In fact, rotation routinely requires two contacts— one at the bracket and another somewhere on the labial surface of the tooth mesial or distal to the bracket. Since all of the anterior tooth movements just cited are usually required in the first stage, and since they are done concurrently, there are usually four points of contact between the arch wire and the bracket at the same time. Somewhat paradoxically, there are more contact points required for the anterior tooth movements than for the bodily movements of the anchor molars. The round wire in the buccal tube has one point of contact near the mesial end and another at the distal end. Normally, they represent contacts for the anchorage bend forces exerted in the vertical plane but simultaneously may serve for toe-in or toe-out bend force exerted in the horizontal plane. Nonextraction treatment Begg's treatise on Stone Age man's dentition and its implications for frequent resort to extraction in orthodontic treatment have been widely accepted. However, there are two fallacies inherent in any concept that extraction treatment is required for most patients. One fallacy has to do with the possibility that the findings in Stone Age man may not apply with equal force to all races, in every environment, and in various degrees of civilized status. No such sweeping generalization regarding extraction for all cases has been offered but, in the absence of adequate documentation to support this, it should not be assumed. The second fallacy is that, in many practices, there are increasing numbers of patients with mild malocclusions. Furthermore, the mild malocclusions are often milder than those of a few years ago. Extraction treatment is not necessarily inevitable in this group, especially where, in spite of little or no attrition, there is no discrepancy between collective tooth size and arch size. Begg takes note that: "There are Stone Age individuals, just as there are civilized individuals, who have teeth so small and jaws so big that the teeth remain spaced" and, similarly, ". . . textbook normal 3

occlusion can develop only when the amount of tooth substance, relative to jaw size, is so small that attrition is not required to reduce tooth substance.''15 Net distal movement Begg mechanics may be used efficiently in nonextraction treatment and, under certain circumstances, with a greater potential for successful treatment than may exist with other techniques. For example, one of the paradoxical but pleasant surprises of Begg nonextraction mechanics is that anchorage potential is often enhanced if the anchor molars have a mesial axial inclination at the commencement of treatment. This can be exploited through proper manipulation of arch-wire and elastic forces, bone resistance, and elapsed time and may be described as follows: If the anchor molars exhibit a mesial inclination at the commencement of treatment, the combination of normal anchorage-bend force, together with the somewhat lighter Class II elastic force usually employed in nonextraction cases, brings about beneficial distal tipping of the molar crowns into upright positions. In addition, and provided that the Class II elastic force is sufficiently light, the lower as well as the upper molar crowns actually tend to move distally, even though there is no distal force exerted directly on them. This net distal movement occurs because, although the influence of the anchorage bend simultaneously tends to tip the crown back and the root forward, crown tipping is a rapid-response movement while root tipping is a slow-response movement. Therefore, more crown tipping than root tipping occurs within a given time. Net distal movement of mesially inclined anchor molars is another example of differential resistance in action. It is important in nonextraction treatment because it provides more arch length for teeth anterior to these molars. Note that three conditions are required for net distal movement— light force, no molar tieback, and an arch wire that slides freely in the tube. In extraction treatment, the uprighting of the anchor molars is beneficial but the resulting increase in arch length, if any, is transitory because the elastic forces are often greater and are used longer and the concomitant forward movement of anchor molars is normally desirable. Net distal movement of mesially inclined molars resulting in an increase in arch length is effective in nonextraction Begg mechanics because the force of the elastics employed is usually less and the elastics are often used for briefer periods of time, thus reducing any subsequent tendency for the molars to move forward. Mesially inclined molars are not present in all nonextraction cases, just as the criteria required for nonextraction treatment are not present in all cases. Fig. 1 shows a simple test for ascertaining mesial inclination of molars. It is emphasized that Begg mechanics can take advantage of such mesial inclinations of molars because it is inherent in this technique that molars are not tied back to the arch wire and that there is a free sliding relationship of the arch wire in the molar tubes. These relationships combine to permit the low resistance of distal crown tipping to manifest itself before the high resistance of mesial root tipping can occur to any appreciable extent, provided, of course, that any elastic force tending to tip the molar crowns forward is sufficiently light that it is unable to overcome the net distal movement except through extended use, which in nonextraction cases is avoided. Such mechanics are not feasible if the elastic force is too heavy, and in this conjunction it should be noted that net distal movement was seldom observed while the heavy elastics which were in vogue some years ago were being used. When first attached, the measured force of these elastics was seldom less than 5 ounces and ranged as high as 8 ounces. This force usually decreased in the first 48 hours to approximately 2 ounces and remained at or close to this level for the remaining 2 days of the 4-day period in which they were customarily worn. Apparently the higher force present during the first 48 hours inhibited net distal movement of the lower molar crowns. Mesial migration, anchorage loss, and headgear Many orthodontists have come to regard Begg's concept of attritional occlusion and the inherent tendency to mesial migration as a normal physiologic phenomenon with significant implications regarding the need for extractions in orthodontic treatment. In addition, many agree with his thesis that the use of headgear in orthodontics is contraindicated 4

because it arrests normal mesial migration of teeth and thus merely defers future collapse due to the reappearance of mesial migration following removal of the appliances. Mesial migration as a normal physiologic phenomenon should not be confused with mesial movement and, concomitant anchorage loss as a response to orthodontic force, especially where mesial movement due to orthodontic force exceeds that which would occur through mesial migration. To weigh this for its practical application, let us consider the treatment of a maximum anchorage case such as that shown in Figs. 2 and 3. This patient presented with (1) a full Class II relationship of the buccal segments, (2) marked protrusion in combination with (3) crowding of the upper and lower anterior teeth. The profile photograph and the cephalometric analysis reflect the severe anchorage problem. In the discussion of treatment, which was performed by students in the Orthodontic Clinic of Fairleigh Dickinson University, extraction of the four first premolars was recommended and a provisional recommendation was made for extraction of four more teeth and a secondary treatment phase, if such became necessary. Following removal of the four first premolars, conventional Begg mechanics were employed during the first two stages for correction of the Class II relationship in the buccal segments, elimination of overbite and overjet, and closure of all spaces. This was uneventful and routine At the beginning of the third stage, the case was again evaluated regarding the amount of anchorage loss to be anticipated during torquing and paralleling and whether the loss would be so great that removal of four more teeth and a secondary phase of treatment would become necessary. Since the dental arches had been in protrusion from the commencement of treatment, they never had been in a favorable position to sustain any of the characteristic forward movement which occurs in the third stage. Therefore, with the sole objective of reducing such anchorage loss, the patient wore headgear throughout the third stage. This did not move any teeth posteriorly, nor did it entirely prevent forward movement; consequently, it did not operate contrary to the forces of mesial migration. This was done only to conserve the existing positions of the molars in so far as practicable and thus reduce mesial movement due to the orthodontic forces of torquing and paralleling, which is a separate and distinct entity from the normal physiologic forces of mesial migration. The result, in terms of anchorage conservation, may be judged from the photographs of the casts, the face, and the cephalometric analysis. No additional extractions or treatment were indicated. The use of headgear during the third stage of treatment for borderline eight-tooth extraction cases or other maximum anchorage problems does not contravene the normal forces of mesial migration but acts simply to prevent orthodontic forces from causing undue anchorage loss in patients for whom the result would otherwise be a bimaxillary protrusion or a need for four more extractions and additional treatment. Overcorrection Although we present a case illustrating overrotations (Fig. 4), there is little evidence in the form of treated cases presented at meetings and in textbooks or periodicals to indicate that orthodontists have abandoned Angle's objectives in favor of overcorrection. If overcorrection is to acquire any more status in orthodontic practice than that of a fascinating plausibility, then factual evidence should be presented on its behalf. It could be argued that evidence already in existence supports the concept of overcorrection, but evidence should include (1) the malocclusion, (2) the overcorrection, (3) normal occlusion showing the relapse from overcorrection to normal, and (4) a subsequent model showing stability following relapse of the teeth from over correction to normal occlusion. It may be significant, for example, that our patient did not exhibit stability of rotated teeth following relapse from overcorrection to normal (Fig. 4). Analysis of tooth movement in thirty patients The opinions expressed here are based on clinical observations and impressions of patients treated with the Begg technique over the last several years. For purposes of documentation, a study was made on a group of thirty patients treated by Swain. Wherever an opinion is offered in this article, it is in agreement with the evidence derived from these 5

thirty cases. We emphasize that none of the patients in this group have been out of retention for a sufficiently long period of time to warrant conclusions about long-term results. Tooth movement in the occlusal and transverse planes. The goal of orthodontic treatment in the occlusal and transverse planes is the effective handling of tooth-size-to-arch-length discrepancies, alignment of irregular and rotated teeth, and the establishment and maintenance of proper arch width, form, and symmetry. The free tipping relationship of the arch wire and the modified ribbon arch bracket is maintained throughout treatment except for the influence of the auxiliaries used in the third stage. This relationship is advantageous for bringing about the anteroposterior tooth movements required for treating most malocclusions, certainly in extraction cases. This relationship is also helpful for the tooth movements required in the occlusal and transverse planes, but there are some disadvantages, and these are coupled with the fact that although the relationship of the arch wire in the buccal tube effectively controls the axial inclination of the molars in the anteroposterior plane, it does not act so effectively to control lingual or buccal tipping. Lingual tipping, particularly of lower molars, is a common occurrence in the first stage of treatment. It is least noticeable in nonextraction treatment and most noticeable in molar-extraction cases. Buccal tipping, particularly of the upper molars, is often seen in the third stage. There are several ways in which these undesired molar movements can be controlled. Lingual tipping is avoided by incorporating extra width in the arch wire in the molar areas. This is called expansion for prevention, because the additional arch-wire width is only for the purpose of maintaining dental arch width. In addition, Begg employs a double-back arch wire in an oval tube on the anchor molar in secondpremolar and first-molar extraction cases to control lingual tipping. This introduces another application of differential resistance to force which has not been emphasized previously. The doubled-back arch wire can be adjusted so that it exerts a torque force tending to tip the molar roots lingually and the crowns buccally. In practice, the roots do not move lingually but the crowns do tip buccally because root movement in the buccolingual plane is a high-resistance, slow-response movement, just as in the anteroposterior plane, whereas crown movement in the buccolingual plane is a low-resistance, rapid-response movement, just as in the anteroposterior plane. Consequently, although no force is exerted directly on the molars to prevent the crowns from tipping lingually, they will not do so because of the differential in resistance between root and crown movements. An analogy may be detected between the beneficial action of differential resistance in the transverse plane and that of net distal movement of anchor molar crowns in the anteroposterior plane. In each case, the mechanics take advantage of the higher resistance of root movement in order to induce a beneficial movement or to prevent an undesirable movement of the crowns. This is reminiscent of the sport of judo, in which one applies physical force against the opponent's greater strength in order to exploit his weakness. Thus, beneficial crown movements or prevention of detrimental movements through the use of root-tipping forces may logicall!y be called orthodontic judo or judo mechanics, because they are similarly based on principles of leverage and resistance.17 Other examples of judo movements include the use of braking springs on canines (1) to prevent excessive distal tipping, (2) for correction of excessive tipping if it has occurred, (3) for net distal movement of mesially inclined and partially erupted lower second molars, and (4) in the occlusal and transverse planes, the use of a paralleling or uprighting spring near the end of the second stage for tipping anterior crowns mesially or distally in order to correct a midline discrepancy. Finally, judo mechanics are helpful in correcting buccal-segment cross-bites, and this is often done with an auxiliary wire incorporating one or more torque loops resting against crowns that need buccal or lingual tipping. These have been described elsewhere.17 Since there is a free tipping relationship of the brackets and arch wires, the correction of midline discrepancies is often facilitated, especially if it was due to crown tipping. In these cases, as the extraction spaces close and proper arch form and symmetry are attained, midline discrepancies often correct themselves spontaneously without the aid of auxiliary springs. However, if the discrepancy is due to bodily displacement of teeth to the right or to the left, then after the initial tipping of crowns has taken place, paralleling springs must be employed during the third stage to move the roots into 6

upright positions just as they are uprighted in the anteroposterior plane during this stage. This is not a judo movement, since the root-tipping force is used with the intent of moving the roots rather than the crowns. Because the arch wire is relatively thin and has low stiffness but high resiliency, it is very efficient for aligning and rotating irregular teeth. This is done through the incorporation of vertical loops as necessary. Alignment is done rapidly and efficiently, and looped arch wires are frequently replaced by plain arch wires after the first or second appointment. This is done intentionally because plain arch wires are much more efficient for leveling the plane of occlusion, especially that of the anterior teeth, and also for exerting a depressive force on them more evenly. The greater flexibility imparted by the presence of the loops in an arch wire prevents it from being efficient for attainment of arch width and symmetry and also for exerting an even depressive force on the anterior teeth. Because of the light arch wire employed, arch symmetry occasionally is a problem, especially if the patient has undesirable posture habits which result in asymmetrical pressure being placed on the arch wire and on the teeth. These are readily corrected, however, through the employment of compensating asymmetry in the arch wires. Because of the low stiffness of the arch-wire material, arch width has probably received less attention and less emphasis than that given it in other techniques where heavier arch wires are used. As a general rule, an effort is made to retain the width of the arches during treatment unless corrections, as of posterior cross-bites, are required. In such instances, doubled-back arch wires are helpful for correction of molar cross-bites through the use of judo mechanics, but the chief reliance, especially during the first two stages, is placed on the cross-bite elastic, since it exerts six to eight times the expansive or contractile force exerted by the arch wires, even though these may have been expanded or contracted strongly. Arch asymmetries can arise not only from posture habits but as a ramification following the use of vertical loops, offset bends to attain or maintain overcorrections, rotating springs, and elastic thread for rotating purposes during the first two stages. In addition, asymmetries can develop with paralleling and torquing auxiliaries, since these produce some reactionary force in the horizontal plane as well as primary force in the vertical plane. However, if base arch wires 0.020 or 0.022 inch in diameter are used in the third stage, the high stiffness of this wire minimizes these asymmetries. In addition, after removal of the auxiliaries in the fourth or finishing stage, the width, form, and symmetry of the arches can be improved as necessary with finishing arch wires. Finally, any additional changes can be attained through the routine use of tooth positioners following removal of the fixed appliances. The routine use of efficient lingual attachments should be emphasized. For example, correction of premolar and molar rotations can be achieved through the use of buccal and lingual horizontal elastics in various combinations during the second stage. In the third stage, after all teeth are in proximal contact, buccal or lingual elastics can be used to produce buccal or lingual movements of molars as well as rotations. To sum up, despite the free tipping relationship between the arch wire and the bracket, anteroposterior and mesiolateral movement of crowns and roots can be effectively controlled, as can arch form, width, and symmetry. Cephalometric analysis Vertical dimension. The two major goals of orthodontics with regard to the vertical dimension are correction of the anterior overbite relation and prevention of adverse or clockwise rotation of the mandible. One of the unresolved controversies regarding Begg treatment is the manner in which the bite is so effectively opened. Our findings support a contention that overbite correction is done primarily through increased eruption of the mandibular molars. The reason that the term eruption is used here is that in almost all cases the mandibular molars continued to erupt after removal of the appliances. This is another instance in which the term differential is useful, for increased eruption of the molars did not coincide with the eruptive behavior of the lower incisors. They erupted differentially, and this will be described. 7

Although lower incisor depression has been observed, none of the mandibular incisors of these 30 patients was intruded. However, in almost all cases the mandibular incisors did not erupt vertically at all during treatment. Thus, Begg mechanics seem to prevent normal eruption of the mandibular incisors while accelerating eruption of the mandibular molars. In the maxillary arch, eruption of the molars is not as greatly accelerated and, by the same token, normal eruption of the maxillary incisors is not inhibited so effectively as that of the mandibular incisors. If there is a harmonious growth pattern with ample growth increments, it does not seem to be affected by this differential eruption of the molars and incisors with regard to rotation of the mandible (Fig. 5). However, in the cases in which mandibular growth was apparently outstripped by molar eruption, there was a tendency toward clockwise rotation of the mandible (Fig. 6). This acted to open the bite further because of the decrease in the FMIA. In most extraction cases there is some degree of this rotation. On the other hand, no clockwise rotation of the mandible was observed in the nonextraction cases. Perhaps this can be explained by the fact that these patients routinely demonstrated harmonious growth patterns plus good increments of growth during treatment. As a matter of fact, some of them demonstrated counterclockwise rotation of the mandible during and after treatment (Fig. 7). Relapse of overbite correction in extraction cases after treatment was caused by additional eruption of the mandibular incisors. The molars do not intrude during retention but, on the contrary, continue to erupt to some degree. Unfortunately, the mandibular incisors seem to erupt more than the mandibular molars after active treatment, and this results in a deepening of the bite. The maxillary molars and incisors either maintain their vertical positions or continue to erupt synchronously during retention. If adverse rotation of the mandible had taken place during treatment, there was occasionally a significant favorable change in the direction of growth of the mandible during retention. This tends to support the concept that the inherent morphogenetic skeletal pattern is persistent. As orthodontists, we may have a greater potential ability for harnessing tooth eruption than we have for harnessing skeletal growth. It is possible that teeth are more sensitive to stimulation or inhibition of eruption than the bones of the craniofacial complex are to stimulation or inhibition of growth. Perhaps we should look more closely at growth and eruption of the dentition as it relates to treatment mechanics. The important question is whether favorable differential eruption attained during treatment can be maintained after retention. Anteroposterior dimension. The objectives of orthodontic treatment in the anteroposterior dimension are correction of the molar relationship, correction of overjet, and improvement of the profile wherever necessary. One of the goals of Begg treatment in extraction cases is to tip the crowns of the anterior teeth posteriorly and to maintain the anchor molars in an upright position. The maxillary molar is maintained in the same anteroposterior position while the mandibular molar is brought forward to correct the Class II molar relationship, when present. Once the crowns of the maxillary anterior teeth are tipped posteriorly, the roots are then tipped posteriorly to upright these teeth. According to the cephalometric analysis, these desired tooth movements are routine findings in the treated cases. Also, in almost all cases in which a large ANB angle existed prior to treatment, this angle was reduced during treatment. According to the Steiner analysis, this was accomplished by considerable torquing of the maxillary incisors. The mandibular incisors are routinely retracted in extraction cases, according to our analysis. However, retraction of the maxillary teeth is clearly more significant than that of the mandibular incisors. The mandibular incisors are also tipped. The over-all effect with regard to lower incisor retraction is one of translatory movement. Thus, the reduction of the incisor– mandibular plane angle in these cases is misleading since these teeth are retracted with but little change in inclination. 8

Occasionally the maxillary molar does come forward, but this does not always constitute a loss of anchorage, since in some cases this is a desirable movement. The Begg appliance seems to correct the molar relation effectively when necessary; overjet, when present, is significantly reduced, and the profile changes are proportionately good. Our findings confirm previous observations that the greatest amount of anchorage loss occurs in the third stage and that, where there is a great amount of torquing to be done and the duration of the third stage is proportionately increased, there is greater risk of anchorage loss. The posttreatment changes in the anteroposterior dimension are as follows: 1. The acquired Class I molar relationships are stable. 2. The overjet correction is maintained. 3. The position of the entire dentition in relation to the cranial base occasionally shows change. In some cases the entire dentition comes forward en masse through eruption or mesial migration. In the majority of cases, however, the dentition remains in a stable anteroposterior position relative to the cranial base after active treatment. 4. In some cases, as the teeth continue to erupt, the eruptive path of the mandibular incisors in relation to symphysis is upward and backward. Thus, in some of the cases, what appears to be retraction of the mandibular incisors may simply be a manifestation in part of the normal eruptive pattern. In other cases, however, retraction was obviously a result of the mechanics, since after treatment the mandibular incisors seem to erupt upward and forward. If there were some way of predicting the direction of eruption of the incisors in relation to the symphysis, it might be easier to weigh the need for extractions in the so-called borderline case. Finishing treatment In the preceding discussion, emphasis has been directed toward the control of tooth movement, including the conservation of anchorage, in the occlusal, transverse, anteroposterior, and vertical planes. From the standpoint of overall tooth movement, including conservation of anchorage through sole reliance on interdental anchorage, the Begg technique is a precision technique. However, anchorage conservation should not be confused with precise control of individual tooth movements. In this respect, we agree with Begg that "It is possible to obtain more accurate final tooth positions generally and more accurate occlusal relations with tooth positioners than with any other orthodontic appliance now employed."18 This is not to say that one cannot place additional offset bends in arch wires or use additional elastics or elastic thread or rotating, paralleling, or torquing auxiliaries on individual teeth as necessary; rather, from a practical standpoint, the complexity and multiplicity and the chair time required are feasible in theory but not in practice. As a consequence, precise control of individual tooth movements with the free tipping relationship of the wire and bracket often leaves something to be desired in the final result, and this is readily apparent if one compares a group of cases finished with positioners with a group finished without positioners. Treatment time and efficiency Because of the relatively continuous forces exerted by the Begg light wire, tooth movement continues over a long span of time with little drop-off in the amount of force and, consequently, with less frequent need for readjustment. In addition, the level of force is low, and the technique can be said to be relatively painless. A certain amount of tooth mobility is seen, but this seems to be a sequel of any multibanded technique. Root resorption is observed, and in this conjunction we would report that, in a comparison of apical root resorption incident to Begg and edgewise treatment, Bogucki19 studied the pre- and posttreatment full-mouth roentgenograms of thirty Begg and thirty edgewise patients treated by one of us and found no significant difference between the two groups in the amount and distribution of root resorption.

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The incidence of devitalization is very low, probably because of the relatively low level of force exerted throughout treatment and despite the rapidity with which the initial movements take place. The uprighting, paralleling, and detailing movements of the third stage usually require as much time as the first two stages combined. It should be emphasized that although the over-all gross tooth movements are often accomplished rapidly, the attainment of precise individual tooth movements does require additional time and effort. This means that the total treatment time is somewhat less than with other techniques, and, in our case sample, averaged 22 to 24 months with extraction treatment and less with nonextraction. Chair time also is less, and frequently nothing more than an inspection is required to determine that the appliances are in good order and that desirable tooth movements are occurring but undesired changes are not. Consequently, the number of appointments (and therefore the time required for arch-wire changes) is reduced. This corresponds with Barrer's20 findings in his survey of 238 orthodontists using the Begg technique. During the first two stages, the arch wire is only pinned to the anterior teeth; hence, removal, adjustment, and replacement are done promptly. The interval between appointments is usually longer, since readjustment of the appliances is required less often. Conclusion The Begg technique is an evolving technique and has undergone significant development since it was described in 1954. These changes manipulate force, resistance, time, and growth to enhance beneficial movement and inhibit anchorage loss. Concepts relative to these are advanced herein and include differential resistance, equivalent resistance, differential eruption, net distal movement, orthodontic judo, pivotal relationships, and physiologic mesial migration versus orthodontic mesial movement. The Begg technique is an effective mechanotherapy for treatment of malocclusion of the permanent dentition. It accomplishes efficient and predictable correction and anchorage conservation. Its advantages far outweigh its few disadvantages.

10

Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1969 Jun (122 - 141): An evaluation of the Begg technique - Swain and Ackerman. -------------------------------1. Begg, P. R.: Stone Age man's dentition, AM. J. ORTHODONTICS 40: 298, 373, 462, 517, 1954. 2. Begg, P. R.: Stone Age man's dentition, AM. J. ORTHODONTICS 40: 527, 1954. 3. Begg, P. R.: Stone Age man's dentition, AM. J. ORTHODONTICS 40: 517-531, 1954. 4. Begg, P. R.: Differential force in orthodontic treatment, AM. J. ORTHODONTICS 42: 481-510, 1956. 5. Ackerman, J. L., Cohen, J., and Cohen, M. L.: The effects of quantified pressures on bone, AM. J. ORTHODONTICS 52: 34-46, 1966. 6. Begg, P. R.: Light arch wire technique, AM. J. OBTHODONTICS 47: 30-48, 1961. 7. Begg, P. R.: Differential force in orthodontic treatment, AM. J. ORTHODONTICS 42: 492, 1956. 8. Begg, P. R.: Light arch wire technique, AM. J. ORTHODONTICS 47: 38, 1961. 9. Begg, P. R.: Light arch wire technique, AM. J. ORTHODONTICS 47: 35, 1961. 10. Begg, P. R.: Begg orthodontic theory and technique, Philadelphia 1965, W. B. Saunders Company, p. 105. 11. Begg, P. R.: Origin and progress of the light wire differential force technique, Begg J. Orthodont. Theory & Treat. 4: 11, 1968. 12. Storey, E., and Smith, R.: Force in orthodontics and its relation to tooth movement, Australian J. Dent. 56: 13, 1952. 13. Begg, P. R.: Differential force in orthodontic treatment, AM. J. ORTHODONTICS 42: 483, 1956. 14. Begg, P. R.: Light arch wire technique, AM. J. ORTHODONTICS 47: 37, 1961. 11

15. Begg, P. R.: Stone Age man's dentition, AM. J. ORTHODONTICS 40: 311-312, 1954. 16. Begg, P. R.: Begg orthodontic theory and technique, Philadelphia, 1965, W. B. Saunders Company, p. 348. 17. Swain, B. F.: Begg technic. In Graber, T. M. (editor), Current orthodontic concepts and techniques, Philadelphia, 1969, W. B. Saunders Company. 18. Begg, P. R.: Begg orthodontic theory and technique, Philadelphia, 1965, W. B. Saunders Company, p. 352. 19. Bogucki, Z. P.: A comparison of apical root resorption incident to Begg and edgewise orthodontic therapy, Master's thesis, Fairleigh Dickinson University, 1966. 20. Barrer, H. G.: An evaluation of the Begg technique five years later, Begg J. Orthodont. Theory & Treat. 3: 29-34, 1964.

Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1981 Jun (610 - 624): Maxillary anterior intrusive forces generated by Begg Stage I appliances - Thornton and Nikolai

-------------------------------Maxillary anterior intrusive forces generated by Begg Stage I appliances Charles B. Thornton, D.M.D., M.S., and Robert J. Nikolai, Ph.D. St. Louis, Mo. The cpability of Begg mechanotherapy to produce intrusion of the maxillary anterior teeth, particularly the incisors, has been questioned. Although the Stage I appliance opens the bite, this can be the result of one or a combination of several occlusogingival displacements, and the manner of bite opening continues to be a subject of discussion. Support in favor of anterior maxillary intrusion exists, at least in part, because of the potential for extrusion of these teeth during Stage III. However, the magnitudes of actual intrusive force generated by the Begg Stage I appliance apparently have not been investigated heretofore. The purpose of this experimental study was to quantify and compare on the bench the intrusion potentials of maxillary appliances used in Stage I by Begg practitioners. Five independent variables (size of anchor bend and gable bend, Class II elastic-force magnitude, anchor-bend positions, and archwire diameter) and a total of 135 appliance configurations were evaluated. The raw intrusive-force data were reduced and analyzed by means of accepted statistic al procedures. The individual contributions of the independent variables in the appliance were investigated. Parametric relationships, developed within the experimental results, were compared to the predictions of the engineering bending theory for beams and arches. A force analysis of the appliance design was carried out toward evaluation of anchorage potential This investigation revealed that the appliances generate light to moderate intrusive forces, that wire diameter, anchor-bend size, and elastic-force magnitude are the controlling parameters, and that several combinations of` variable values may yield identical intrusive-force magnitudes as activated. For most of the appliance configurations tested, the results were in general agreement with the elastic bending theory. 12

Although intrusive forces generated by the most commonly used Begg appliances were found to be rather light, factors inherent in the design– in particular the nonuniform distribution of the intrusive force throughout the anterior segment– tend to enhance the potential for intrusion. A systematic approach to the fabrication of the appliance is suggested. The capability of generating intrusion of the maxillary incisal segment must be inherent in virtually every type of comprehensive orthodontic mechanotherapy. Intrusion is necessary for proper retraction of the maxillary incisors in many cases. These teeth may often require intrusion, even before retraction, because of anatomic limits of the premaxilla. Esthetic considerations can demand intrusion of the maxillary incisal segment in patients who, prior to orthodontic treatment, present substantial exposure of premaxillary gingiva upon smiling. Maxillary incisor intrusion is a highly desirable result of Stage I of Begg treatment mechanics. A paramount objective of this portion of the treatment is opening of the bite. Intrusion is sought in Stage I because a substantial potential for extrusion of the maxillary incisors exists in Stage III of pure Begg mechanotherapy. Clearly, bite opening can be accomplished through a number of distinct occlusogingival displacements. In examining cases, some clinicians have questioned the actual occurrence of intrusion in Stage I. The issue is clouded by the fact that labiolingual changes in longaxis angulation often accompany the alleged intrusion. Apparently, no previous investigation has been undertaken to actually quantify the force system associated with the activation of the Stage I appliance. The principal objective of this bench-experimental research was to determine the initial magnitudes of intrusive force exerted by the arch on the anterior segment in Stage I mechanics. Also sought were the relative levels of influence of the various appliance parameters on intrusive force. Suggestions of Begg practitioners as to the sizes of Class II forces and second-order bends are discussed in the light of the research results, and a superficial comparison of data obtained with the bending theory of arches is carried out. Previous research The literature contains conflicting accounts describing changes in vertical positions when bite opening takes place in Stage I of Begg therapy. Overbite correction has been reported as resulting from (1) primarily increased eruption of the mandibular molars,1,2 (2) intrusion of the mandibular incisors,3-7 and (3) a combination of mandibular incisor intrusion and mandibular molar extrusion.8-12 To distinguish between the effects of orthodontic treatment and those of growth is difficult; in only one of the studies referenced was the differentiation attempted between the influences of mechanics and vertical dentoalveolar growth.12 Measured changes in the vertical positions of the maxillary incisors during Begg therapy have been included in a number of investigations; a sample is presented in Table I. Because of alterations in longaxis angulations, vertical-position changes in both incisal edges and apices have been reported in several papers.10,13 Kesling felt that ''failure to elongate while being tipped to a more upright position is a sign of actual depression.''16 Of those studies included in Table I, only Rocke15 attempted to isolate the effects of growth; generally, because the duration of Stage I is relatively short, most investigators judged the contribution of growth to be negligible. The differing magnitudes of vertical change reflected in Table I are undoubtedly due in large measure to the variations in execution of the Begg technique. In Stage I, Class II elastics are employed to retract the maxillary incisors. Unfortunately, in addition to the desired distal force component, these elastics exert an extrusive component of force against the segment. The majority of reports in the literature suggest a Class II force of 2.0 to 2.5 ounces,1,2,6,8,18,19 but values as low as 1 ounce2 and as heavy as 4 ounces20 have been advocated. The design of the stage I maxillary arch wire itself is clearly important, and variations therein apparently may produce substantial changes in the intrusive potential of the appliance. Sims21 has suggested that the anchor bend is critical to the design, and he has argued that this bend must be greater than 30 degrees to be effective. Sims22 has also proposed that a gable bend might be placed distal to the canine to increase the intrusive potential. Although forces to intrude maxillary incisors apparently have not been quantified by or for the Begg practitioners, Burstone23 measured in his appliances and proposed use of the following force values: 50 Gm. total against the central 13

incisors, 100 Gm. against the incisal segment, and 200 Gm. against the six-tooth anterior segment. Ricketts and associates24 have suggested that force magnitudes be based upon the projected tooth root area(s) (for intrusion or extrusion, as viewed in the occlusal plane) and an average intensity of force per unit area; their formulation gives 15 to 25 Gm. per incisor and 60 Gm. for an average canine. While Sims21 has presented some data on the maxillary arch wire alone, we found in the literature no previously reported measurements of intrusive force generated by a Begg Stage I arch wire with light Class II elastics. In this article such measurements for a number of Stage I appliance configurations are presented, compared, and discussed. Materials and methods To quantify the intrusive forces which would be exerted against the actual anterior segment, a testing frame was first fabricated to support the maxillary appliance. The basis for the over-all frame design was the first-premolar-extraction case described by Sims.21 To the posterior supports of the frame were cemented buccal tubes and the mandibular molar positions were simulated by inclined slots in the same supports; the slots contained movable attachments, supported the Class II elastics, and permitted adjustments in their force magnitudes. Stops were provided distal to the buccal tubes to sustain the horizontal anteroposterior components of the Class II elastic forces. Interdental dimensions were those of Newman25 and are given in Fig. 1; all maxillary arch wires were formed to trace the occlusal-plane-view guide shown prior to placement of anchor and/or gable bends. In a typical test, the arch wire was initially engaged passively in the buccal tubes. A reading was noted on a vertical ruler, mounted on the frame, in order to check passive conformity of like arches at the midpoint. The arch was then activated toward the occlusal plane via a force gauge, also mounted on the testing frame, to a position all but touching the ends of two screws which simulated the incisor brackets. The force was distributed throughout the anterior segments by means of a jig placed between the arm of the force gauge and the arch wire. While maintaining the position of the anterior portion of the arch wire, the Class II elastics were attached and then activated to the desired force level for the specific test. Finally, the intrusive force was read from the gauge. Force gauges covering a range of 10 to 250 Gm. were employed in over-all testing; readings of 12 Gm. or less were obtained through use of hanging, standard weights. The testing frame, with ruler, force gauge, and an activated appliance, is shown in Fig. 2. Fifteen maxillary arch wire subsamples were chosen for evaluation. Twelve were formed from 0.016-inch (diameter) "Orange Special Plus Australian" orthodontic wire (Group RCW) and three from 0.020-inch (diameter) ''Black Special Australian" wire (Group RLW). The Class II elastics were latex ''Col-R-lastics." wire and elastics were obtained without bias from TP Laboratories of LaPorte, Indiana. All wires were formed by typical, repetitive, clinical bending procedures employing arch-contouring and lightwire pliers. Each arch was shaped and cut to fit the arch-form guide (Fig. 1) and anchor- and gable-bend locations were marked. If the arch matched the arch-form guide, anchor and/or gable bends were placed according to subsample designations; degree-bend guides were employed to standardize these bends. Final checks for flatness and parallelism were made before a specimen was accepted for testing. Five independent variables were incorporated in the research design: wire size, anchor-bend size, anchor-bend location, gable-bend size, and magnitude of Class II elastic force. The entire sample is detailed in Table II; the forces exerted by the elastics were established in grams, the units of the intrusive-force measurements. The appliance sample included fifteen arch-wire configurations and, with each wire, nine levels of Class II elastic force, for a total of 135 appliance configurations. Eight replications were performed, resulting in 1,080 separate intrusive-force measurements. Prior to testing, the orders of elastic-force magnitudes and arch-wire configurations were randomized. Following evaluation of the 120 wires at one elastic-force level, each arch wire was checked against the aforementioned guides to ensure that no inelastic behavior had occurred. (Any specimen found plastically deformed would have been rejected for subsequent testing, but none had to be so discarded.) After this check, testing was resumed at a new elastic-force level. Intrusiveforce values were recorded for all specimens accepted for testing. 14

Theoretical considerations The activation of the appliance under study is, in essence, the elastic bending of a cantilevered arch by the action of three loads: one from each of the elastics and the third from the anterior brackets. With the midsagittal-plane symmetry and the constant cross section throughout the arch, ignoring the localized inelastic effects of the bent-in circles and the second-order bends, and simulating the arch form with a circular or elliptical anterior section with attached, straight-line, posterior portions, a formula may be readily derived for small transverse bending deflections of the midpoint of the arch.26 The form of that expression is deflection = k(loading)s3(E-1) d-4

where k is a dimensionless constant, s is functionally related solely to the geometry of the arch form, E is Young's modulus of elasticity in bending for the arch material, and d is the diameter of the circular cross section of the arch.

While the objective of this research was to obtain empirical intrusive-force magnitudes, rather than to compare theoretical and experimental values, the results of the bench testing will provide some measures of the validity of the above equation. For example, for a given arch, the formula suggests a linear relationship between the Class II elastic forces and the intrusive force. The equation also implies that, if two appliances are identical in all characteristics except arch-wire size, the ratio of intrusive forces generated should be equal to the ratio of wire diameters raised to the fourth power. These two considerations and a third pertaining to the magnitudes of the activating deflections (and use of the small-deformation theory) are examined following the presentation of experimental results. Results A substantial number of Begg practitioners apparently employ the 0.016-inch wire in their Stage I mechanics, and statistical analyses of the experimental data from this sample resulted in Tables III and IV. Within the multiple-regression table, the ranges of standard regression coefficients suggest that the intrusive force is most strongly influenced by anchor-bend size and Class II elastic force; gable-bend size and anchor-bend location affected intrusive force mildly and only minimally, respectively. The coefficient rankings verify expectations in that (1) the higher the Class II elastic force, the less the potential for intrusion for a given set of anchor and gable bends and (2) increasing the size of either or both bends and moving the anchor bend distally will produce increased intrusive force. The analysis-of-variance results verify the influence and ranking of the individual independent variables and indicate that any and all stepwise variations in any independent-parameter value produced highly significant changes, statistically, in intrusive-force magnitude. Mean values of intrusive force for the 0.016-inch-wire sample have been tabulated (Table V) and plotted (Fig. 3). In order to examine the effect of arch-wire diameter on intrusive force in otherwise identical appliance designs, an analysis of variance was undertaken, including all suitably comparable data from the two wire samples (Table VI). In agreement with the theoretical development, wire diameter was found to be substantially more influential than the other independent parameters considered. The intrusive-force means for the 0.020-inch-wire sample have been tabulated (Table VII) and displayed graphically (Fig. 4). Discussion Interpretation of statistical results. The high coefficients of determination (R2, having an upper bound or limit of 1.0), as generated in the regression and variance analyses, attest to the inclusion in this study of the principal influencing independent variables, the adequacy of the number of replications, and at least nearly linear relationships between anchor-bend size and elastic-force magnitude, individually, and the dependent variable. The standard regression coefficients of Table III suggest that the specific placement in this arch size and form of a gable bend immediately distal to 15

the canine has slightly more than one half of the quantitative effect of an anchor bend of the same size. Strictly with regard to influence on intrusive-force magnitude, a change of 15 degrees in the anchor-bend size seems to correspond closely to a modification of 2 ounces in the Class II elastic force. The correlation ratios of Table IV indicate that the magnitudes of anchor bend and Class II elastic force have approximately equal impact on, and collectively control about three quarters of, the variance in intrusive force. Several first-order interactions, resulting from the analysis of variance of the 0.016-inch-wire sample data and detailed elsewhere,28 were significant and led to the following interpretations of interest: (1) The effect of gable bend upon intrusive forces appears to be independent of elastic-force size; addition of the 30-degree gable bend resulted in consistent increases in intrusive force with anchor-bend size and position held constant. (2) The greater the size of Class II elastic force, the less the influence of anchor-bend position on intrusive-force magnitude. (3) Anchor-bend position had a substantial impact on intrusive force only with the largest anchor bends of 60 degrees. Within the set of intrusive-force means for all of the 0.016-inch arch-wire configurations, no standard deviation exceeded 8 Gm. The three missing values are either zero or small extrusive forces which were not quantified (and were taken as zero in the regression analysis). The anchor-bend and elastic sizes, which are apparently most often employed by Begg practitioners using 0.016-inch wire, are 45 degrees and 2.0 to 2.5 ounces, respectively, yielding an intrusive force of approximately 40 Gm. Compared to the levels suggested independently by Burstone and Ricketts, the force is light, even if distributed only over the four maxillary incisors. The research results also support the suggestions by Sims of a sizable anchor bend plus inclusion of the gable bend; with 2 ounces of Class II elastic force and the largest bends employed in this study, the intrusive force barely reaches the magnitude suggested by Ricketts as appropriate for the incisor segment. Fig. 4 was generated, in essence, from Table V. Initially, the means for the two anchor-bend positions were averaged. After the individual data points were plotted to generate the six curves, recalling the theoretical analysis and the high coefficients of determination, the six straight lines were drawn, all with the same slope, without deviating from any data point by more than 4 Gm. (one half of the maximum standard deviation within Table V). The straight-line plots suggest close agreement between theory and experiment in the apparent linear relationship between elastic forces greater than 1 ounce and the intrusive force. (The plots were not extended to the zero-elastic-force values because of mixed nonlinearities associated with the maximum anterior activations.) All slopes being the same is indicative of the unchanging arch stiffness in the 0.016-inch-wire sample. Notable in Table V, but more vividly displayed in Fig. 3, are the similarities in intrusive-force magnitudes generated with anchor/gable bends of 45/0 and 30/30 degrees and with bends of 60/0 and 45/30 degrees, given any specific level of Class II elastic force. This phenomenon is also explained with the aid of the theory. The positions and the individual magnitudes of the localized, permanent bends apparently have a very small effect on the over-all behavior of the arch; the intrusive force is essentially determined only by the Class II elastic forces and the passive position of the anterior section of the arch after placement of elastics but prior to bracket engagement. The experimental comparison of appliances, with regard to the influence of arch-wire size on intrusive force, was somewhat limited. Anchor-bend size and position were held constant in the sample, but the variations in gable-bend size and elastic-force magnitude permitted generation of intrusive forces from eighteen passive anterior arch-segment configurations. The main-effects results displayed in Table VI indicate that wire size controls about 60 percent of the variance. Recall that the theory proposes that, while the intrusive force is proportional to the size of anterior archsegment activation, the force-deflection ratio in that activation depends upon the fourth power of the wire diameter. According to Table VI, increasing the wire diameter by 25 percent tripled the adjusted intrusive-force mean. For given values of the independent variables common to both tables, exclusive of the extreme levels of Class II elastic force, the intrusive-force magnitudes of Table VII are observed to be generally 200 to 250 percent greater than comparable magnitudes in Table V. The theory specifically predicts that the increase in diameter should raise the intrusive force (0.020/0.016)4 = 2.44 times, or 244 percent. The plots of Fig. 4 were generated from the tables of means for the 0.020inch-wire sample (Table VII) in the manner that was used in the preparation of Fig. 3. Again, the parallel straight lines may 16

be drawn, but compared to the 0.016-inch-wire results, the increased diameter reflects a consistent pattern of nonlinearity as the Class II elastic forces approach zero. Clearly, the lighter the elastic force, the greater the anteriorsection deflection necessary to engage the brackets. Also, it should be noted that the theory which predicts linear behavior is valid only for ''small'' deflections. Clinical implications. Generated from this bench study were values of intrusive force for an average arch size and multiple maxillary arch-wire configurations. Begg practitioners or other clinicians desiring to use the appliance can pick values from the tables of means or use Fig. 3 or 4, if the over-all arch dimensions conform reasonably with those of Fig. 1. Also, the levels of impact of the various independent variables on intrusive force are generally reflected in the analysis-ofvariance results. The most commonly employed Begg Stage I appliances, as described earlier, produce intrusive-force levels against the anterior segment substantially below those advocated by Burstone23 and by Ricketts and colleagues.24 This comparison might initially suggest that the commonly used Begg Stage I appliance is not stiff enough or the amount of activation is not sufficient to produce anterior intrusion. However, there are three noteworthy points, all of which apparently contribute to the intrusion potential of the appliance: First, the Begg appliance makes single-point contact with each tooth; hence, torque is absent and the anterior teeth can individually seek the path of least resistance in the intrusive displacement. Burstone23 noted that, if torque does not accompany the intrusive force, a light force can be clinically effective. McDowell29 earlier commented about the relative ease of intrusion when the tooth has lateral freedom and can move free of cortical-plate resistance. Second, since the relative anterior positions of the central and lateral incisors and canines are all different as measured in a buccal view from the terminal molars and the vertical distances from the passive arch wire to the central, lateral, and canine brackets are likewise different, and also because of the flexibility and resilience of the arch wire, the appliance, when activated, will not distribute the total intrusive force uniformly among the six teeth. The appliance, then, encourages differential progressive intrusion, and, as intrusion of one pair begins, localized, partial deactivation will result in the shifting of a portion of the loading on that pair to the other anterior teeth. Clinical evidence of this differential intrusion has been reported by Begg and Kesling6 and by Sims.21 Third, with the Class II elastics providing anteroposterior as well as vertical components of force, the potential for maxillary anterior retraction in the Begg Stage I appliance also exists. While Tables V and VII provide initial values of intrusive force, if anterior retraction occurs, the lever arms from the molars are shortened, resulting in an increased stiffness in those arms and accompanying potential for increased intrusive force. If intrusion and retraction occur simultaneously, the intrusive force may decrease at a lesser rate from its initial value than if intrusion alone took place. If retraction begins before intrusion, the intrusive forces may increase from their initial magnitudes, as has been suggested by Sims.7,21 With recognition of the retraction potential of the appliance, the importance of the position of the anchor bend becomes more clear. For maximum flexibility and an associated continuous intrusive action, irrespective of retraction, the anchor bend might be placed immediately adjacent to the buccal tube. However, with retraction apparently to occur during deactivation of the appliance, some initial mesiodistal clearance between bend and buccal tube is necessary to keep the bend from entering the tube and prematurely dissipating the intrusive force. Table V indicates the the contribution to intrusive-force variance of the step between 1 and 5 mm. of bend-tube clearance is generally less than ½ ounce and, apparently, nonsignificant from a clinical standpoint. The activation of an orthodontic appliance generally produces a force system against some anchorage in addition to the wanted action. Theoretically, with the Begg Stage I appliance under study, the response to the Class II elastics and anterior-segment engagement is a force-and-couple system exerted by the arch and transmitted through the buccal tubes to the terminal molars. Shown in Fig. 5 is a complete force diagram for one half of the symmetric arch wire in 17

buccal view (with second-order bends not detailed). Also shown are the active and responsive crown force systems against the anterior teeth (half segment) and the terminal molar in that view. A moment balance about the posterior end of the half arch gives Cm = Va(La + Lm ) + (FII sin 22º)Lm

and the total tipping moment about a buccolingual axis through the center of resistance of the molar is

Cm + Hm(d)

Substituting into these equations typical anteroposterior arch dimensions, a Class II elastic-force (FII) magnitude of 2 ounces (57 Gm.) and an intrusive force (Va) of 20 Gm. against one half of the anterior segment yields a Cm value of nearly 1,200 Gm. mm. and a tipping moment likely in excess of 1,400 Gm. mm. Burstone23 has suggested that such a moment magnitude is sufficient to tip a maxillary first molar. Although this computation does not include the effect of posterior occlusion which, if present, adds to the potential stability of the molar, the large moment arms result in a sizable couple Cm, even with a light intrusive force. Clearly, the tendency for molar tipping is a side effect of appliance action which must be monitored. Although in specific cases this tipping might be allowable toward the correction of a Class II malocclusion, noteworthy is the effect accompanying molar displacement of a reduction in magnitude of the active force system with a corresponding decrease in the intrusive potential of the appliance.

Summary and conclusions The purpose of this research was to study quantitatively the intrusive force delivered to the anterior segment by a number of variations of the maxillary appliance employed in Begg Stage I therapy. Maintaining over-all dimensions to fit an average maxillary dentition, varied in the experimentation were sizes of anchor bend and gable bend, Class II elasticforce level, to a limited extent arch-wire diameter, and anchor-bend position. One hundred thirty-five appliance configurations were evaluated. A substantial range of intrusive-force magnitudes was obtained. The force data were reduced and examined through suitable statistical procedures. Significant results of the investigation may be summarized as follows: 1. Four commonly used appliance configurations generated initial mean values of intrusive force, distributed (although nonuniformly) over the four- or six-tooth segment, of approximately 40 grams. 2. Of the four independent parameters varied in appliances employing 0.016-inch wire, anchor-bend size and Class II elastic-force magnitude were most influential in increasing and decreasing, respectively, anterior intrusive force. 3. Within the 0.016-inch-wire sample, addition or deletion of a gable bend quantitatively affected intrusive force almost independently of the magnitude of Class II elastic force. 4. Variation in the location of the anchor bend, up to 5 mm. mesial to the buccal tube, had a very small influence on the intrusive-force size. 5. Several combinations of independent-variable values, in identifiable patterns, contributed to the generation of similar intrusive-force magnitudes. 18

6. Increasing the wire diameter 25 percent, from 0.016 to 0.020 inch, resulted in dramatically raised intrusive-force values generated by the appliances. The higher force magnitudes were in general agreement with the arch-bending theory which predicts an increase of 244 percent. The results of this study apparently warrant the following conclusions: 1. The commonly used maxillary appliances of Begg Stage I mechanotherapy produce initially light but continuous force against the anterior segment. With no torque potential in the appliance, the teeth may seek the intrusive path of least resistance. 2. Increasing (decreasing) the sizes of the anchor and/or gable bends may be equivalent to decreasing (increasing) the Class II elastic force with regard to the effect on intrusive potential. Not to be overlooked, however, is the fact that alterations in the elastic force also affect the horizontal action of the appliance, whereas the bends do not. 3. In fabricating the appliances studied, with their common over-all design, the approximate magnitude of intrusive force desired should be approached from the low side through an appropriate combination of anchor-bend size and Class II elastic-force magnitude, with the operator being mindful in the placement of the latter of its horizontal component. Subsequently, as necessary, a gable bend should be placed and adjusted in size, verifying the amount of intrusive force to be delivered with a force gauge. 4. Anchor-bend position is much more important in providing clearance for potential retraction accompanying intrusion than it is in influencing intrusive-force magnitude. 5. Because of long moment arms, even a light force against the anterior segment will result in sizable tipping moments against the molars. Accordingly, molar positions must be monitored while the appliance is active, and if unwanted displacements occur, anchorage reinforcement may be necessary. 6. A controlled clinical investigation, correlating the measured intrusive-force magnitudes, the amount of anteriorsegment displacement, and any anchorage movement during Stage I of pure Begg treatment mechanics, is needed to clarify whether or not the appliance design examined in the present bench research actually produces the displacement desired. Such an investigation, with the results reported in this article, could lead to advocacy of appropriate intrusiveforce magnitudes and modifications in the appliance design.

Ref.

Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1981 Jun (610 - 624): Maxillary anterior intrusive forces generated by Begg Stage I appliances - Thornton and Nikolai. -------------------------------1. Swain, B. F., and Ackerman, J. L.: An evaluation of the Begg technique, AM. J. ORTHOD. 55: 668-687, 1969. 2. Cadman, G. R.: Nonextraction treatment of Class II, Division 1 malocclusion with the Begg technique, AM. J. ORTHOD. 68: 481-498, 1975. 3. Sims, M. R.: Anchorage variation with the light wire technique, AM. J. ORTHOD. 59: 456-469, 1971.

19

4. Daruwala, N. R., and Joshi, M. R.: Tooth movement during bite opening in stage I of Begg technique— A cephalometric study, J. Indian Orthod. Soc. 4: 58-65, 1973. 5. Levin, R.: Begg orthodontic therapy in retrospect, Dissertation, State University of Groningen, The Netherlands, 1975. 6. Begg, P. R., and Kesling, P. C.: Begg orthodontic theory and technique, Philadelphia, 1977, W. B. Saunders Company. 7. Sims, M. R.: Personal communication, Department of Orthodontics, University of Adelaide, South Australia, 1978. 8. Rocke, R. A.: Management of the overbite within the vertical dimension, Begg J. Orthod. Theory Treat. 3: 9-13, 1964. 9. James, A. T.: Changes in the vertical relationships of teeth during and following use of the Begg light wire technique, AM. J. ORTHOD. 54: 152, 1968. 10. Crytzer, M. R.: Tooth movement with the Begg technique, Begg J. Orthod. Theory Treat. 8: 81-96, 1969. 11. Williams, R. T.: Cephalometric appraisal of the light wire technique. In Begg, P. R., and Kesling, P. C. (editors): Begg orthodontic theory and treatment, ed. 3, Philadelphia, 1977, W. B. Saunders Company. 12. Thompson, W. J.: Occlusal plane and overbite, Angle Orthod. 49: 47-55, 1979. 13. Hurd, J. J., and Nikolai, R. J.: Maxillary control in Class II, Division 1 Begg treatment, AM. J. ORTHOD. 72: 641-652, 1977. 14. Ten Hoeve, A. T., Mulie, R. M., and Brandt, S.: Technique modifications to achieve intrusion of the maxilliary anterior segment, J. Clin. Orthod. 11: 174-198, 1977. 15. Rocke, R. A.: The effect of Begg therapy on the palatal plane and vertical position of the maxillary incisors, Master's thesis, Saint Louis University, St. Louis, 1973. 16. Kesling, P. C.: Analysis of individual tooth movements during Begg light wire treatment, Thesis submitted to the American Board of Orthodontics, 1968. 17. Payne, C. J.: Changes in the apical base relations and the vertical position of the maxillary central incisor incident to treatment with the Begg light wire differential force technique, Master's thesis, University of Tennessee, Memphis, 1966. 18. Sims, M. R.: The Begg philosophy and treatment technique, Begg J. Orthod. Theory Treat. 6: 23-36, 1967. 19. Begg, P. R.: Light arch wire technique, AM. J. ORTHOD. 47: 30-48, 1961. 20. Swain, B. F.: The Begg technique. In Graber, T. M., and Swain, B. F. (editors): Current orthodontic concepts and techniques, ed. 2. Philadelphia, 1975, W. B. Saunders Company, vol. 2. 21. Sims, M. R.: Conceptual orthodontics, AM. J. ORTHOD. 71: 431-439, 1977. 22. Sims, M. R.: Loop systems: A contemporary reassessment, AM. J. ORTHOD. 61: 270-278, 1972. 23. Burstone, C. R.: Deep overbite correction by intrusion, AM. J. ORTHOD. 72: 1-22, 1977. 24. Ricketts, R. M., Bench, R. W., Gugino, C. F., Hilgers, J. J., and Schulhof, R. J.: Bioprogressive therapy, Denver, 1979, Rocky Mountain Orthodontics. 25. Newman, G. V.: A biomechanical analysis of the Begg light wire technique, AM. J. ORTHOD. 49: 721-740, 1963. 26. Timoshenko, S.: Strength of materials, ed. 3, Princeton, N. J., 1955, D. Van Nostrand Company. 20

27. Kirk, R. E.: Experimental design: Procedures for the behavioral sciences, Belmont, Calif., 1968, Brooks/Cole Publishing Company. 28. Thornton, C. B.: Fundamental mechanisms of maxillary incisor intrusion in Stage I of Begg mechanotherapy, Master's thesis, Saint Louis University, 1979. 29. McDowell, C. S.; The hidden force, Angle Orthod. 37: 109-131, 1967.

Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1981 Sep (300 - 315): Controlled movement of maxillary incisors in the Begg technique - Liu and Herschleb --------------------------------

Controlled movement of maxillary incisors in the Begg technique Shin-Yang Liu, B.D.S., M.P.H., and C. Wilson Herschleb, D.M.D. Boston, Mass. The force system and anchorage used in the Begg technique have an inherent shortcoming in their ability to achieve intrusion of maxillary incisors, which is often indicated in treatment. Furthermore, the round-tripping of the maxillary incisors during their retraction has proven mechanically and biologically disadvantageous. Using the Begg principles, a modified force system was designed, in which Class I elastic traction and strong anchor bends are used, along with a strengthened anchorage unit (transpalatal block anchorage), to achieve controlled and effcient movement of the maxillary incisors. 21

The Begg technique has been used with considerable success since its introduction in 1956.1 Many orthodontists adopted this technique because it held promise for rapid correction of deep overbite and overjet with a differential force system that obviated the use of headgear for maintaining anchorage. The Begg technique supposedly also reduced treatment time. In its clinical application, however, some difficulties were encountered, and a number of modifications and refinements were made in subsequent years to bring this technique to fruition.2 Critical examination of treatment progress and treatment results has shown that, like all other methods, the Begg technique is not a panacea and that great vigilance must be maintained to prevent or intercept undesirable tooth movements. One important disadvantage of the Begg technique is the difficulty of intruding maxillary incisors during their retraction. In fact, maxillary incisors are often extruded, notwithstanding the attempt made in the classic Begg technique to inhibit extrusion of incisors by increasing the anchor bends in the maxillary arch wire. The vertical component of Class II elastic traction counteracts the intrusive force from the anchor bends, and the maxillary incisors extrude in some instances. Moreover, distal tipping and extrusion of maxillary molars have been observed in response to the heavy anchor bends in the arch wire, which further dissipates the desired intrusive force on the maxillary incisors. Ten Hoeve and associates3 as well as Hocevar,4 advocated the use of vertical elastics between maxillary and mandibular molars to prevent distal tipping of the maxillary molars. Unfortunately, vertical elastics tend to extrude both maxillary and mandibular molars. As an alternative, a high-pull headgear force system has been used to counteract the distal tipping of the molars from heavy anchor bends, but the wearing of headgear during a critical phase of treatment entails a risk because success depends on full cooperation of the patient. Extrusion of mandibular molars for bite opening can be hazardous to facial harmony and optimal tooth alignment in the patient with a Class II hyperdivergent facial pattern and long lower face height. In addition to the aforementioned shortcomings, correction of overjet in the Begg technique is achieved through roundtripping of maxillary incisors, which is mechanically and biologically disadvantageous.5,6 To circumvent these adverse effects, a modification of the Begg technique was designed to provide controlled movement of the maxillary incisors through an individualized force system and consolidation of anchorage. Instead of using Class II elastic traction, Class I elastic traction is judiciously combined with strong anchor bends. Deliberate consideration of anchorage conservation is essential, because the resultant of the retractive and intrusive forces that lies distant to the maxillary molars will induce adverse movements or anchorage loss of the maxillary molars (Fig. 1). In the modified force system, anchorage of the posterior teeth is strengthened by consolidating the maxillary left and right posterior teeth into a solid unit reinforced with a transpalatal bar. This bar is soldered to the maxillary first molars, because frictional fit in a lingual lock may induce habitual play by the tongue. Furthermore, buccal and lingual wires are soldered to the bands for maximal immobilization. No effort is made to align the posterior teeth prior to construction of the transpalatal bar in the assumption that a relatively unmoved tooth provides the best anchorage. This method is referred to as transpalatal block anchorage, or TPBA. Clinical experience has shown that this anchorage system also requires an intact occlusal table; that is, each maxillary premolar and molar contained in the anchorage unit must occlude with opposing teeth in the mandibular dentition. This important consideration became obvious when the TPBA was used in a patient for whom maxillary first premolars and mandibular second premolars had been extracted. The maxillary TPBA unit began to rotate or ''dump'' into the extraction space of the mandibular premolar. When the occlusal table opposing the anchor unit is maintained, the TPBA functions properly. Design of force system

22

The clinician is faced with determining the proper ratio between intrusive and retractive forces for the correction of overjet and overbite. On the pretreatment cephalogram, the anticipated posttreatment position of the maxillary incisor is drawn. Moreover, the long axes through the pre- and posttreatment outlines of the maxillary incisors (L1 and L2) are drawn until they intersect. The angle (q) between the two long axes (L1 and L2) defines the amount of rotation required to correct the overjet of the maxillary incisors (Fig. 2). The center of resistance of the maxillary central incisors in the pre- and posttreatment positions is arbitrarily set at 40 percent of the root length (that is, the distance from the alveolar bone crest to the root apex). A coordinate system is drawn with its origin at the center of resistance of the pretreatment maxillary incisor (R1) and the abscissa parallel to a reference line, such as the palatal plane (Fig. 2). The projected distances from the center of resistance of the posttreatment maxillary incisor (R2) to the Y and X axes indicate the amount of required retraction and intrusion, respectively. To calculate the force system for controlled incisor movement (Fig. 3), the following equation is used:

where

K = the ratio between moments Fy · D1 and Fx × D2 Fy = intrusive force Fx = retractive force D1 = distance from R1 to the Fy D2 = distance from R1 to the Fx Fy · D1 = counterclockwise moment induced by Fy Fx × D2 = clockwise moment induced by Fx

Five factors are considered in the equation: Fx, Fy, D1, D2, and K. Of these, D1 and D2 are known. Value K is determined by angle q and the location of the center of rotation of the maxillary incisor. If the treatment objective is to secure pure translation of the incisors, angle q is zero and value K equals 1. A small angle e infers the need for slight rotational movement of the incisors, and consequently value K will be close to 1. With increasing amounts of incisor rotation, values for K will either decrease or increase, depending on the direction of required rotation (Fig. 4). For instance, the value of K will be 0.8 when a clockwise rotation of the maxillary incisors, ranging from 11 to 20 degrees, is required, and value K will be 1.1 for counterclockwise rotation no larger than 10 degrees. Fy, the intrusive force, is predetermined by the clinician at either 80 or 100 Gm., depending on the amount of intrusion required. Inasmuch as the retractive force (Fx) is the only unknown factor in the force system, it can be readily calculated by substituting all other values in the formula. The procedure may be illustrated by four examples, in which varying amounts of incisor retraction, intrusion, and rotation are required. Example 1. For the correction of overjet and overbite, 5 mm. of retraction, 3 mm. of intrusion, and 10 degrees of rotation of the incisors are required (Fig. 5, A). Since the amount of rotation is small, the value of K is 0.9, according to the schematic drawing shown in Fig. 4. An intrusive force of 100 Gm. will be used to achieve the rather extensive intrusion. D1 and D2 are measured from Fig. 5, B. The amount of Class I elastic traction can now be calculated, substituting the values for K, Fy, D1, and D2 in the formula: 23

Thus, 100 Gm. of Class I elastic traction (50 Gm. applied bilaterally) and 100 Gm. of intrusive force provide the force system needed to achieve the specified movement of the maxillary incisors. Example 2. In this instance, 4.5 mm. of retraction, 1.5 mm. of intrusion, and 18 degrees of rotation are required for optimal positioning of the incisors (Fig. 6, A). Value K will be 0.8 for a rotation of 18 degrees, as shown in Fig. 4. A force of 80 Gm. is selected for the slight intrusion. Both D1 and D2 are 11 mm. and Fx is computed to be 100 Gm:

Therefore, an 80 Gm. intrusive force and 50 Gm. Class I elastic traction on each side of the maxillary arch are needed to achieve the desired movement of the maxillary incisors. Example 3. In this example, 7 mm. of sagittal translation of the maxillary incisors is required, which implies that the value of K is 1, and a moment of the same magnitude and opposite in direction of that induced by Class I elastic traction is needed to secure sagittal translation of the incisors. Since intrusion of the maxillary incisors is not indicated (Fig. 7, A), the counterclockwise moment should be induced by a torquing auxiliary. Therefore, the formula is slightly modified, replacing "Fy × D1" by "M," which is a pure counterclockwise moment created by the torquing auxiliary:

The computation indicates that M1 and FX are interrelated in a ratio of 10 to 1, regardless of their units (Fig. 7, B). For instance, a 1,000 Gm. mm. counterclockwise moment has to be provided with a torquing auxiliary to balance the clockwise moment created by 100 Gm. of Class I elastic traction. Example 4. Translation of incisors along their long axis is conventionally called pure intrusion (Fig. 8, A). Actually, this socalled pure intrusion requires a horizontal, as well as a vertical, force component, because the center of resistance of the tooth is moved upward and backward (Fig. 8, B). For this kind of tooth movement, K = 1, because the angle q is zero (no change in axial inclination). Assuming an intrusive force (Fy) of 100 Gm., the retraction force (Fx) can be calculated for the example shown in Fig. 8, B, as follows:

This example illustrates the confusion and misunderstanding created by current terninology of tooth movement. We suggest a new approach, in which the change of the center of resistance of a tooth is defined by its horizontal and vertical components within a coordinate system. Moreover, the required change in the axial inclination of the tooth is expressed by the angle formed by the long axes of the tooth (L1 and L2). In the context of this system, pure intrusion occurs only by vertical displacement of the center of resistance, maintaining parallelism of the axial inclincation inclination of the tooth, as shown in Fig. 9, A. To achieve genuine intrusion, a clockwise movement is required to counterbalance the opposite moment induced by the intrusive force. For the example shown in Fig. 9, A, the clockwise moment is 500 Gm. mm. (Fig. 9, B). Clinical application 24

The treatment of a Class II Division 1 type of malocclusion with extraction of four first premolars will be described to illustrate the clinical application of this modification of the Begg technique. Construction of anchorage unit. Bands are fitted on the maxillary first molars and second premolars with sufficient tolerance to permit the seating and cementing of the TPBA unit as a soldered block. An impression is taken and bands are inserted in their proper places and secured with a metal wire or sticky wax. On the dental cast, round 0.040 inch wires are soldered as far gingivally as possible to the buccal and lingual surfaces of the molar and premolar bands. Tubes (0.036 inch) are soldered on the buccal surfaces of the first molars occlusal to the wire bars. Finally, a transpalatal bar of 0.040 inch round wire is carefully shaped along the palatal contour and soldered against the lingual bar connecting the premolars and molars on each side. The unit is cleaned and cemented on the teeth. (Note that second molars may also be included in the anchorage unit.) First phase of treatment. Maxillary and mandibular incisors and canines are aligned with 0.016 inch looped arch wires with anchor bends, as in the conventional Begg technique, and light (1 ounce) Class I elastics are prescribed to prevent flaring of incisors . The use of a looped arch wire is postponed, however, if a large (approximately 2 mm.) vertical discrepancy between the incisal edges of the anterior teeth is encountered (for example, high canines or overerupted central incisors). In such instances, the overerupted incisors are pinned to the arch wire, while the remaining anterior teeth are lightly tied. As the overerupted teeth are brought to the level of their adjacent teeth, the latter are also pinned to the arch wire until all vertical corrections have been achieved. Second phase of treatment. The force system to secure controlled movement of the maxillary incisors (intrusion, uprighting, translation, and torque) is delivered by anchor bends in an 0.016 or 0.018 inch arch wire, combined with Class I elastic traction and a torquing auxiliary arch whenever required. The TPBA and an intact occlusal table provide the necessary anchorage for this force system. Clinical experience has shown that optimal intrusive forces, obtained from a 70-degree anchor bend in the maxillary arch wire, range between approximately 80 and 100 Gm. Forces beyond 100 Gm. readily cause loss of anchorage control, while forces below 80 Gm. do not produce efficient intrusive movement of incisors. As a general guideline, an 80 Gm. force should be used for slight intrusion of incisors and a 100 Gm. force should be used in instances where extensive intrusion is required. In each instance, the actual intrusive force exerted by the arch wire must be determined with a force gauge pulling the wire downward along the midline between the incisors to the midpoint of the vertical slots of the brackets. The arch wire should be free of contact with the brackets on the teeth to permit accurate reading of the intrusive force. This requirement demands slight labial displacement of the arch wire to clear all interferences. However, the intrusive force of an 0.016 inch arch wire is decreased 6 Gm. for each millimeter of labial displacement and 12 Gm. for an 0.018 inch arch wire, as determined experimentally. The reading of the force gauge must be corrected, therefore, by adding 6 Gm. for each millimeter of labial displacement of the 0.016 inch arch wire necessitated by clearing bracket interference. The intrusive force determined in situ will in all probability range between 80 and 100 Gm., but the actual force measured should be used in the equation to calculate the horizontal force. Class I elastic traction closely approximating the required horizontal force should be worn until the predetermined position of the maxillary incisors has been reached. The force system should be re-evaluated during treatment, on the basis of positional changes of the incisors. For each adjustment of the force system, a cephalogram must be obtained and the analysis outlined above must be repeated. Class II elastic traction is not used during treatment to capitalize fully on the force from the anchor bends for achieving genuine intrusion of the maxillary incisors and to avoid extrusion of the mandibular molars. Positioning of incisors in the 25

mandibular arch is obtained by the proper combination of Class I elastic traction, anchor bends, and braking auxiliaries according to the Begg principles of tooth movement with a differential force system.2 Third phase of treatment. After correction of the overjet and closure of interdental spaces, the TPBA may be left in the mouth until the completion of treatment. When spaces remain distal to the maxillary canines, the TPBA is removed to facilitate protraction of the posterior segments. Removal of the TPBA requires fitting of new bands on the second premolars and molars. An ideal 0.018 inch arch wire should be placed with 15- to 20-degree anchor bends to maintain the vertical position of the incisors. Braking auxiliaries, such as a passive torquing auxiliary or passive canine uprighting springs, can be placed to retain anterior segments. In this modification, the third stage of the Begg technique consists of the usual uprighting procedures, although the maxillary second premolars frequently do not require uprighting because they have been maintained in their original positions. Moreover, the controlled movement of the maxillary incisors obtained with this modification of the Begg technique obviates the routine requirement for incisor torque in the conventional application of the Begg technique. Case reports Case 1 The first clinical illustration of the potential of the Begg technique modification presented above concerns a patient with a Class II, Division 1 type of malocclusion, distoclusion of molars, 7.5 mm. of overjet, a moderate (40 percent) overbite, and moderate crowding of the maxillary and mandibular incisors (Fig. 10). Clinical examination and a cephalogram (solid line in Fig. 11) revealed bimaxillary protrusion and a convex profile outline. Conventional Begg treatment procedures had been initiated after extraction of the four first premolars. A review of treatment progress after 7 months revealed that neutroclusion on molars was obtained by mesial movement of the mandibular molars, but two thirds of the extraction spaces were still present, while the maxillary incisors were overuprighted (Fig. 12, A), and slight clockwise rotation of the mandible had occurred during the increase in lower face height (Fig. 11). It was obvious that continued tipping of the incisors to close extraction spaces was needed, but considerable difficulty was expected in the achievement of sufficient root torque of the incisors during the third space to align the teeth properly. Moreover, rotation of the mandible could be expected to continue with detrimental effects on the soft- and hard-tissue facial pattern. The modified technique was therefore used to complete the treatment. After transpalatal block anchorage was constructed and an individual force system analysis was made, treatment continued with Class I, rather than Class II, elastic traction in all four quadrants of the dental arches. A torquing auxiliary creating a counterclockwise moment was inserted to counterbalance the clockwise moment induced by the Class I elastic traction. Slight anchor bends were incorporated in the maxillary arch wire to prevent extrusion of the incisors. During the first 4 months of treatment, maxillary incisors were translated over a 3 mm. distance, maintaining complete parallelism of the root outlines. The maxillary first molars showed minimal extrusion (Fig. 13, B). Increased activation of the torquing auxiliary, along with continuous wearing of Class I elastics, during a 5-month period provided satisfactory results in establishing the proper inclination of the maxillary incisors (marked root torque with only slight labial crown movement, Fig. 12, C). The analysis of treatment results reveals normal overbite, overjet, and interdigitation of the teeth. The maxillary incisors were efficiently moved to the predetermined position without jeopardizing anchorage of the posterior teeth in the maxillary arch (Fig. 13, and Fig. 12, A-D). Superposed tracings of cephalograms taken at the start of the modified Begg technique and the closure of extraction spaces reveal favorable forward growth of the mandible (Fig. 13, B).

26

The second and third cases involve correction of Class II, Division 1 malocclusions treated entirely according to the principles of the modified Begg technique. Case 2 In this case only minimal changes of the first molars occurred, which infers satisfactory anchorage preservation. Movement of the incisors conforming to the specific treatment objectives and determination of an optimal force system for this patient resulted in correction of the 6 mm. overjet with marked intrusion of the maxillary incisors (Fig. 14, A-D). Case 3 A skeletal Class II facial pattern with bimaxillary protrusion of the incisors and a Class II type of malocclusion were characteristic features of Patient 3. Marked changes were obtained in the incisor position during a 6-month treatment period, as shown in Fig. 15, A-C. Clockwise rotation (20 degrees), intrusion (3 mm.), and retraction (8 mm.) of maxillary incisors were accomplished in this relatively short period of time with the modified Begg technique outlined in the report. Conclusion This modification of the Begg technique holds promise for further clinical application. Yet, considerable care must be exercised to monitor the movement of anterior teeth and the stability of the anchorage unit throughout treatment. Recalculation of the force system may be necessary during treatment evaluation. Efficient movement of anterior teeth with proper anchorage control has been a critical issue in all orthodontic techniques. The method presented furnishes a rational basis for approaching this problem. The authors express their gratitude to Dr. Stella Efstratiadis, Instructor in Orthodontics, for the cephalometric analyses of treatment results presented.

Ref. Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1981 Sep (300 - 315): Controlled movement of maxillary incisors in the Begg technique - Liu and Herschleb. -------------------------------1. Begg, R. R.: Differential force in orthodontic treatment, AM. J. ORTHOD. 42: 481-510, 1956. 2. Cadman, G. R.: A vade mecum for the Begg technique: Technical principles and treatment procedures, AM. J. ORTHOD. 67: 477-512, 601-624, 1975. 3. Ten Hoeve, A., Mulie, R. M., and Brandt, S.: Technique modifications to achieve intrusion of the maxillary anterior segment, J. Clin. Orthod. 11: 174-197, 1977. 4. Hocevar, R. A.: Begg and beyond: The latest and best in orthodontic mechanism, N. Z. Orthod. Soc. Newsletter, November, 1979. 5. Ten Hoeve, A., and Mulie, R. M.: The effect of anteropostero incisor repositioning on the palatal cortex as studied with laminagraphy, J. Clin. Orthod. 10: 804-822, 1976. 6. DeAngelis, V.: Observations on calvarial growth in rachitic and healing rats, Am. J. Anat. 124: 379-388, 1969. 27

Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1981 Jun (591 - 609): Begg and straight wire Thompson --------------------------------

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Begg and straight wire: A combination approach to treatment William J. Thompson, D.D.S. Bradenton, Fla. Orthodontic appliances should be designed to satisfy goals for denture, patient, and doctor. An appliance that is able to achieve these goals more closely approaches the ideal treatment system. Analysis of appliances of the Begg and straight wire types indicates that each treatment system has significant advantages and that the advantages of one system frequently are the disadvantages of the other. A technique that uses both the tipping principles of Begg and the bodily movement principles of the straight wire type of appliance has been designed and clinically evaluated. The unique capability of the combined treatment approach is in the mechanical design of the new combination four-stage bracket. A description of the appliance and the technique, as well as a clinical case presentation, is included in this article. Begg appliances and appliances of the straight wire type have been known to produce fine orthodontic results. An analysis of these appliances, however, shows that each has unique characteristics which can be advantages or disadvantages in a total treatment program. The objective of this article is to describe the advantages and disadvantages of the classic Begg and straight wire appliances and to suggest a treatment approach that uses the advantages of each while minimizing the disadvantages. The comparisons of the straight wire appliance in the discussion will relate to the methods of using straight, continuous arches with sliding mechanics and full-size finishing wires where possible. The comparisons of the Begg appliance are based upon use of the traditional Begg system employing round wires, anchor bends, Class II elastics, and auxiliaries as necessary. A concise description of the essential procedures with a combination bracket (Begg and straight wire) is provided. Both static and functional occlusions are of importance to orthodontists. since the early discussions of occlusion by Brodie and Thompson,1 orthodontists have become increasingly aware of and concerned about functional occlusal harmony. In recent years, the literature has been filled with research and clinical material about occlusion and function in orthodontics, relating it to diagnosis, treatment planning, appliances, and retention.2-9 Much of the clinical material related occlusion to angulation, axial rotation, and torque of teeth in order to form maximum intercuspation. In search of an appliance technique capable of an individualized, comprehensive approach to each patient's treatment, the orthodontist must satisfy goals in three principal areas, namely, for the denture, the patient, and the doctor. The significance of these goals should be shared by both the patient and the orthodontist. Each appliance system, however, does not necessarily provide the optimum effectiveness in accomplishing all of these mutual goals.10-19 The orthodontist must carefully evaluate what his appliance can do and be willing to modify his technique to increase its effectiveness toward satisfying the maximum number of mutual goals. In order to increase the total effectiveness of a treatment program, it is suggested that the favorable mechanical capabilities of one or more appliance systems be combined into a synergistic type of mechanics. One such treatment approach might involve light, rapid tipping forces to correct gross changes in tooth position at one stage in treatment, while more rigid and precise appliances are used later in treatment to produce maximum tooth detailing and occlusal intercuspation. Such a combination of treatment capabilities enables the practitioner to achieve selectively or collectively, in an optimum way, the various goals for the denture, patient, and doctor. The Begg technique uses a pin-and-tube bracket which facilitates one-point contact. Using continuous, small-diameter round wires, elastics, and springs, the force system is designed to provide tipping movement. The edgewise bracket with continuous rectangular wires facilitates a bodily type of movement with torque control.12,19 Each of the systems has produced satisfactory orthodontic results over the years, and each has undergone a multitude of improvements. The 29

most current evolutionary change in the edgewise system is the addition of the straight wire type of appliance.10,13,2022 Each has its unique advantages and disadvantages and can be shown to provide certain favorable treatment responses. Use of both the tipping and bodily movements at specific times in treatment does produce a diversified treatment system that can be an unusually effective combination. The Begg system, developed by Dr. P. Raymond Begg,12,23,24 was originally defined as a differential-force, light-wire appliance. Differential force can be described as a dynamic interaction of physiologic and appliance forces that form an anchorage system and a moving system in treatment. A concept that includes dynamics of function and differential dental anchorage is based upon the philosophy that muscle forces, functional forces, inclined planes and occlusal forces, other physiologic forces, and even nonphysiologic forces, such as habits, are placed in action or reaction with Begg appliance forces produced from anchor bends, wire design, bracket contact, and elastic pressures. Properly designed, the differential system permits effective posterior anchorage stability with light, rapid tipping and intrusion of anterior teeth. The predictability of many tooth movements may be due to the direct influence of the forces of physiology that are an effective part of the true differential system. Several past clinical studies have documented the capability and predictability of the Begg system to produce consistent treatment changes.8,11,12,25-31 Clinicians familiar with the Begg system recognize their ability to open bites, retract incisors, torque incisors, and upright roots (Figs. 1A, 1B, and 1C). It is also significant that the maximum flexibility of the appliance and the greatest degree of tooth movement occur in the early stages of treatment. These stages— Stages I and II— are the periods of treatment in which differential force is critical, tooth movements are very rapid, and the physiology of freeway and functional occlusion are of paramount importance in establishing maximum posterior anchorage.32-35 Personal observations and discussions with other Begg clinicians have frequently confirmed the fact that the mechanics in Stage I and Stage II are the keys to success in Begg treatment, since they determine the effective bite opening, the optimum anteroposterior positioning of incisors, and stability of the molars. It must be realized at this point that these favorable characteristics of Begg treatment occur in the early periods of treatment, during unraveling, bite opening, and anterior retraction, when physiologic tipping of teeth is desired and most effective (Fig. 2). Little has been said about the Begg appliance in the finishing stages. Probably the most difficult part of Begg treatment is the finishing period, and this problem area has been addressed before.36 Control of buccolingual torque on posterior teeth is difficult in the Begg system and requires special auxiliaries to achieve good occlusal position. The ease of tipping on the single-point contact tends to permit undesirable tooth movements during the finishing periods. These movements can be produced by occlusal forces, functional interferences, damaged or bent arch wires, habits, and other minute, extraneous forces. The forces are capable of opening spaces, tipping teeth, and generally producing undesirable movements which frequently require additional appointments and adjustment procedures to obtain the optimum occlusal finish. Stage IV movements in Begg treatment are, theoretically, those added adjustments which are needed to obtain the optimum finish to the occlusion.36 It should be noted here that these precise finishing movements are late treatment procedures and are distinctly different from the rapid, gross changes achieved so effectively by Begg technique at the beginning of treatment (Fig. 3). Appliances of the straight wire type appear to have some distinct advantages over the Begg system at certain points of treatment.22,37,38 These are principally related to the precision type of bracket and arch wire design. The wider twin bracket with the shorter interbracket distance used in some systems increases the rigidity of the continuous straight wire. It tends to increase the forces applied interdentally, increases the friction, and places positive three-dimensional forces and couples on the teeth. The rigidity of the straight wire, although having the potential of a more precise appliance with closer tolerance or fitting, has certain mechanical disadvantages in early alignment and leveling procedures. The inflexibility and friction of the appliance are magnified in the initial arch wire sizes because of the significantly greater angular position of the slots produced by the malposition and tipped teeth in the original malocclusion. The continuous 30

leveling arch wires in the greatly angulated straight wire slot sequence set up extraneous forces among the teeth which tend to produce leveling by forward movement of anterior teeth.39 Unlike the single-point Begg bracket, the teeth cannot tip freely into extraction sites, and the typical intrusion and lingual tipping of incisors seen in the Begg treatment are not evident. In addition, anchorage support from an extraoral or intraoral appliance is frequently recommended to control the diversified forces generated in the irregular-slot brackets as alignment or retraction of teeth is performed. Bite opening in conventional straight wire mechanics is not as rapid as it is in the Begg system, where bite opening is effectively undertaken early in treatment by molar elevation and incisor intrusion which occur simultaneously with the en masse retraction of incisors. In spite of the apparent difficulties that can arise during the early periods of treatment with the straight wire appliance, it has been shown to produce fine precision and quality of occlusion in the finishing of treatment.13,22 The ability to place teeth closer to proper occlusal position with preangulated and pretorqued brackets with less arch wire manipulation is a definite treatment advantage. The heavier forces produced over shorter interbracket distances with precisely fitting rectangular wires in a rectangular slot establish excellent positive control in three dimensions, provide precise movements, and eliminate the undesirable tipping frequently seen during finishing procedures in a Begg system. In addition, the three-dimensional capability of the rectangular wire does provide a more accurate means of achieving total coordination of arch wires in both arches to provide optimum occlusal intercuspation. In this overview of Begg and continuous straight-wire appliances it appears that advantages and disadvantages of each system are due to the inherent characteristics in the design of the two systems. Each is constructed to perform one function best— Begg to produce gross movements rapidly with tipping, straight-wire to perform precise bodily movement over shorter distances in a force system of a more static nature. The Begg system is rapid in early treatment but becomes more cumbersome in the finishing stages. The straight wire system is prone to complications in early periods of treatment but is efficient in the final finishing adjustments (Fig 4). An appliance design that captures the advantages of both systems and reduces the disadvantages of both is the topic of discussion in the remaining part of this article. A new bracket concept and a treatment approach will be described. The new appliance enables the orthodontist to combine both the tipping and bodily movement principles of mechanics. The system permits the use of pure Begg mechanics in that part of treatment and in those cases in which it is most effective. It also permits the use of a straight wire appliance in the same cases or in any cases in which a rigid, preangularpretorqued finishing procedure is desired. The dual capability of the appliance system is due to a combination bracket design in which the lower third of the bracket is a Type 256 Begg bracket and the upper two-thirds of the bracket is a 0.018 by 0.025 inch straight wire slot with in-and-out positioning, preangulated and pretorqued (Figs. 5, 6, and 7). The Begg slot will accept all auxiliaries and arch wires used in Begg treatment and it performs as a typical Begg bracket in relation to tipping, bite opening, incisor and molar positioning, and torque. The appliance is set up in the standard manner with the 0.036 inch Begg tube placed gingivally on the first molars. All Begg slot heights, other than the molars, are dictated by the edgewise slot and, as such, are 1 to 1.5 mm. more gingival than in a routine Begg banding. It is absolutely essential to set up the straight wire slot so that on the straight wire series the wire is level from the molar tube to all other brackets. In clinical preparation, it is desirable to band the molars first. Slight variations in the dimension from molar tube to cusp tip will exist because of anatomic differences, but a cusp-tip-to-tube distance of 3.5 mm. is a desirable starting point. If 3.5 mm. is acceptable, then all other edgewise slots must also be at 3.5 mm. except those on the canines and lateral incisors. Upper and lower canine brackets are placed gingivally 0.5 to 1 mm. more, depending on tooth size and shape. Such a position promotes canine-protected occlusion. The upper lateral incisors are placed 0.5 mm. more incisally to free them from interferences on the working occlusal movements. Each tooth must receive the specific brackets designed for it so that angulation, torque, and the in/out compensation are correct (Figs. 8A and 8B). 31

The 1 to 1.5 mm. increased gingival positioning of the Begg slot does not seem to affect the bite-opening or tipping characteristics of Begg treatment. Free tipping is made very effective by means of a specially tapered bracket slot (Fig. 9). Also, special bypass pins and safety lock pins are available to reduce binding. The pins used are of a special length, since the width of some of the combination brackets is larger than a routine 256 bracket. The pin length is slightly greater in order to clear the tie wings of the edgewise part of the bracket, especially on the maxillary incisors. Begg molar tubes are kept gingivally and can be obtained with convertible straight wire tubes on the lower molar. The convertible tubes provide for desired Class II elastic hooks during Stages I, II, and III. They can be adapted to function as a routine straight wire type of bracket when the straight wire system is continued with first and second molars. It is not recommended that second molars be incorporated into the Begg system initially. All Begg treatment should be built around the first molar as the anchor unit, since experience shows that this is the most effective differential anchorage position and the most desirable for bite-opening mechanics of the Begg philosophy. After the bite is opened and retraction of incisors has been completed, the second molars can be banded without altering the anchorage or biteopening potential of the system. When the appliance is properly and accurately constructed, the system is set up so that all edgewise slots are positioned for accepting a straight arch wire. The angulation, tip, and torque are comparable to current straight wire systems. Ligation of the wire can be done routinely with ligature wire or elastic modules. The lower molar combination tube permits ease of passing from first to second molars. Headgear tubes are available if desired. Use of the edgewise portion of the bracket is not begun in most instances until late in Stage III. Clinical experience with the combination bracket indicates that the Begg portion of the bracket is highly successful and fulfills all the essentials of a true 256 type slot. The treatment procedures necessitate the use of pure Begg type principles when the Begg slot is being used. All arch wire forms, anchor bands, bypass bends, and elastic forces should be similar to a routine Begg treatment approach.12,24,40 Because of the difference in the physical characteristics of the bracket parts, any attempt to alter the Begg treatment principles by switching slots or forces is prone to problems and anchorage difficulty. All Stage I, II, and III objectives should be followed, and this can be done effectively only if free tipping is exercised within the Begg slot (Fig. 10). It is recommended that treatment be initiated with routine 0.016 inch round Australian wire (orange special plus) using 40- to 45-degree anchor bends and 2½ to 3 ounce Class II elastics. Vertical loop arches are still suggested as the initial wire if gross irregularity exists and bite opening is desired immediately. A free-tipping appliance is essential, and all recorded problems which can affect tipping and bite opening must be controlled.12,32,41 For the best physiologic response to the appliance, the Begg procedures should be carried completely through Stage I and Stage II and at least partly through Stage III. Routine 0.016, 0.018, and 0.020 inch round wires, toe in or out, anchor bends, and intra- and interarch elastics are used as recommended in Begg therapy. At the end of Stage II, the occlusion should show the typical Stage II characteristics: spaces closed, bite opened to an edge-to-edge relationship, molars Class I or better, incisors retracted and tipped lingually, all rotations and ectopically repositioned teeth overcorrected. Stage III is essential; the combination bracket is not intended as a substitute for this phase of treatment. When the occlusal relationship and treatment objectives are ready for Stage III, the severe tipping of the buccal segments and incisors, which is typical and characteristic of Begg therapy, produces a very irregular pattern to the angulated rectangular slots. The angulation is so severe in some cases that placement of leveling wires is contraindicated (Figs. 11A and 11B). Short interbracket distance between the edgewise slots increases force values and leveling forces. A common difficulty is the tipping of teeth mesially into a more bimaxillary relationship as seen in routine edgewise leveling procedures with full appliancing and no elastics or coil springs.40 The unwanted movement can be eliminated by undertaking adequate uprighting in Stage III to level the straight wire slots before a straight wire is placed (Fig. 12). 32

Stage III should be carried out with 0.020 inch base wires, constricted in the maxillary arch, and having reduced anchor bends in a typical Begg program. All Begg uprighting springs and torquing auxiliaries can be placed in the Begg slot with no difficulty. The Stage III mechanics should be continued until the occlusion approaches a fairly level plane and the edgewise slots are almost parallel. This is a subjective decision by the orthodontist, but clinically it seems to be within 5 degrees of the horizontal. When the alignment has reached this degree of leveling and uprighting, the Begg portion of treatment has ceased. The Begg wires and springs are removed and the remaining treatment is done in the rectangular slot with a straight arch wire. The new wires may be braided round, braided rectangular, nitinol, routine round, or edgewise wires up to 0.018 by 0.025 inch. Usually one braided or small round wire series is needed before a rectangular wire can be placed for final torque control. Some cases will require adjustments in the final rectangular wire to maintain proper anterior incisor torque. since Begg treatment has excellent torquing capability and the degree of torque is dependent on the clinician's decision, the predetermined amount of torque in the straight wire slot may be inadequate to meet the degree of torque established in Stage III by the orthodontist. If the standard 7-degree torque is thought to be inadequate to meet the clinician's needs, the torque for the incisors can be obtained in increased amounts as in other systems. We feel that banding of lower second molars is contraindicated by early Begg treatment because of the philosophy of mechanics involved in bite opening. Second molars are not used for anchorage or bite opening, and their use can even interfere with these functions because of the more distal placement of vertical forces and the reduction of the vertical extrusive component of the Class II elastics. Banding of second molars is, however, often essential for proper marginal ridge control, to improve the buccolingual position of the second molars, and to act in functional balance. These movements are best accomplished in late Stage III and with the rectangular straight wire mechanics. The second molars can be banded or bonded during Stage IV, and sectional 0.014, 0.016, or 0.018 inch wires can be used to begin leveling without interfering with Stage III. The second molars can be bonded or banded with routine straight wire tubes placed at the same occlusogingival positions as the first molar rectangular tube. Since the Stage III arches are in the round tube, the sectional auxiliary wires to level the second molars can be placed in the rectangular tubes. When the Stage III is removed and straight wire treatment initiated, the second molars are level and ready for incorporation into the finishing mechanics (Fig. 13). Some criticism of the rigid finishing procedures has come forth from a few Begg clinicians and others.22,37,38 Some believe that loose, free-tipping appliances are more desirable to encourage physiologic or functional settling of occlusion. The idea of a functional occlusal settling is good, but the rectangular finishing rigidity does not alter this concept. Optimum occlusal settling is possible only if the teeth are in their best three-dimensional position and in best relation to the functional paths. These are established most accurately with proper torque, uprighting, and arch form. When this is accomplished in the straight wire segment of the bracket, any finishing or band-removal technique is enhanced. Segmental band removal, positioners, or light 0.012 inch functional settling wires are all effective. Ideal finishing is completely dependent upon the best achievement of the Stage I, II, and III goals where the physiologic harmony of Begg treatment is produced. These stage objectives are designed to complement the tipping movements, force vectors, and force values of the appliance to Use freeway space and molar elevation, to retract incisors into a proper functional environment, and to establish the optimum anteroposterior position of the denture.25,30,31

We have observed additional favorable findings in the clinical application of the combination system. Changes in the amount of time required to accomplish specific stage objectives can vary when compared to traditional Begg treatment. Stage III can be altered because of the shortening of the usual uprighting periods by finishing the uprighting and torque in the rectangular slot. In Class I extraction cases, where Stage II closure may be minimal and uprighting of canines frequently amounting to only a few degrees, Stage III may be completely eliminated and only rectangular finishing may be needed. Use of the edgewise slot in one arch and the Begg slot in another arch provides the clinician with different anchorage and movement combinations where bodily movement and free tipping can be employed simultaneously. It is 33

also possible to reduce looped arches in Stage I by using sectional auxiliary arch wires, such as flexible twisted wire or nitinol leveling wires, in the edgewise slot on the four incisors to initiate alignment while the Begg base arch is used to obtain bite opening and retraction of canines and incisors. In nonextraction cases, Stage II and Stage III may be significantly shorter and possibly nonexistent because space closure in Stage II is usually minimal, uprighting is needed only on certain individual teeth, and torque requirements are reduced. It is often possible to enter the rectangular slot with the main wire very early in the nonextraction cases and to control most of the uprighting and torque with only the straight wire type of angulated and torqued slot. Another advantage of the combination system bracket is the potential in transfer of cases under treatment. Routine transfer of Begg cases to a few areas of the country is difficult because of the lack of treatment facilities and the scarcity of clinicians who have had experience with the technique. Frequently, patients are required to travel longer distances or to have appliances changed in order to continue treatment. In a combination system, an orthodontist can switch to a slot he feels best able to control. An astute edgewise clinician can go to the rectangular slot and, using appropriate anchorage design, sectional wires, etc., continue treatment with minimal inconvenience to the patient or the doctor. Clinical use of the combination Begg and straight-wire type of appliance has been very gratifying. The optimum treatment capabilities of two excellent treatment approaches are united in a common technique. The combination bracket appears to have good potential for clinical orthodontics. Much can be expected in new designs and combinations as the idea progresses. This article has been presented to familiarize clinicians with the principle. Perhaps it will stimulate others to seek improvements in design and techniques. I acknowledge, with thanks, The University of Florida Department of Orthodontics and Mr. Conrad Bamgrover and Mr. George Augur of Unitek Corporation for their assistance in obtaining some of the line drawings for this paper. I also thank Dr. William Baker for his assistance in the development of the combination bracket concept.

Ref Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1981 Jun (591 - 609): Begg and straight wire Thompson. -------------------------------1. Brodie, A. G., and Thompson, J. R.: Factors on the position of the mandible, J. Am. Dent. Assoc. 29: 925, 1942. 2. Aubrey, R. B.: Occlusal objectives in orthodontics, AM. J. ORTHOD. 74: 162-175, 1978. 3. Ingerwall, Bengt: Functionally optimal occlusion, the goal of-orthodontic treatment, AM. J. ORTHOD. 70: 80-90, 1976. 4. McHorris, W. H.: Occlusion with particular emphasis on the functional and parafunctional role of anterior teeth. Part I, J. Clin. Orthod. 13: 689-701, 1979. 5. McHorris, W. H.: Occlusion with particular emphasis on the functional and parafunctional role of anterior teeth. Part II, J. Clin. Orthod. 13: 608-620, 1979. 6. Parker, W. S.: Centric relation and centric occlusion— An orthodontic responsibility, AM. J. ORTHOD. 74: 481-500, 1978. 7. Roth, R. H.: Temporomandibular joint pain— Dysfunction and occlusal relationships, Angle Orthod. 43: 136-153, 1973. 34

8. Weber, F. N.: Clinical investigations related to the rise of the Begg technique at the University of Tennessee, AM. J. ORTHOD. 59: 24-36, 1971. 9. Williamson, E. H., Caves, S. A., Edenfield, R. J., and Morse, P. K.: Cephalometric analysis: Comparisons between maximum intercuspation and centric relation, AM. J. ORTHOD. 74: 672-677, 1978. 10. Andrews, L. F.: The straight wire appliance, origin, controversy, commentary, J. Clin. Orthod. 10: 99-114, 1976. 11. Barrer, H. G.: A survey of Begg treatment, AM. J. ORTHOD. 40: 494-506, 1963. 12. Begg, P. R., and Kessling, P. C.: Begg orthodontic theory and technique, ed. 3, Philadelphia, 1977, W. B. Saunders Company. 13. Magnus, B. W.: The straight wire concept, AM. J. ORTHOD. 73: 541-550, 1978. 14. Mulligan, T. F.: Common sense mechanics, J. Clin. Orthod. 13: 588-594, 1979. 15. Mulligan, T. F.: Common sense mechanics. Part II, J. Clin. Orthod. 13: 676-683, 1979. 16. Ricketts, R. M.: Bioprogressive therapy as an answer to orthodontic needs. Part I, AM. J. ORTHOD. 70: 241-268, 1976. 17. Ricketts, R. M.: Bioprogressive therapy as an answer to orthodontic needs. Part II, AM. J. ORTHOD. 70: 359-397, 1976. 18. Sims, M. S.: Conceptual orthodontics, AM. J. ORTHOD. 71: 431-439, 1977. 19. Thurow, R. C.: Edgewise orthodontics, ed. 3, St. Louis, 1972, The C. V. Mosby Company. 20. Andrews, L. F.: The six keys to occlusion, AM. J. ORTHOD. 62: 269-309, 1972. 21. Andrews, L. F.: The straight wire appliance, Syllabus of philosophy and technique, 1975, L. F. Andrews. 22. Meyer, M. M., and Nelson, G.: Preadjusted edgewise appliances: Theory and practice, AM. J. ORTHOD. 73: 485-498, 1978. 23. Begg, P. R.: Light arch wire technique employing the principles of differential force, AM. J. ORTHOD. 47: 30-48, 1961. 24. Begg, P. R.: The differential force method of orthodontic treatment, AM. J. ORTHOD. 71: 1-39, 1977. 25. Barrer, H. G.: Evaluation of the Begg technique 5 years later, Begg J. Orthod. Theory Treat. 3: 29-34, 1964. 26. Barton, J. A.: A cephalometric appraisal of cases treated with edgewise and Begg technique, Angle Orthod. 43: 11-126, 1973. 27. Daugremond, Chester: The Begg light wire treatment; a comparative study. Unpublished data, 1969. 28. Parker, W. S.: A consideration of the pure Begg technique, Angle Orthod. 39: 1-10, 1967. 29. Swain, B. F., and Ackerman, J. L.: An evaluation of the Begg technique, AM. J. ORTHOD. 55: 668-687, 1969. 30. Thompson, W. J.: A cephalometric appraisal of incisor positioning with the Begg appliance, Angle Orthod. 44: 171-177, 1974. 31. Thompson, W. J.: Occlusal plane and overbite, Angle Orthod. 49: 47-55, 1979. 32. Barrer, H. G.: Treatment problems, source and elimination, Begg J. Clin. Orthod. Theory 4: 59-64, 1968. 33. McDowell, C. W.: Static anchorage in the Begg technique, Angle Orthod. 39: 162-170, 1969. 35

34. McDowell, C. W.: A reappraisal of cephalometrics. Part I, J. Clin. Orthod. 4: 82-92, 1970. 35. McDowell, C. W.: A reappraisal of cephalometrics. Part II, J. Clin. Orthod. 4: 134-145, 1970. 36. Thompson, W. J.: Begg Stage IV, Begg J. Orthod. Theory Treat. 5: 17-24, 1969. 37. Begg, P. R.: Personal communication, January, 1980. 38. Dellinger, E. L.: A scientific assessment of the straight wire appliance, AM. J. ORTHOD. 73: 290-299, 1978. 39. Baldridge, Doyle: Leveling the curve of Spee: Its effect on mandibular arch length, J. Pract. Orthod. 3: 26-41, 1968. 40. Begg, P. R .: Choice of bracket for the light wire technique, Begg J . Orthod . Theory Treat. 1: 11-18, 1962. 41. Thompson, W. J.: Current application of Begg mechanics, AM. J. ORTHOD. 62: 245-271, 1972. 42. Williamson, E. H.: Occlusion: Understanding or misunderstanding, AM. J. ORTHOD. 46: 86-93, 1976. 43. Timm, T. A., Herremans, E. L., and Osh, M. A.: Occlusion and orthodontics, AM. J. ORTHOD. 70: 138-145, 1976.

36

Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1986 Oct (286 - 295): Nonextraction Begg treatment of Class II malocclusions - Meistrell, Cangialosi, Lopez, and Cabral-Angeles --------------------------------

A cephalometric appraisal of nonextraction Begg treatment of Class II malocclusions Malcolm E. Meistrell, Jr., D.D.S., Thomas J. Cangialosi, D.D.S., Jose E. Lopez, D.D.S., and Angelica Cabral-Angeles, D.D.S. New York. N.Y. Initial and final cephalometric evaluations are compared in a sample of 42 patients with Class II malocclusions treated in a nonextraction manner with the Begg appliance. The sample was analyzed as a group. Subgroups of patients with Division 1 and Division 2 characteristics were analyzed separately. To depict skeletal and dental changes, measurements were made using the sella nasion, palatal, and mandibular planes as reference planes. The findings show that on the average: (1) The upper first molar maintained its anteroposterior position at the same time that SNA was reduced. This suggests a restriction of anterior maxillary growth. (2) The mandibular first molar moved forward by 1.2 mm. Part of this change was attributed to anchorage consumption. (3) Vertical changes in both the maxilla and the mandible were found to be within the normal range. (4) No significant change in occlusal or mandibular plane angles was observed except for the Division 1 subgroup in whom a mild increase in the mandibular plane angle was observed. (AM J ORTHOD DENTOFAC ORTHOP 90: 286-295, 1986) A basic principle underlying the Begg treatment method is, "Occlusion is never static. It is in a constant state of flux.''1 Occlusion should change simultaneously in a horizontal direction (mesial migration) and a vertical direction (continuous eruption) throughout life. P. Raymond Begg based his philosophy of treatment on his studies of the occlusion of Australian aborigines. The corase diet of the aborigines abraded the teeth not only incisally and occlusally but also interproximally from the moment of their eruption into the dental arches. He concluded that the average loss of tooth mass as a result of attrition over the period of a lifetime was 14 mm. This has a tendency to prevent crowding as teeth migrate mesially. Attrition in modern man is minimal. In light of the horizontal and vertical changes that were observed in stone Age man's dentition, moving the maxillary dental arch distally in the correction of Class II malocclusion is biologically unsound, according to Begg. Although numerous articles in the orthodontic literature address different aspects of the Begg technique, it is evident that the use of this technique in the nonextraction treatment of patients with Class II malocclusions requires further clarification with regard to the movements that contribute to the Class II correction. REVIEW OF THE LITERATURE Originally, the Begg method was primarily an extraction technique. However, it has been observed that excellent results may be achieved using the Begg appliance for nonextraction treatment. In nonextraction treatment, some adjuncts to 37

Begg mechanics have been used, such as bite plates, extraoral force, lip bumpers, and the Margolis ACCO appliance. However, in 1975, Cadman2 reported nonextraction treatment without these adjuncts, using pure Begg mechanics. His indications far nonextraction treatment were minimum tooth movement required, maximum intraarch space or substantial freedom to reposition the lower incisors labially in relation to the A-Po line, the presence of a good skeletal pattern, a satisfactory relationship of tooth size to arch length, and good growth potential. If these factors are present, Cadman believed it should be possible to complete nonextraction treatment within profile and denture base requirements. The mechanics of nonextraction treatment are essentially the same as for extraction therapy with the exception of Stage II. During the second stage of extraction treatment, the excess extraction space is closed. In nonextraction treatment, there is usually little ar no residual space remaining so that Stage II is either very short or unnecessary. Cadman suggested that the premolars should be left unbanded early in treatment to permit their extrusion during bite opening in Stage I. Cadman theorized that unlike overbite correction by leveling with a full-banded appliance, the change from distocclusion to neutrocclusion occurs in less time and with less anchorage loss if premolars are free to adjust to the transitional occlusion. Any arch wire engagement of the premolars will interfere with occlusal correction because of increased cuspal interference, which impedes efficient bite opening and prolongs Class II elastic wear with resultant anchorage loss. Cadman did not support this with specific data. He advised banding of premolars for the alignment of rotations and marginal ridge heights at the end of Stage I. However, Barrer3 stated that all teeth should be banded, especially if the malocclusion is severe. Premolars are banded when the case requires a specific positional change such as rotation or alignment of marginal ridge heights. If premolars are not banded, he suggested placing an activated coil spring between the molar and canine. stage III is greatly reduced because extensive root positioning is not required. The use of Class II mechanics is minimized in the last two stages since it is needed only to maintain an edge-to-edge relationship of the anterior teeth. Therefore, anchor bends are reduced progressively as the need for elastic wear is decreased. In the Begg technique, anchorage is a function of arch wire design and degree of tip-back or anchorage bend. To quote Swain,4 One of the paradoxical but pleasant suprises of Begg nonextraction mechanics is that the anchorage potential is often enhanced if the anchor molars have a mesial axial inclination at the commencement of treatment. The combination of normal anchorage bend force with light Class II elastic force brings about a beneficial distal tipping of the molar crowns into an upright position. Provided that the force of the Class II elastics is sufficiently light, the lower as well as the upper molar crowns actually tend to move distally. This net distal movement occurs because, although the influence of the anchorage bend simultaneously tends to tip the crown distally and the roots forward, the resistance to crown tipping is low while the resistance to root tipping is high. Consequently, crown tipping occurs rapidly and root tipping slowly. Such net distal movement of mesially inclined anchor molars can be important in non-extraction treatment because it provides more arch length for teeth anterior to the molars.

One should consider the differential response to magnitude and duration of forces. Light Class II elastic forces should be used over the shortest period of time to prevent forward drag of the lower posterior teeth, keeping anchorage loss to a minimum. One to two ounces of elastic traction is usually sufficient. Rapid bite opening that results in minimal occlusal interference is helpful in the reduction of treatment time. Patient cooperation is imperative. Lastly, the rate, amount, timing, and direction of growth can be factors for a favorable result. Therefore, success depends on a delicate balance of anchorage control, the magnitude of Class II elastic force, and the duration of the force and growth, if present. Lateral cephalometric x-ray films taken before, during, and after treatment are useful in observing the changes that have taken place. Williams5 made a cephalometric appraisal of the characteristic responses of patients who had been treated 38

with the Begg technique. He observed the following: the lower incisors moved bodily lingually within the alveolar process of the mandible; SN-GoGn increased during the third stage; at posttreatment Point B moved forward as SN-GoGn decreased, reducing ANB; the occlusal plane angle increased more than SN-GoGN because the heights of the posterior and anterior teeth were influenced by treatment; and as SN-GoGn decreased, Ul and SN decreased. Ll to APo is critical to lip balance and overbite reduction is stable because of torquing of the maxillary incisors. Little can be found in the literature concerning changes taking place in nonextraction Begg treatment, specifically those changes that cause a correction from Class II to Class I. Cadman2 believed that there is distal tipping of the upper molar caused by the amount of anchor bend and the distal component of the Class II elastic force transmitted through the molar stop. He theorized that a restriction of normal maxillary growth was present. He also believed that the lower molar moved in an occlusal and slightly mesial direction because of the vertical and horizontal components of the Class II mechanics. Class II mechanics may also facilitate a functional positional change of the jaw. Napolitano6 made a similar study. His results showed distal movement of the upper molars and mesial movement of the lower molars. He concluded that growth and appliance manipulation determined his results. Levin7 in a review of the literature on treatment results of the Begg technique stated, "There is disagreement regarding the manner in which treatment changes are attained.'' OBJECTIVES OF THE STUDY The purpose of this study was to determine cephalometrically the changes that occur in the dentition and supporting structures during the correction of a Class II malocclusion to a Class I relationship with nonextraction Begg mechanics. It is expected that the findings obtained will provide a better understanding of the different factors affecting treatment, and give the clinician a better understanding of the technique and the proper indications and contraindications for its use. MATERIALS AND METHODS Forty-two patients treated at the clinic of the Orthodontic Department of Columbia University or at the private office of two of the authors were selected for this study. All patients had been classified as having Class II malocclusions. There were 23 girls and 19 boys in the sample. The age range at the start of treatment was 10 to 16 years with a mean of 12 years 9 months. The sample was not separated by sex because the rate of change with age for skeletal measurements used in the study is similar for both boys and girls.8 The molar relation ranged from a cusp-to-cusp relation to a full cusp, Class II relation. The overjet ranged from 0 to 14 mm with a mean of 6.5 mm and a standard deviation of 2.79 mm. Initially, first molars, canines, and anterior teeth molars were banded (or bonded if preferred). The arches were leveled and aligned with a multiple-loop arch wire or a plain arch wire with a coaxial auxillary wire if crowding was present. Anchorage bends were placed anterior to the molar tubes to initiate bite opening. If no bracket or cuspal interferences were observed, Class II elastics were started to consolidate interdental spaces in the maxillary arch and to begin anterior retraction. Otherwise, in order to conserve anchorage, Class II elastics should be delayed until the interferences are no longer present. As soon as anterior segments were leveled and aligned, and all maxillary interdental spaces were closed, Australian 0.016 inch plain arch wires were prepared making sure that the intermaxillary circles were against the canine brackets. At this stage the premolars were not banded or bonded. A piece of coil spring or plastic tubing may be placed between the molar tube and the canine bracket to maintain premolar space and to protect the cheek from irritation. The anchor bends were made of sufficient magnitude to carry the anterior segment of the arch wire to the depth of the muccobuccal fold when passive. Class II elastic traction in the range of 1 to 2 ounces was used. 39

Once Class I molar and canine relationships were achieved, the premolars were banded and engaged onto the arch wire. Subsequently, Stage III mechanics were instituted as required. A brief torquing period was usually necessary to establish the correct axial relationship of the maxillary central incisors. Initial and final cephalometric x-ray films were taken using a standard cephalometric technique. Pretreatment and posttreatment cephalometric evaluations were compared. The analysis consists of three separate groups of measurements. The first group used sella as registration point and the sella-nasion line as the reference plane. From this configuration the following angular measurements were recorded: sella nasion to Point A (SNA), sella nasion to Point B (SNB), the difference between SNA and SNB (ANB), the long axis of the most anterior maxillary central incisor to the sella-nasion plane (U1-SN), mandibular plane (a line drawn from Go to Gn) to the sella-nasion Plane (SN-MP), occlusal plane to the sella-nasion plane (SN-OP), the sella-nasion plane to pogonion (SN-Po), interincisal angle (U1-L1), and the distance in millimeters from the tip of the most anterior lower central incisor along a perpendicular to the line connecting Point A to pogonion (L1-APo). The second group of measurements used the palatal curvature as registration point and the palatal plane as the reference plane. For this purpose the palatal plane was defined as a Cartesian x axis, and the intersection between the palatal plane and the perpendicular line from the tip of the maxillary first molar of the initial headplate was defined as the origin. Relative to this system, the initial and final positions of the mesial cusp of the maxillary first molar were measured. Measurements were made in millimeters, perpendicular and parallel to the palatal plane, to determine the X and Y coordinates. The third group of measurements was made using the mandibular symphysis as registration and the mandibular plane as reference plane. Again the reference plane (mandibular) was used as the Cartesian x axis and the intersection between the mandibular plane and a perpendicular line to the tip of the mesial cusp of the lower first molar of the initial headplate was defined as the origin. Relative to this position, the initial and final positions of the tip of the mesial cusp of the mandibular first molar were measured perpendicular and parallel to the mandibular plane (X and Y coordinates) in millimeters. All measurements were made for each of the 42 cases whenever possible. The computations were made for the whole sample group and for a 15-case subgroup of Class II, Division 1 malocclusions and a 10-case subgroup of Class II, Division 2 malocclusions. The data were analyzed using a DEC 10 computer and the SPSS program. Mean, standard deviation, standard error, and t test for the difference of the means between initial and final values were computed for all angular measurements and for the difference in X and Y positions for upper and lower first molars. In addition, each cephalogram was superimposed on millimeter graph paper. To make the superimposition, sella was defined as the origin (point o,o) and the sella-nasion plane was defined as the x axis. X and Y coordinate values were recorded for each of the following landmarks: nasion, anterior nasal spine, posterior nasal spine, Point A, Point B, tips of the crown and root of the most anterior maxillary central incisor, tip of the mesial cusp of the maxillary first molar, tips of the crown and root of the most anterior mandibular incisor, tip of the mesial cusp of the mandibular first molar, pogonion, gnathion, and gonion. The values of the X and Y coordinates for each of the landmarks were averaged in total, and for Division 1 and Division 2 subgroups separately. These averages were used to construct composite graphic representations of the changes that occurred during treatment. RESULTS Figs. 1 and 2 graphically summarized Table I, which shows the changes observed in the relationship of the maxillary and mandibular first molars to their respective basal bones. 40

Table II shows the average changes computed for each of the measurements using the complete sample of 42 cases. Tables III and IV show the average changes for the Class II, Division 1, and Class II, Division 2 subgroups, respectively. Fig. 3 is a composite graphic representation of the average changes that were recorded for the complete sample. Figs. 4 and 5 are composite graphic representations of the average changes observed in the Division 2 and Division 1 subgroups, respectively. As may be observed, the maxillary first molar had an average change of 0.22 mm mesially. The standard deviation was 2.24 and the range was 5.0 mm distally to 5.0 mm mesially. The maxillary first molar had a mean movement of 2.1 mm occlusally or away from the palatal plane. The standard deviation was 2.32 mm with a range of 6.0 mm gingivally to 9.0 mm occlusally. The mandibular first molar showed an average change of 1.2 mm mesially. The standard deviation was 2.76 mm and the range was 7.5 distally to 7.0 mm mesially. The mandibular first molar had a mean occlusal movement of 2.6 mm. The standard deviation was 3.01 mm and the range was 6.0 mm gingivally to 9.0 mm occlusally. There was a mean decrease in SNA of – 0.73° with a standard deviation of 2.77 and standard error of 0.43. The t value was 1. 73, indicating a nonsignificant change in SNA with P = 0.091. SNB displayed a mean increase of 0.58° with a standard deviation of 2.22 and a standard error of 0.34. The t value was 1.71 with P = 0.096, indicating the change in SNB was not significant. However, the mean change in the ANB angle of – 1.27 with standard deviation of 2.27, a standard error of 0.35, and a t value of 3.64 (P = 0.001) shows a statistically significant change for the entire sample. The change in the ANB angle was not significant for the Division 1 subgroup, but was statistically significant in the Division 2 subgroup (P = 0.008) (Tables II, III, and IV). As shown in Table II, the average initial value for Sn-GoGn was 28.69°. The average final value was 28.61°. This value shows a nonsignificant difference of – 0.08° with standard deviations (SD) of 5.69 and 6.46 for the initial and final values, respectively. The standard errors (ER) were 0.00 and 0.99. The Student t test gave a value of 0.16 and P = 0.876. The average change in the mandibular plane angle in the Division 1 subgroup, as presented in Table III, was 1.2° with a standard deviation of 2.5 and a standard error of 0.6. The Student t test value of 1.91 indicates a nonsignificant change (P = 0.077). The Division 2 subgroup had a mean change in the mandibular plane angle of – 0.05°. The Student t value was 0.05 (P = 0.077), indicating that the change was not significant. The SN-OP angle had an average change of – 0.37°. Student t value of 0.63 failed to show a significant change with treatment (P = 0.531). The average change in the Division 1 subgroup was 1.5°. The Student t test value of 1.85 shows a nonsignificant increase (P = 0.085). The Division 2 subgroup also showed a nonsignificant change of 0.2°. The t value was 0.12 (P = 0.909). The SN-Po angle, which was used as an indicator of growth during treatment, had a mean change for the entire sample of 0.92° with a standard deviation of 1.79, a standard error of 0.27, and a t test value of 3.32 (P = 0.010). This change is statistically significant. However, the changes found for SN-Po for the Division 1 and Division 2 subgroups were not statistically significant. See Tables III and IV. The maxillary central incisor did not show a statistically significant change in relation to SN for the total sample (P = 0.537). However, when the individual subgroups were examined, there were significant changes in U1-SN. The change for the Division 1 subgroup was – 5.03 with a standard deviation of 5.19, a standard error of 1.34, and a t value of 3.76 (P = 0.002). The change in the Division 2 subgroup was 9.25 with a standard deviation of 8.34, standard error of 2.64, and a t value of 3.51 (P = 0.007). See Tables III and IV. The mandibular incisors showed statistically significant changes in both their angular relations to the mandibular plane and their spacial relations in terms of the A-Po line. For the entire sample, L1-MP increased 3.67° with a standard 41

deviation of 6.49, standard error of 1.00, and a t value of 3.66 (P = 0.001). The change for the Division 1 subgroup was 3.87° with a standard deviation of 6.16, standard error of 1.59, and a t value of 2.43 (P = 0.029). The Division 2 subgroup increased 5.40° with a standard deviation of 6.35, standard error of 2.01, and a t value of 2.66 (P = 0.025). The spatial relation of the mandibular incisors changed significantly for the entire sample. L1-APo increased 1.68 mm with a standard deviation of 2.38, standard error of 0.37, and a t value of 4.58 (P = 0.0001). The Division 1 subgroup showed an increase of 1.77 mm with a standard deviation of 2.57, standard error of 0.66, and a t value of 2.66 (P = 0.019); the Division 2 subgroup showed an increase of 2.4 mm with a standard deviation of 2.22, standard error of 0.70, and a t value of 3.42 (P = 0.008). See Tables II, III, and IV. The interincisal angle showed a statistically significant change only in the Division 2 subgroup. The mean decrease was 11.95° with a standard deviation of 12.32, standard error of 3.89, and a t value of 3.07 (P = 0.013). See Table IV. The Holdaway soft-tissue angle showed a statistically significant change only in the main sample (P = 0.11). See Tables II, III, and IV. DISCUSSION One of the most common criticisms of the Begg technique is that, because it relies heavily on Class II elastics and because of the use of light wires and anchor bends, extrusion of the posterior teeth and changes in the occlusal and mandibular planes are normal side effects of treatment. These effects have been especially attributed to the nonextraction approach. This study was undertaken in an attempt to provide reliable evidence relating to this controversy. Changes in relation to the upper and lower first molars The small forward change of 0.22 mm observed in the maxillary first molar suggests that the molar remains in its same anteroposterior relationship to the maxilla. It seems that the force of the anchorage bend and of the Class II elastics was not sufficient to distally drive the molar. It is interesting that the vertical change of 2.1 mm did not differ significantly from the 1.8 mm normal vertical change reported by Riolo and associates 8 for such a mean age and period of time in their study of normal patients. Cangialosi and Meistrell9 in a series of 18 extraction cases showed an extrusion of 0.86 mm, which was not statistically significant. The changes associated with the mandibular first molar include a 2.6 mm occlusal change (extrusion) that is the same as the 2.6 mm reported by Riolo and associates. In a study of 20 cases treated with Begg mechanics, Menzes10 showed an average extrusion of the mandibular molar of 2.87 mm. The forward 1.2 mm movement may be explained as closure of the leeway space, closure of existing space in the mandibular arch, and/or loss of anchorage. In the middle the anchorage bend, when properly combined with Class II elastics, exerts a translative moment/force ratio that effectively minimizes anterior dental displacement. This, in conjunction with minimal Class II elastic force within the range of 1 to 2 ounces on each side, prevents excessive mesial migration of the lower anterior teeth. These findings do not support the theory that mandibular molar extrusion is a consistent sequela of treatment. Changes in position of mandibular incisors The mandibular incisors, as observed from the findings of their relationship to the A-Po line, were consistently proclined. Edler11 also showed a proclination of the lower incisors with an increase of 8.5° in the incisor-mandibular plane angle and a 1.6 mm forward positioning with regard to the A-Po line. Cain12 showed a 1.2 mm anterior change. This is in contrast to the findings of Thompson.13 However, his sample was composed of extraction as well as nonextraction cases, which would account for his finding that the lower incisor consistently approached the A-Po line during treatment. No attempt was made during treatment to restrain mandibular anchorage consumption other than the use of the previously mentioned light Class II elastic forces. It is possible that the use of lingual crown torque-labial root torque could have decreased the labial repositioning of the mandibular incisor in relation to the A-Po line and the increase in the incisormandibular plane angle. 42

Changes in relation to mandibular plane The average change in the mandibular plane angle was – 0.08°. A Student t test of 0.16 (P = 0.876) suggests that on average the cant of the mandibular plane was not affected by therapy. This may be graphically observed in Fig. 3. The average change in the mandibular plane angle in the Division 1 subgroup, as may be observed from Table III, was 1.2° with a standard deviation of 2.5 and a standard error of 0.6. The Student t test value of 1.91 (P = 0.077) indicates a nonsignificant change. This finding, although small, suggests that care should be taken in using this type of therapy in high mandibular plane angle cases. To control this tendency, the magnitude of the Class II elastics must be maintained within the range of 1 to 2 ounces of force. All interferences from brackets or cusps must be avoided. This was not observed, however, in the Division 2 subgroup. In this group the average change in the mandibular plane angle was 0.05°. See Table IV. Changes in relation to occlusal plane The cant of the occlusal plane also showed a great degree of stability during treatment. The average change recorded was – 0.37°. A Student value of – 0.63 failed to show a significant change in the inclination of the occlusal plane (P = 0.53). This is compatible with the findings in relation to the mandibular plane. In contrast, Hocevar14 has stated that conventional Begg Stage III mechanics tend to rotate the occlusal plane downward anteriorly and upward posteriorly. This can be countered by the use of anterior anchor bends and posterior check elastics if necessary.

Because no significant extrusion of the maxillary and mandibular molars was observed, these findings suggest that deep overbite may be mainly corrected by intrusion of both maxillary and mandibular incisors. It also suggested that molar extrusion was positively coordinated in such a way that the stability of the occlusal plane was maintained throughout growth. It is interesting to note that although the change in SN-OP was not statistically significant for this sample of nonextraction cases, O'Reilly15 noted a significant increase for a sample of 24 extraction cases. Nonsignificant changes were also found in the Division 1 and Division 2 subgroups. See Tables III and IV. Changes in relation to bony facial profile The SNA angle was decreased by 0.74°. At the same time SNB was increased an average of 0.58°. The summation of these two changes when rounded to the nearest tenth brought about a reduction of 1.3° in the ANB angle. This change was statistically significant (P = 0.001). It appears that at the same time that anterior maxillary growth was restrained, the mandible was allowed to grow freely. Cohen16 and Hanes17 reported significant distal movement of Point A. However, Cohen reported that Point B moved distally. In contrast, Hanes reported that the use of Class II elastics tended to nullify the undesirable distal movement of Point B. The results of this study correspond with the results of Hanes. Possible mechanism of action The data reported suggest that the nonextraction Begg treatment of Class II malocclusion exerts a multifactorial influence on dental and skeletal tissues. Therapy seems to restrict maxillary anterior growth without changing the cant of the occlusal plane while allowing full mandibular growth without greatly increasing the mandibular plane angle. To a great extent, part of the correction seems to be caused by a positive coordination between therapy and favorable growth. 43

The maxillary molars, based on these findings, appear to have stayed approximately in their original spacial relationship to the cranial base. At the same time, the lower molars moved forward an average of 1.2 mm. This forward movement may be explained by the closure of some original interdental spaces, closure of the leeway spaces, correction of rotations, and loss of anchorage. The forward movement and tipping of the lower incisors is related to these changes in addition to leveling the arch and correction of anterior crowding. Vertically, the changes appear to be coordinated with growth in such a manner that little or insignificant changes were found to occur to the cant of the occlusal and mandibular planes. The difference between the direction of maxillary and mandibular molar eruptive processes, however, may also account for part of the change in molar relation from Class II to Class I. In measuring Sn-Po at the beginning and end of treatment, it is apparent that a significant amount of mandibular growth took place during treatment, which when added to the factors mentioned contributed to the correction from Class II to Class I. CONCLUSIONS The data reported from this study provide information regarding the factors that are responsible for the correction of Class II malocclusion to neutrocclusion using the Begg appliance. Indications and contraindications are suggested based on observed secondary effects. The following conclusions were made: 1. Forward maxillary growth appeared to be restrained because the SNA decreased and the maxillary molars did not move forward significantly. 2. Conversely, forward growth of the mandible occurred as expressed by the forward movement of Point B, which resulted in an increase in the SNB angle. Forward mandibular growth is also indicated by an increase in the angle SN-Po during treatment. 3. Vertically, treatment and growth appeared to be coordinated in such a way that stability of the mandibular and occlusal planes was observed. 4. The measured changes in vertical position of the upper and lower first molars was well within the range of expected change resulting from normal growth. 5. It appears that correction from Class II to Class I occurred as a result of the factors mentioned previously in conjunction with the direction of vertical eruptive path and forward mandibular growth.

Ref Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1986 Oct (286 - 295): Nonextraction Begg treatment of Class II malocclusions - Meistrell, Cangialosi, Lopez, and Cabral-Angeles. -------------------------------1. Begg PR: Stone age man's dentition. AM J ORTHOD 40: 298-312, 1954. 2. Cadman GR: Nonextraction treatment of Class II, Division 1 malocclusion with the Begg technique. AM J ORTHOD 68: 481-498, 1975. 3. Barrer HG: Non-extraction treatment with the Begg technique. AM J ORTHOD 56: 365-378, 1969. 4. Swain BF: Begg series. 6. Non-extraction treatment with the Begg technique. J Pract Orthod 3: 67-81, 1969. 44

5. Williams R: The cant of the occlusal and mandibular planes with and without pure Begg treatment. J Pract Orthod 2: 496-505, 1968. 6. Napolitano J: Class II Division 1 Begg non-extraction. Thesis for orthodontic certificate, Columbia University, 1976. 7. Levin EF: Treatment results with the Begg technique. AM J ORTHOD 72: 239-260, 1977. 8. Riolo M, Moyers RE, McNamara JA Jr, Hunter WS: An atlas of craniofacial growth, Monograph 2, Craniofacial Growth Series, Ann Arbor, 1974, Center for Human Growth and Development, University of Michigan. 9. Cangialosi TJ, Meistrell ME: A cephalometric evaluation of hard- and soft-tissue changes during the third stage of Begg treatment. AM J ORTHOD 81: 124-129, 1982. 10. Menezes DM: Changes in tooth position and vertical dimension in severe Class II Division 1 cases during Begg treatment. Br J Orthod 2: 85-91, 1975. 11. Edler RJ: The effects of Begg treatment on the lower labial segment in Class II cases. Br J Orthod 4: 123-130, 1977. 12. Cain P: Anchorage preservation in non-extraction Begg technique. Thesis for orthodontic certificate, Columbia University, 1979. 13. Thompsom WJ: A cephalometric evaluation of incisor positioning with the Begg appliance. Angle Orthod 44: 171-177, 1974. 14. Hocevar RA: Orthodontic force systems: Technical refinements for increased efficiency. AM J ORTHOD 81: 1-11, 1982. 15. O'Reilly MT: Treatment and posttreatment changes with the Begg appliance. AM J ORTHOD 75: 535-547, 1979. 16. Cohen AM: Skeletal changes during the treatment of Class II/I malocclusions. Br J Orthod 10: 147-153, 1983. 17. Hanes RA: Bony profile changes resulting from cervical traction compared with those resulting from intermaxillary elastics. AM J ORTHOD 45: 353-364, 1959.

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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Mar(174 - 198): Technique Modifications to Achieve Intrusion of the Maxillary Anterior Segment

Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Mar(174 - 198): Technique Modifications to Achieve Intrusion of the Maxillary Anterior Segment --------------------------------

Technique Modifications to Achieve Intrusion of the Maxillary Anterior Segment DR. ANE TEN HOEVE DR. ROBERT M. MULIE DR. SIDNEY BRANDT There is a growing conviction and understanding of the limitations of certain tooth movements, particularly the repositioning of roots within the confines of the maxillary alveolar process. The studies of Edwards, Mulie and Ten Hoeve have broadened our knowledge and seem to indicate there is a narrowing of the anatomical areas within which orthodontists can move the roots of incisors. To place this concept in its proper perspective, it is necessary to refer to clinical observations. In Stage III, (Begg technique), the maxillary incisors which had been tipped lingually as a direct objective of treatment, now must have their roots uprighted. As these are lingualized, they frequently elongate, aided by the vector of the pull of Class II elastics. Torquing assemblages are then applied, to reposition the roots of the maxillary incisors lingually. There are various types and shapes of these sectionals that are designed to accomplish this important and necessary tooth movement. Many 46

operators assume and have assumed there would be an automatic and favorable response to their mechanotherapy, especially if the Stage III procedures were completely and carefully done in accordance with the technique requirements. The fact is that many times, such favorable responses are not attained. The axial inclinations of the incisors remain unfavorable, in spite of the attention devoted to proper mechanotherapy. In some instances, if the axial inclinations did seem improved, later studies indicated this did not happen by the roots being displaced lingually, but the crowns coming forward. These studies indicated there had been little or no true lingual root torque. Why are there such unfavorable responses? What causes some incisors to torque properly as anticipated and desired and, in other cases, nothing seems to happen to improve the long axis relationships, even when the mechanics used are similar. This can be especially frustrating and disappointing if the technique had been carefully attended to. One possible explanation to this problem could be anatomical. As the maxillary incisors become lingualized and extruded, the apical portion of the root may approximate the lingual palatal cortex, which consists of dense bone. The recent studies of Edwards17, Ten Hoeve and Mulie18 indicate that once this anatomical landmark is reached, there are strict limitations on future lingual apical root movement. From a practical, clinical viewpoint, this means that continued attempts at lingual root torque of apices that approximate the palatal cortex may be a questionable and sometimes a dangerous procedure. Ten Hoeve and Mulie18 have done studies utilizing laminagraphy and concluded the lingual palatal cortex will bend and will remodel, but will not allow the root apex to move lingually significantly. The root tip remains relatively stationary and the crowns will move anteriorly. The same study also reveals when the apical portion of the root is against the dense cortical plate, root resorption is a probable occurrence. Note - This anatomical barrier and limitation on tooth movement refers to root apices. The remainder of the tooth can be moved readily within the alveolar process. The Role of Intrusion To translate all these findings into useful, clinical, chairside procedures, it is logical that mechanotherapy be directed in several directions, of which greater use of the maxillary alveolar process is paramount. It is wise to intrude the maxillary incisors to a significant degree prior to any retraction. If this is accomplished, several advantages are immediately gained; 1. Bite opening is attained by moving maxillary incisors into the alveolus. 2. The potential for increasing a "gummy" smile is minimized. 3. The unfavorable tipping of the occlusal cant will not be as common. 4. There will be a reduction in the total amount of Class II elastics that will be required. 5. It will minimize the chances of moving the apices into juxtaposition against the dense cortical bone. 6. The chances for root resorption are diminished. 7. The need for lingualizing maxillary incisors will be lessened. 8. Torquing requirements will be reduced, and when needed will be accomplished within a more adequate anatomical area, and not restricted by the lingual cortical plate. 9. It will be easier to gain a Class I relationship of the maxillary cuspids. The entire concept of intrusion of teeth is still controversial. Some investigators suggest intrusion is unwise, impractical or unstable. Others claim such tooth movement is possible in the maxillary arch, but not in the mandible. There are those who teach intrusion of both maxillary and mandibular anteriors. Published reports in the literature1 indicate some 47

histological evidence of intrusion. McDowell2, after analyzing the fiber arrangement within the periodontal membrane concluded that it was impossible to intrude a tooth in its long axis. He believes that in order to depress a tooth, it is essential to include a lateral pressure. McDowell also writes, on a theoretical basis, a light continuous tipping force was the optimum way to achieve intrusion. Dellinger3 is probably the first to demonstrate intrusion histologically and cephalometrically. This was accomplished on monkey premolars. He applied a controlled force of 50 grams and attained 2.9 millimeters of intrusion, with very little resorption, and some compression at the apical region. Along the root surface, the periodontal ligament was in a state of tension and thickened, while new trabeculae were being formed. Stenvik and Mjör4 investigated the effect of intrusion on pulps and dentin of human premolars. They observed vacuolization in the odontoblastic layer and a reduction in the width of the predentin zone. Force levels above 150 - 200 grams caused a stasis in the pulp vessels. In their long range observations they concluded vacuolization was reversible. Reitan5 also did studies on the intrusion of human premolars and concluded that forces in the 80 - 90 gram range caused some apical root resorption, while any force not exceeding 30 grams did not result in any damage. If one were to judge the importance of intrusion by the number of histologic studies published in the literature, it would appear this specific tooth movement did not occupy a prominent place in orthodontic therapy. Magill6 in 1960, stated that intrusion of incisors was necessary for overbite correction, and to compensate for the increased overbite tendency that is apparent when incisors are retracted (Fig. 1). Poulton7, in a series of articles on headgears, correlated the interrelation of occlusal plane tipping and the position of pogonion. His reasoning was, by intruding the maxillary incisors with an anterior high pull headgear, there was control over the occlusal plane inclination and the mandible could continue its forward growth. Within this framework of treatment, esthetics was enchanced. In his report on Tweed mechanics and directional forces, Merryfield8 emphasized that when maxillary incisors were being retracted with Class II elastics, an anterior high pull headgear was advisable to prevent the anterior segment from becoming extruded. Thus, esthetics would be improved and the torquing requirements lessened. Ten Hoeve and Mulie18 have confirmed this concept with their laminagram studies. It does appear that orthodontic techniques are not always successful in attaining the objective of intruding incisors. Cephalometric investigations9,10 into cases treated with Begg and edgewise appliances reveal that with both techniques the upper incisors became extruded while being retracted. Ever since Ten Hoeve and Mulie did their laminagram studies on malocclusions treated with the Begg technique, it became more apparent and advisable to concentrate on the vertical control of the upper incisors. Claims11 have been made that with the pure Begg technique the maxillary anteriors are either intruded or held stable in a vertical position relative to the nasal floor. In fact, many orthodontists who treat with Begg appliances have noticed elongated upper incisors and tend to confirm the observation by Cadmun12, "The Begg technique does not lend itself to intrusion of the maxillary anterior teeth". A possible explanation for these differing opinions may be in the interpretation of at what level the incisor teeth should be kept during retraction. If the incisor is retracted along a line parallel to the palatal plane, it will become necessary to effect a significant amount of intrusion (Fig. 1). If there is failure in providing this intrusion during retraction, then the tooth is moving backward along a line parallel to the palatal plane, or even beneath this plane which is worse. In such circumstances, the maxillary incisors do not contribute towards bite opening and in fact, they contribute towards increasing the overbite. This will also result in the downward tipping of the occlusal cant. The incisal edge will slide along a line parallel to the palatal plane. The anteriors will be stable relative to the palatal plane that extends to the molars and beyond. This has been termed "relative extrusion". At the Department of Orthodontics, University of Groningen, two studies were made on the vertical changes that occur during treatment of malocclusions with the Begg technique. Bijlstra13 noted an increase in the distance from the palatal plane to the tip of the maxillary incisors, but concluded these teeth were held at about the same "vertical level" during 48

retraction. Levin14 reported there was no intrusion of the upper incisors. He indicated there is an increase in the distance from the palatal plane to the incisal tip and believes this is caused by tipping with Class II elastics. It is the authors' recommendation that the vertical position of the maxillary incisors should be related to the alveolar housing within which these teeth are to be moved, and to the original occlusal plane of the upper dentition. Therefore, we conclude that intrusion of the maxillary incisors is essential either prior to or during retraction (depending upon the type of malocclusion being treated) for anatomical and esthetic reasons. When the Begg technique is applied, the mandibular incisors can be intruded readily, if the roots are centered properly within the symphysis. Depression of the maxillary incisors is far more difficult to accomplish. Mechanics of Anchorage Bends These facts triggered an investigation into the mechanics of anchorage bends. An understanding of this adjustment is considered essential. Sims refers to the anchorage bend as that component of the Begg appliance that makes a major contribution to the success or failure in attaining treatment objectives. Swain16 measured the forces exerted by an anchorage bend. He concluded there was an extrusive force at the mesial end of the buccal sheath that equalled the intrusive force at the distal. It is generally assumed that molars are elevated as a reaction to the anchorage bend, but are somewhat restrained by the forces of occlusion. Sims15 when discussing reciprocal orthodontic phenomena makes an interesting observation. The anchorage bends have an intrusive action on the molars and the incisors. He attempts to take advantage of this as a counteraction to the extrusive vector of the Class II elastics. The clinician should recognize there are a vast variety of responses on molars from anchorage bends. These are caused by the angulation and location of the bends, the length, shape and position of the buccal sheaths, etc. Interest in what force (in grams) on a molar means in its actual displacement resulted in a series of experiments. These were done on a typodont, especially made for these tests. An acrylic block was fabricated, into which the six anterior teeth were processed, making them immobile. The premolars and molars were set into wax (Fig. 2). The acrylic block can be seated into a precise position on the base of the holder. Directly above and parallel to one quadrant, a series of holders and wires were constructed from which it becomes possible to attach elastics from different directions and distances to the molars. A frame was made that could hold a dental x-ray film (3 ´ 2½ inches). This frame can be seated lingual and parallel to a quadrant. This makes it possible to utilize standard x-ray films (Fig. 3). The open slits along its sides are used for aid in superimposition. Careful attention was directed to seating premolars and molars into the wax in the same manner and position for each experiment. Although many tests that resembled clinical experiences were completed, only those essential to this paper will be described . Experiment #1 Anchorage bends of 40° were placed distal to the second bicuspid cusps. When the archwire was slid into the buccal tubes the anterior portion rested in the artificial mucobuccal fold. The sheaths used in this test were prefabricated units, 4 mm long, and 0.9 mm inside diameter. The archwire was pinned and the typodont placed into a warmed oven for 10 hours. There was an overall extrusion of 2 millimeters, and the mesial ridge elevated slightly higher (Fig. 4). Although the mesial and distal edges were hardly displaced in the saggittal direction, the apices slid forward 2 millimeters. This indicates an "intrusive action" of the archwire distal to the anchorage bend. That this doesn't actually show an intrusion is due to the anchorage bend moving forward 1.5 millimeters and upward 3 millimeters, thus raising the molar. The conclusion is the anchorage bend did not tip the crown distally, but did bring the root apices forward. This anchor bend, within this kind of action, will have little or no effect upon intruding incisors. Experiment #2 This test is to determine the effect of bringing the 40° anchor bend closer to the buccal sheath. First, the results after five hours within a warmed oven were noted. After that, there was a reactivation of 10 degrees followed with an additional five hours of warming. The superimposition (Fig. 5) demonstrates that in the first period an elevation of the mesial ridge 49

occurred, but not by the forward movement of the anchorage bend. The crisp bend, being so close to the tube makes it less likely for an easy sliding through the sheath. Although the distal ridge remained at practically the same level, the distal apex was elevated and slid forward. It is believed this mesial movement of the apices is the result of the "intrusive action" of the anchorage bends. Since the wire could not slide forward freely, the action of the bends exercises its effect quickly by tipping the crown distally and moving the apices mesially (by the "intrusive action"). Following the reactivation (10 degrees) the anchorage bend relaxed partially with some forward movement, because of the angulation of the tube obtained in the first phase of this experiment. The result here too was a general elevation, as in Experiment #1, although more marked mesially. In the second phase the mesial and distal ridges were not displaced distally, but their apices were slid forward. Thus it is apparent again, the archwire distal to the anchor bend exerted an "intrusive force". In the overall comparison, it is interesting to note that the distal ridge is hardly raised, and yet the distal apex is elevated 3 millimeters. It seems evident that excessive anchorage bends cause the crown to be displaced distally. In the earlier stages of treatment, with such an anchorage bend, some intrusion of incisors can be expected. However, just as soon as the archwire can glide forward, this intrusive force will become diminished. Experiment #3 Having moved the bend closer to the sheath, it is feasible to make a much smaller anchor bend to have the anterior portion reach the mucobuccal fold. That was done in this experiment. Fig. 6 shows the superimposition. It appears that now the fulcrum is at the distal cusp. The mesial cusp is raised 1 millimeter and the apices are displaced mesially. This too is attributed to the "intrusive action" of the archwire, distal to the anchorage bends. Swain measured the force levels up to 130 grams at the mesial end of a buccal sheath, when pinning an archwire and it is rather remarkable with this force described, such a small amount of elevation actually occurs at the mesial ridge. It is probable the elevation can be controlled by the forces of occlusion. Experiment #4 For further evaluation, Class II elastics are added to the experiments. These elastics were attached to a mesial hook on the buccal sheath. The molars extruded an additional 3 millimeters after 10 hours in the oven, with an intermittent activation. The interesting observation was the anchor bends did not move forward at first, the apices were farther forward than in the first experiment, and the crowns were transposed mesially only 1 millimeter. The conclusion was the Class II elastics tended to keep the wire in direct contact within the tube, therefore the wire could not slide forward as it did in the first experiment. Now, as the anchor bend "relaxes", it effects a significant amount of incisor intrusion. This may offer a more valid explanation of why, in the Begg technique, the mandibular molars have been able to provide a base from which incisor intrusion could be attained. The maxillary molars do not have the same mesial force to keep that type of contact of the wire within the sheath. In addition, Class II elastics exert an almost vertical force. This is especially evident when the jaws are apart. The net effect is an elevation of the mesial mandibular molar ridge and extrusion of the maxillary incisors. Experiment #5 To investigate the concept of the wire contacting the inner surfaces of the buccal tubes, an experiment was done with sheaths that were 6 millimeters long. The anchorage bend was located in the same place as in Experiment #3. Since the tube was longer, a smaller bend would still have the anterior portion of the archwire reach the mucobuccal fold. In a further effort to mimic occlusal forces, a ligature wire was tied loosely around the archwire and bicuspid. The superimposition in Fig. 7 indicates the fulcrum is at the mesial cusp, while the distal cusp is actually intruded and the apices moved far forward, while remaining at the same vertical level. The bifurcation has been displaced mesially, giving evidence the fulcrum is at the mesial cusp. The apices moved mesially more than in any other experiment. The conclusion is that all the intrusive force of the wire distal to the anchorage bend expressed their action in the manner just described. 50

The anchor bend did not slide forward. It just became slightly elevated in reaction to the new angulation of the tube. Thus it seems that Sims15 observations that anchorage bends cause the molars to depress is valid, provided they have been carefully positioned. It is interesting to note that Dellinger3 conducting intrusive experiments on bicuspids in monkeys, used a sectional archwire from the molars resembling an anchorage bend and was surprised not to find any extrusion of the molars, but they did intrude. The sectional was not free to slide. The design of the anchorage bend is such, there will always be an extrusive force at the mesial end of the sheath. The extent of the force will depend upon the location and the degree of the anchor bend (Fig. 8). Any inherent excess of force may be counteracted by a bicuspid ligature, occlusal forces or by the anterior teeth beginning to intrude. There will always be an intrusive force on the distal end of the tube. This force will tend to depress the molar apices and move them mesially. The experiments described, plus earlier clinical experiences, convinces us that it is this force that causes the tube to be reangulated; that subsequent reactivations of the anchor bends cause an elevation of the molars and a diminishing intrusive action on the incisors. To summarize this passage, it is our conviction that control over the vertical dimension of the molar is not lost by distal crown tipping, but by the mesial displacement of the roots. These are different entities, and the clinician should be able to control these to the patient's benefit. Experiment #6 At this point a vertical elastic was attached to a hook soldered over the distal end of the tube, extending occlusogingivally. The purpose of this elastic is to counteract the intrusive action on the distal portion of the anchor bend (Fig. 9). The result is an insignificant amount of mesial root displacement and no elevation of the molars. Here too, the mesial cusp acts as the fulcrum. If a Class II elastic is added to the distal hook, along with the vertical elastic, mesial root movement is counteracted even more forceably. When the bend was reactivated, it was evident that very little of the force within the bend had been dissipated. This simply presented too much force mesially or resulted in a similar reaction to Experiment #2. This experiment has demonstrated that an anchorage bend can be constructed and seated that translates most of its force to the anterior segment. This entire series of experiments has convinced the authors there is more to an anchorage bend than an angle bent into an archwire, someplace mesial to the molar sheath. The lessons learned from these typodont experiments were translated into clinical experiences. The anchorage bend should be designed and fashioned so it has the least effect upon the molar and maximum intrusive action on the incisors. Buccal Tube Placement An in-depth and critical analysis of intraoral slides and models of patients treated in earlier years indicates that the positions in which the buccal sheaths were placed may have been responsible for not attaining significant intrusion of incisors. Placing the buccal tubes parallel to the occlusal surface of the molar may be an error Threading an archwire through sheaths that are parallel to the occlusal surface reveals that a definite anchor bend b required, just to have the wire lie passively in the anterior brackets (Fig. 10A). Such an anchor bend is apt to slip forward without exerting sufficient intrusive force. Even the slightest distal tipping of the molar will only make the situation worse. All the action of the anchor bend will be required to keep the wire passive in the canine brackets, leaving very little, if any, intrusive force (Fig. 10B,C). In order to accomplish the intrusive tooth movements on the maxillary incisors, some modifications in Begg mechanotherapy are suggested. The buccal sheaths on the molar bands and the attachments for elastics are placed in a specialized manner (Fig. 11). The buccal tubes may be round or oval, in accordance with the operator's preference.

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The mandibular sheath should be located close to the gingival margin. The anterior border is just slightly mesial to the crest of the mesiobuccal cusp. Such positioning will lessen the tendency of a Class II elastic to cause a mesial rotation on the molar. The buccal sheath may be shimmed to whatever degree prescribed. The attachment for the elastic is soldered over the distal portion of the sheath. It is placed occlusal to the tube and bent occluso-gingivally, so there is a slight space between the hook and the sheath (Fig. 12). The maxillary tube is done differently. It is tack-welded with the mesial edge just forward of the center of the mesiobuccal cusp. A wire is passed through the tube and the tube is angulated so that the wire rests at the gingival border of the bicuspid (Fig. 10D). Shimming may be included as desired. The elastic attachment is soldered on the distal edge and occlusal border of the sheath. It is bent gingivally, with a little room left between the hook and the tube. When this arrangement is used on a maxillary molar, the difference with the earlier type of sheath placement is apparent. The activation on the anchorage bends can be lessened, but there will be a more effective intrusive action on the incisors (Fig. 10E,F). In classic treatment the test of proper anchorage bends is to seat the archwire into both tubes, and the anterior portion of the wire should rise to the mucobuccal fold (Fig. 10B). The same is used with the modified angulated tubes (Fig. 10E). It is recommended that a few millimeters of wire be left extending distally beyond the sheaths, and these should be left straight, not turned in. Modified Mechanotherapy Bonds or bands are secured to the maxillary and mandibular incisors. The mandibular second bicuspids may or may not be banded (or bonded). The maxillary second bicuspids are specifically left without any bracket attachments. When initial archwires are prescribed, the decision for loop construction should be modified. The use of loops is minimized. Plain wires are considered more efficient. However, if loops are deemed essential they may be utilized. When the incisors are moderately irregular, it is possible to correct these malpositions without loops. Simply tying the irregular teeth to the archwire with steel ligatures is effective. As already explained, the placement of the anchorage bends is important and critical. In the mandible these are located midway between the distal of the second bicuspid brackets and the mesial of the buccal tubes, the same as in classic Begg mechanotherapy. In the maxilla, the anchor bends are placed closer to the buccal sheaths (Fig. 13). The suggested procedure is to seat both the maxillary and mandibular archwires at the same appointment. The patient is then instructed to wear vertical elastics from the buccal attachment on the upper molar to the buccal attachment on the lower molar band. The elastic most used is Unitek 1/8". These are to be worn all the time. The patient is then dismissed for four weeks. Servicing the patient carefully is as important now as in other methodologies: 1. Look for loose bands or bonds. 2. Note if ties or pins are secure. 3. Determine there are no broken or distorted archwires. 4. Note if the patient is wearing the elastics in exact accordance with instructions . 5. See if there is a changing relationship of the incisors, that the deep anterior overbite is being relieved as the maxillary incisors intrude. 6. Check for mobility of molars. Our experience has been these anchor teeth remain remarkably stable and exhibit little if any mobility. 52

As the anterior bite relationship improves, it may be prudent to keep the momentum going, by removing the existing archwire and perhaps increase the activation on the anchorage bends. Frequently the bite opens in the cuspid areas first. When it has opened 2 - 3 millimeters, it is then suggested that the four incisors be pinned and the cuspids tied lightly with steel ligatures, which will allow the centrals and laterals to "catch up". The operator should be conscious of the "whip" potential within the curvature of the archwire (Fig. 14A). If, at the beginning of treatment the incisors and cuspids are at the same level, the incisors may extrude in relation to the canines. In these instances, and where the canines do not require much intrusion in order to glide into Class I positioning, the incisors are pinned and the cuspids tied lightly (Fig. 14B) thereby transferring the intrusive force to the centrals and laterals, with dramatic depressive tooth movements. If the maxillary incisors are protrusive and require retraction, very light Class II elastics are prescribed. The authors suggest Unitek #404-156, 3/8" and #404-166,5/8". These must exert only a slight pull. Otherwise they negate the effect of the vertical elastics. The objective is still essentially intrusion. In Class II division 2 malocclusions, where the maxillary incisors are usually vertical, Class II elastic traction is contraindicated at least until the bite has opened by significant intrusion of the maxillary anterior segment. In these malocclusions, the response is particularly gratifying. The bite opens, the axial inclinations of the maxillary incisors improve rapidly as the roots intrude and the crowns come forward slightly. The recommendation is to allow a great amount of intrusion to occur before proceeding to later phases of treatment. The clinician who follows these suggested procedures with care and diligence will learn that the technique is uncomplicated and the results gratifying. This technique will now be documented with actual cases in treatment. At the Orthodontic Department of the University of Groningen, two groups of cases were started for comparison purposes. One group was placed under treatment with classic Begg mechanotherapy. The other group was treated with Begg appliances with the modifications described in this paper. This latter group was also studied closely as to sizes and shapes of the alveolar processes and the palatal cortical plate. The authors recognize that there are limitations in making comparisons of this nature. However, they should clarify the objectives. CASE REPORTS Case W.J. This was a Class II division 1 malocclusion (Fig. 15) treated nonextraction with classic Begg mechanotherapy. At the start of Stage III (Fig. 16), the superimposition of the cephalograms indicates there was backward rotation of the mandible, concomitant with an opening of the Y axis. The occlusal cant tipped downward 6°, from 21° to 27°. This was due to the 3 millimeter extrusion of the mandibular molars and a 2 millimeter intrusion of the mandibular incisors. It must be noted that there was a relative extrusion of the maxillary incisors. Although the incisal edges of the maxillary anteriors remained at the same distance from the palatal plane, the incisors were actually extruded 2.5 millimeters in relation to the occlusal plane. There was also an increase in the palatal plane/maxillary occlusal plane angle from 18° to 22°. Note the unfavorable relation of the incisor root apex as it came into juxtaposition to the lingual cortical plate. In order to achieve a proper esthetic result, significant lingual root torquing will be required. Shortly after Stage III mechanics were applied, it can be seen in the x-ray that the crown was beginning to come forward along with a further extrusion of these teeth. Case H.H. A Class II division 1 (Fig. 17) treated nonextraction, with the suggested modifications in mechanotherapy. For the first three months of active therapy, Class II elastics were deliberately omitted. During this period, the objective was to permit the intrusive forces to direct the root apices of the anterior teeth upward and distally well into the alveolar housing, prior 53

to any tipping movements. During this phase, only vertical elastics were worn. Afterwards, very light Class II elastics were added. At the start of Stage III (Fig. 18), the cephalometric superimposition reveals the maintenance of the relation of the different planes to each other. Pogonion moved forward and the mandible dropped down straight. There was no untoward rotation. No special effort was made to intrude the mandibular incisors, yet they were depressed 2 millimeters. The mandibular molar did not elevate, and there was slight mesial root movement. The response of the maxillary incisors was favorable. These were retracted, along with a significant amount of intrusion. The incisal tip was repositioned upward 2 millimeters in relation to the original maxillary occlusal plane. The palatal plane/maxillary occlusal plane angle was decreased from 9° to 7°. The upper molar was not extruded, but did have a slight displacement of its roots mesially. Of extreme importance was the relation of the root apices to the palatal cortical plate. These are well forward to the anatomical barrier. The torque requirements have been lessened by the substantial intrusion obtained. Any necessary lingual root repositioning of the apices should not be a difficult task, since there will be ample room within the cancellous bone to attain a favorable axial inclination. Case A.W. Another Class II division 1 malocclusion (Fig. 19) treated using classic Begg mechanics, with the removal of the four first bicuspids. It took eight months to reach Stage II (Fig. 20). Cephalometric changes show the Y axis has opened and there has been a backward rotation of the mandible. On the lower arch, the molars extruded 3 millimeters, but the incisors tipped labially without intruding. In the maxilla, the incisal edges remained at the same distance from the palatal plane, but were extruded 1.5 millimeters in relation to the original maxillary occlusal plane, and the apices came forward. The extrusion of the incisors relative to the alveolar process and their lingual axial inclination made it necessary to accomplish massive torque movements. Fortunately, in this patient, the curve of the palatal cortex extends posteriorly far enough, so if there is no further lingualization or extrusion of the anteriors, attainment of reasonable axial inclination of these teeth is anticipated. Case P.K. A Class II division 1 problem (Fig. 21) treated with the extraction of the maxillary first bicuspids and mandibular second bicuspids, and Begg mechanics with recommended modifications. Since the maxillary incisors were very protrusive, treatment was initiated with vertical and light Class II elastics. After eight months of therapy, Stage II was reached (Fig. 22). The cephalometric superimposition shows a well controlled Y axis and mandibular plane angulation. In the mandible, the molars extruded 1 millimeter and maintained their axial posture. There had been no effort made to intrude these teeth. The changes in the maxillary arch were particularly gratifying. Even with the reduction of the protrusion, the incisal edges moved up 1 millimeter from the original occlusal plane. This case emphasizes that a great deal of intrusion is required to properly control the incisal edges in the vertical plane while performing retraction. Torque requirements will be minimal and should present very few problems, because of the favorable position of the root apices to the palatal cortex, as seen in the x-ray. (The next three case reports are from the practice of Sidney Brandt, DDS, Morristown, N.J. The tracings for these cases were done by Dr. Joel Servoss, Department of Orthodontics, New Jersey College of Dentistry.)

Case M.C. 54

A Class II division 1 crowded malocclusion. The four first bicuspids were removed and treatment begun with Begg appliances, with modifications. After approximately five months of active therapy, with only vertical elastics prescribed, satisfactory bite opening was noted (Fig. 23). The Y axis and mandibular plane angle remained relatively constant. There was no backward rotation of the mandible. In the lower dentition, the molar was extruded 1.5 millimeters and slid forward 2 millimeters. The incisor remained at the same level and lingualized slightly. In the maxilla, the anterior segment intruded 2.5 millimeters as measured from the original maxillary occlusal plane. The molar slipped mesially slightly and remained at the same level. ,There was a decrease of 4° in the maxillary occlusal plane/palatal plane angle. Case M.M. This was a Class I protrusive case. The first bicuspids were extracted and Begg appliances with modifications were prescribed. After three months of appliance therapy that restricted elastic wearing to vertical pull, a cephalometric superimposition (Fig. 24) showed that the Y axis and mandibular plane angle remained as in the original malocclusion. In the mandible, there was slight extrusion of the molar, but the incisors remained relatively unmoved. In the maxilla, the molar was unchanged and the anterior segment was intruded 2 millimeters to the original maxillary occlusal plane. There was a decrease of 2° in the maxillary occlusal plane/palatal plane angle. Excellent bite opening was achieved. Case T.P. Another Class II division 1 case. The first bicuspids were extracted and Begg appliances, with modifications, were applied. After approximately three and one-half months of treatment with vertical elastics only, a serial cephalometric radiograph was taken. Its superimposition (Fig. 25) showed a stable Y axis and a relatively unchanged mandibular plane angle. In the lower arch, both the molars and incisors appeared essentially the same. In the maxilla, the molar crown tipped mesially slightly and the incisor intruded 2 millimeters. The maxillary occlusal plane/palatal plane angle reduced 1.5°. The purpose in displaying these cases is to explain the need and ease in intruding maxillary incisors. It is not enough to keep them at the same distance from the palatal plane. Active intrusion is required to keep the incisal level on, or preferably above, the original occlusal plane. Lack of anterior intrusion does not always result in torquing problems. Nor does excessive intrusion guarantee excellent results. The size, shape, and width of the maxillary alveolar process may determine the extent and the limitations of possible tooth movement. These points are illustrated in the following case report. Case M.G. The case was originally a bimaxillary protrusion (Fig. 26). The tracing displays an elongated hyperplastic maxillary alveolar process, which gives the patient characteristic features. It should be evident that there is very little room within the alveolar housing to perform the necessary tooth movements to correct the skeletal deficiencies. If the incisors were lingualized, with the fulcrum at the apices, in all probability there would be extrusion, and tooth movement in the marginal area would result, which could only be unfavorable. If retraction with bodily movement were attempted, the roots would be in contact with the dense cortical plate, which is also not good. The ideal objective would be to accomplish a great amount of intrusion, which would bring the apices into a larger area where root movements can be performed with greater confidence. In this malocclusion, vertical and light Class II elastics were prescribed simultaneously. The objective was to guide the anterior segment upward. After eight months, tremendous changes were effected in the patient's profile (Fig. 27). Retraction and intrusion were both accomplished. The incisal edges moved upward 2.5 millimeters from the original maxillary occlusal plane. The molars were not extruded, and only slightly tipped. 55

At this point in treatment, there still remained a few millimeters of overjet. R was tempting to reduce this by prescribing stronger elastics. This was resisted, because it was feared that the incisors might be brought into unfavorable relation to the dense cortical bone, despite all the intrusion already achieved. The x-ray shows that the cortical plate at this point is half-way up the root. Treatment will be continued to keep intruding the anteriors, along with mild tipping. It is hoped that this will further reduce the overjet, keep the incisal level stable and the conical plate will be relatively closer to the incisal edges. The torquing requirements are anticipated as minimal and should be accomplished away from the dense cortical plate. When the incisors are in their final positions, a great deal of the conical plate will have to be remodeled. There are malocclusions that present teeth in juxtaposition to the lingual conical plate, or that will assume that relationship as soon as Class II elastics are applied. Typical of these problems are Class II division 2 cases, and those resembling these malocclusions. In these instances, Class II elastics will lingualize the anterior crowns further and move the apices forward so they will contact the labial plate. In these malocclusions, the authors specifically discourage immediate application of Class II elastics. Vertical elastics, along with properly fashioned and placed anchor bends, are recommended. The anterior crowns then move forward as the roots intrude lingually. Thus, a far better position within the alveolar process is attained. The superimposition in Figure 28 demonstrates what happened in six months. The incisal level moved upward 5 millimeters from the original occlusal plane. The molars tipped distally slightly, and did not extrude. At this point light Class II elastics were added to help guide the incisors as they intruded. Similar treatment procedures are followed in Class II division 1 cases where the maxillary incisors are in a straight, prognathic position, with their apices close to the labial plate. If intrusive and tipping movements are initiated simultaneously, there is some danger of these apices striking the labial bone. It is therefore recommended that the anteriors be intruded prior to prescribing Class II traction (Fig. 29). Summary In the first article18 of this series, it was stressed that lingualization and extrusion of maxillary incisors may bring them into close relation to the dense lingual cortical plate. Such positioning makes proper lingual root torque a questionable and perhaps impossible procedure. In this paper, a technique was outlined that makes it possible to avoid such unfavorable conditions. Documentation with several cases was supplied and discussed. In the cases shown that were in actual treatment, the author's objective was to emphasize the need for intensive intrusion of the maxillary incisors. This could be accompanied by slight lingual tipping, but the major effort should be intrusive. When Class II elastics are added, only those with very light pull should be prescribed. The typodont experiments were devised and reported to stress the potentials within the anchorage bends. These tests demonstrated how it is possible to stabilize the molars so that vertical anchorage could be attained, and an intrusive force can be transmitted to the anterior segments. This could be done just as easily to the maxillary incisors as to the mandibular anteriors. The vertical elastics, attached to the hooks over the distal ends of the tubes seem to add capabilities in this aspect of treatment. Note the amount of intrusive movement accomplished on the maxillary incisors using the system described. It suggests bodily movement can be controlled with round wires. The angulated buccal sheaths on the maxillary molar bands are an integral part of this method, and require understanding in order that proper positioning be obtained. What this investigation has revealed pertains to all fixed appliance systems, and in no way has indicted any system or technique. The reader can prove this to himself by perusing the literature, in published articles and textbooks, and note the illustrations of cephalometric x-rays of completed cases. Invariably, the root apices, maxillary and mandibular, are close to or at the anatomical barriers discussed in our papers, regardless of the appliance system used. Thoughtful orthodontists are urged to study the cephalometrics of their own finished cases and see where the incisor root apices were positioned. This study transcends technique. 56

ACKNOWLEDGEMENT — The authors wish to thank the following people for their generous assistance in the preparation of this paper: Dr. Kees Booy, Els-Marjan Groenman, Department of Orthodontics, University of Groningen. R.L. Dijkstra, P. Hartevelt, K.J. Pel, Photography Department, University of Groningen . Mr. van der Pol, Institute of Instrument Fabrication, University of Groningen. Dr. Joel Servoss, Department of Orthodontics, New Jersey College of Dentistry. Mr. Josh Johnson, Photography Department, New Jersey College of Dentistry. (In the next and final paper of this series, attention will be directed to the mandibular dentition.)

Ref Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Mar(174 - 198): Technique Modifications to Achieve Intrusion of the Maxillary Anterior Segment. -------------------------------1. Lefkowitz, W. and Waugh, L.: Experimental Depression of Teeth, Am. J. Ortho. & Oral Surg. 31:21-36, 1945. 2. McDowell, C.S.: The Hidden Force, Angle Ortho. 37:109-131, 1967. 3. Dellinger, E.L.: A histological and cephalometric investigation of premolar intrusion in the Macaca Speciosa monkey A.J.O. 53:325-355, 1967. 4. Stenvik, A. and Mjor, I.A.: Pulp and dentin reactions to experimental tooth intrusion A.J.O. 57:370-385, 1970. 5. Reitan, K.: Initial Tissue Behavior During Apical Root Resorption, Angle Ortho. 44:68-82, 1974. 6. Magill, J.M.: Changes in the Anterior Overbite Relationship Following Orthodontic Treatment in Extraction Cases, A.J.O. 46:755-788, 1960. 7. Poulton, D.R.: A three-year survey of Class II malocclusions with and without headgear therapy, Angle Ortho. 34:181193, 1964. 8. Merrifield, L.L. and Cross, J.J.: Directional Forces, A.J.O. 57:435-464, 1970. 9. Barton, J.J.: A cephalometric comparison of cases treated with Edgewise and Begg Techniques, Angle Ortho. 43:119126, 1973. 10. Barton, K.A.: Overbite Changes in the Begg and Edgewise Techniques, A.J.O. 62:48-55, 1973. 11. Williams, R.: Begg Treatment of High Angle Cases, A.J.O. 57:573-589, 1970. 12. Cadmun, G.R.: A vademecum for the Begg technique: technical principles, A.J.O. 67:477-512, 1975. 13. Bijlstra, R.J.: Vertical changes during Begg treatment, Transactions European Ortho. Soc., 1969.

57

14. Levin, R.J.: Begg orthodontic therapy in retrospect, Mastsr's thesis, Orthodontic Department, University of Groningen, 1975. 15. Sims, M.A.: Reciprocal Orthodontic Phenomena, Australian Ortho. J., June 1968. 16. Swain, B.F.: Begg Differential Light Force Technic, Current Orthodontic Concept and Techniques (Graber) VoL 2, W.B. Saunders Co., Philadelphia, 1975. 17. Edwards, J.G.: A study of the anterior portion of the palate as it relates to orthodontic therapy, A.J.O. 69:249-273, 1976. 18. Ten Hoeve, A. and Mulie, R.M.: The effect of antero-postero incisor repositioning on the palata cortex, as studied with laminagraphy, J. Clin. Ortho. 10:804-822, 1976.

Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1969 Apr(176 - 195): Treatment of High Angle Cases With the Begg Technique - GEORGE V. NEWMAN, D --------------------------------

BEGG SERIES PART VIII Treatment of High Angle Cases with the Begg Technique GEORGE V. NEWMAN, DDS 58

It is through the persevering clinical research of such outstanding contributors to the orthodontic profession as Tweed1, Schudy2, Bjork3, Ricketts4, and others5,6 that we owe our insight into the analysis and treatment of high and low angle cases. To facilitate communication between the author and the reader, a few definitions are in order. Patients exhibiting a hyperdivergent, clockwise growth pattern and whose FM Angle is between 35°-50° may be defined as high angle cases. Low angle cases have an FM Angle range from 10°-25°. The low angle cases usually have a counterclockwise hypodivergent, vectorial growth pattern. As a general rule, patients exhibiting vertical growth patterns have higher FM Angles than those whose growth is predominantly in a horizontal direction. Low angle cases The low angle patients usually have a more favorable growth pattern and a larger chin process than the high angle cases. In fact, the chances of improving the facial profile are better in low than high angle cases. The twenty degree FM Angle facial profile will usually be straight with a definite chin, while the thirty-five degree FM Angle face will be more convex and have a less prominent chin. Furthermore, growth will be predominantly horizontal in the low FMA cases, while in the high angle cases growth will be predominantly vertical and may show unfavorable growth characteristics. Low angle cases present little problem with the Begg technique7 and for that matter with most techniques, since good downward and/or forward growth coupled with proper treatment usually results in successful treatment. Class II elastics tend to elevate the lower posterior alveolar segment which influences bite opening and stimulates downward and forward growth in low angle cases. Low angle cases are a functional, muscular problem, while high angle cases are commonly skeletal in nature. Since most of our treatment problems are associated with treatment of high angle cases, I shall confine my clinical observations hereafter to treatment of high angle cases with the Begg technique8. Observations on high angle cases Several of the overall general observations that I have noted from studying a clinical sampling of high angle cases from my practice are as follows: • When employing Class II elastics in the Begg technique in Class II and Class I bimaxillary protrusion high angle cases there is usually some extrusion of the upper incisors and tipping of the cant of the occlusal plane. As a result, at the end of Stage I the FM Angle tends to increase, since Class II elastics elevate the lower molars and thereby tend to thrust point B and pogonion vertically and/or distally. On the other hand, during Stage II the lower molars are brought forward into a wider intra-alveolar width tending to usually decrease the FM Angle. • During Stage III the uprighting springs and torquing arch influence the depression of the upper molars thereby diminishing the vertical displacement of the mandible due to upper first molar extrusion. However, if a great deal of anterior lingual torque or torquing time is necessary to obtain proper axial inclination of the upper incisors, prolonged and excessive Class II elastic force is necessary. This additional elastic force may result in raising the posterior mandibular alveolar segment, tipping the occlusal plane, and finally causing downward and backward mandibular rotation. In severe high angle cases (FMA 40°-50 ° ) this can be a problem. • I have found it clinically advisable during Stage III to use an .020 or .025 inch base archwire instead of an .016 inch archwire in order to decrease buccal tipping of the upper first molars. If buccal tipping occurs, the mesio-lingual cusps of the upper first molars may supraocclude upon the disto-buccal cusps of the lower first molars opening the intraocclusal width which also tends to thrust the chin downward and backward. • Post-treatment cephalometric radiograms of treated high angle cases reveal that where total vertical growth (growth at nasion, of the body of the maxilla, maxillary posterior and mandibular alveolar processes) exceeds condylar growth, 59

the mandible may continue to grow vertically and/or vertically and posteriorly. When vertical growth is equal to condylar growth, the mandibular plane may revert back to almost its original cant subsequent to treatment. Fortunately in males, condylar growth occurs until 19 to 21 years of age. • An analysis of my Begg-treated high angle cases reveals three types of post-treatment growth response: (1) downward, (2) downward and forward, and (3) downward and backward. Briefly, post-treatment growth is variable, but usually having a vertical growth pattern. Vertical growth, advantageously tends to reduce the overbite. • A comparison of Begg-treated high angle cases with edgewise-treated cases indicates similar mandibular responses. The morphogenetic pattern of the individual treated will be expressed eventually, whatever technique is employed. The basic facial growth pattern is independent of treatment and improvement of occlusal relations. Patients having an FM Angle over 35° usually have large anterior facial heights in contrast to short posterior facial heights. Where ramal growth is not forthcoming, orthodontic treatment is limited whatever appliance is utilized. Nevertheless, every attempt should be made to prevent the extrusion of the upper and lower molars. One should be wary of extruding the upper and lower molars where a cephalometric analysis reveals that the FM Angle exceeds 35°, the Y Axis is larger than 65°, there is an ANB difference over 6°, there is little chin process, and the Mandibular Facial Depth Angle (MFDA) is over 77° (Figure 1). This suggested cephalometric analysis should be used only as a tentative guide. Facial growth and its coordinated components are noted for their individual infinite variations; however, high angle cases do have a recognizable pattern. • In adults, where growth is complete, the FM Angle opens slightly during and after treatment. However, during the post-treatment period it may revert back to its original FM Angle, or less, and so does the occlusal plane. • In cases where the patient has a Class II molar relationship, one cusp width, and the FM Angle exceeds 40°, the Y Axis is larger than 65°, the MFDA exceeds 77°, there is a large ANB difference (7°-12° ) and there is no lower arch length discrepancy, I have removed upper bicuspids only. The upper anteriors were retracted with horizontal elastics. The lower anteriors were not moved lingually and Class II elastics were not used. Nevertheless, the mandible, in severe high angle cases (40°-50°) occasionally moved down and back. Other factors There are other variable factors that should be considered in treating high angle cases besides genetic pattern which are not within the scope of this article, and they are: (1) neck and facial musculature and (2) postural tongue position and tongue-thrusting. • When vertical growth exceeds condylar growth, the former is dominant. Orthodontic appliances (e.g. extraoral force), as far as I am aware of, clinically affect the maxillary posterior alveolar process and can temporarily inhibit posterior alveolar vertical growth. However, this force is not too effective against growth at nasion and the maxillary bone. When this extraoral force is discontinued, then post-treatment the morphogenetic growth pattern will again express itself, no matter what orthodontic method was employed. Three high angle cases One can learn a great deal by clinical examination of treated cases, therefore let us examine three high angle cases. In two of these cases extraoral force was used as an adjunct9. It was used because of loss of anchorage due to excessive elastic force, torque, tip backs, and lack of patient cooperation, resulting in vertical and posterior movement of the mandible. I would like to point out that I do not use extraoral force routinely in high angle cases with the Begg technique. However, where a progress cephalogram reveals unfavorable growth characteristics and treatment response, then extraoral force 60

is a helpful adjunct. To be succinct, extra oral force is used to support anchorage in severe high angle cases. Distal driving is contraindicated. In all three cases reported, light .016 inch wires, light differential elastic force, and light wire brackets were employed. CASE 1 Patient K.H. was a twelve-year-old girl manifesting a Class II Division 1 malocclusion (Figure 2). There was a nine millimeter overjet and a severe anterior tongue thrust habit (Figure 3). She was one of my first Begg bicuspid extraction cases. Subsequently, Australian light wire brackets were used. Since the FM Angle =38°, Y Axis=71°, ANB=10° and the MFD Angle = 78°, I would classify this patient as a high angle case. The body of the mandible and ramus were short and there was a vertical vectorial growth pattern (Table I). At the end of Stage I, much to my consternation, a progress cephalogram revealed that the FM Angle had opened to 44°, the Y Axis was 74°, and the lower incisors were tipped to an unfavorable 107° . The upper and lower molars were being extruded. A cephalometric analysis indicated that point B and pogonion were moving down and back. Anchorage was being lost. Fortunately, at the end of Stage II, a cephalometric analysis revealed an improvement due to use of horizontal and Class III elastics. However, when Class II elastics were used during Stage III with the auxiliary torquing arch, the lower incisors tipped labially and the mandible rotated down and back again. As a result, an .020 inch base archwire with soldered hooks between the central and lateral incisors was inserted. Uprighting springs and the auxiliary torquing arch were also placed at this time10. A high pull headgear (Lee type) was worn 12-14 hours per day (attached to the soldered hooks), while 2-ounce Class III elastics from the lower archwire hooks were worn to the ends of the upper archwire. The before and after cephalometric tracing (Figure 4) showed the following improvement: the FM Angle decreased to 36°, the Y Axis was reduced to 66°, and the upper incisors were torqued to 100°. A maxillary superimposition (Figure 5) indicated that the upper first molars and upper incisors were intruded; a mandibular superimposition revealed that the lower first molars were slightly elevated and came forward while the lower incisors were depressed. Correction of treatment errors lead, many times, to supportive treatment methods. Hawley-type bite plates were used as retainers (Figure 6). The out-of-retention cephalometric radiogram (five years) superimposition (Figure 7) indicates the morphogenetic growth response continues to be vertical. Overbite correction, accordingly, is stable. The occlusal-mandibular plane has been reduced from a before 24° to a flatter out-of-retention 17°. This case is an example of how the Begg appliance is so sufficiently versatile that one can adapt auxiliary methods to obtain a satisfactory treatment goal. Goals such as maintaining the integrity of the occlusal plane as well as working within the morphogenetic growth framework of the individual have been accomplished, although an unfavorable growth response has occurred during treatment (Figure 7). CASE 2 Patient C.B. was a twenty-three-year-old young woman exhibiting a Class II Division 1 malocclusion (Figure 8). Upper and lower first premolars were removed. A cephalometric analysis indicated a minimal chin process, 1 to NB=9, NB to PO=0 (Figure 9). It is interesting to note that prior to treatment (Table II) the FM Angle was 42°, at the end of Stage II it decreased to 39°, and at the end of Stage III it increased to 44° . Finally, three years out of retention the FM Angle decreased to 38°. Tracings before and after treatment superimposed on sella indicate that there has been no growth of the corpus of the maxilla and that backward rotation of the mandible has occurred. A maxillary superimposition reveals that the upper incisors were moved bodily distally and extruded while the upper molars were tipped distally and slightly extruded. A 61

mandibular superimposition reveals that the lower molars were elevated and moved forward while the lower incisors were depressed. Evidently, backward rotation of the mandible was caused primarily by elevation of the lower molars and slight extrusion of the upper molars (Figure 10). The after and out-of-retention cephalograms indicate that the mandible has moved back to its original position (Figure 11). It is interesting to note that the occlusal-mandibular plane (24°) has returned to relatively the same angular measurement prior to treatment (25°). The depressed lower incisors have extruded and the bite is tending to close (Figure 8). The extraoral photos demonstrate a dramatic facial improvement in the oro-facial area. The strained lips and hypertrophied mentalis musculature have been corrected by the retraction of the anterior teeth (Figure 12). CASE 3 Patient M. W. was a nine-year-old girl evidencing a severe overjet of nine millimeters and a moderate lower arch length discrepancy. She displayed tongue thrust and thumbsucking habits which were apparently broken with a removable appliance prior to starting treatment. M.W. was treated as, what I term, a mixed dentition, first premolar "serial" extraction Begg case (Figure 13). Her FM Angle of 35°, Y Axis = 65°, ANB = 8°, and MFD Angles = 80°, indicated a vertical growth pattern tendency (Table III). When it was noted (progress cephalogram) during Stage III that the upper molars had extruded, the lower incisors tipped too far labially, and the mandible was moving down and back, high pull extraoral force and Class III elastics were resorted to for three months in order to correct this unfavorable vertical dysplasia. A Lee-type high pull headgear was used with a face bow that inserted into an .050 inch tube that had been soldered occlusally to the .036 inch tube. The outer arms of the face bow ended in the first molar area. The extraoral force was sufficient to cause intrusion of the upper first molars and to withstand the two-ounce Class III elastic force from the lower archwire. (Distal movement of the upper molars is to be avoided under these circumstances. Under no conditions should cervical anchorage be used in a high angle case.) A before and after treatment growth superimposition illustrates that growth was predictably in a vertical direction (Figure 14). The maxillary superimposition indicates that the lower molars elevated slightly and came forward while the lower incisors were slightly extruded due to the use of Class III elastics (Figure 15). The after and out-of-retention cephalograms (Figure 16) indicated that the vector of growth has become predominantly vertical. There is some horizontal growth as well, which is a favorable posttreatment adjustment. The FM Angle has returned to its original 35°, although the Y Axis has increased from 65° to, out-of-retention 67° . Fortunately, the MFDA has decreased from 80° to 77°, indicating that the gonial angle is becoming less obtuse. Although the occlusal plane flattened after treatment (16°), it returned to its original cant (19°) during the posttreatment growth phase. M.W. has been growing into a tall, thin young lady. Her posttreatment facial photographs (Figure 17) portray additional nose growth. This facial feature is in the realm of genetics and rhinoplasty. It is not within the control of orthodontic treatment. Notice the increased anterior facial height. Summary Class II elastic force is a necessity in the Begg technique to open the bite. This facilitates tooth movement by minimizing cuspal interference in high angle Class I and Class II bimaxillary protrusion cases. This method of bite opening enhances anchorage and decreases treatment time. Additionally, the mandibular molars are usually moved occlusally resulting in an adequate increase in anterior dental height overbite correction which is nearly always maintained in the post62

treatment growth period. Paradoxically, in severe high angle cases movement of molars occlusally can result in treatment problems. In those severe high angle cases where cephalometric analysis indicates a tendency for the mandible to move down and back before and during treatment, it is advisable to use minimal Class II elastic force, minimal tip-backs, and occasionally use high pull extraoral force with the versatile Begg technique. One may argue that extraoral force is usually not necessary when treating high angle cases with the Begg technique, and I shall agree. On the other hand, where there is a high FM angle (35°-50°), large Y Axis, large ANB difference, severe lower arch length discrepancy, MFD Angle over 77°, where patient cooperation in elastic wearing is poor, and where it is noted that the mandible is moving down and back, it may be necessary to employ adjuncts such as extraoral force. Most of us who have used the Begg technique from its early introduction realize only too well that "Pure Begg" has been modified by many of its advocates.

Ref Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1969 Apr(176 - 195): Treatment of High Angle Cases With the Begg Technique - GEORGE V. NEWMAN, D. -------------------------------1. Tweed, C. H.: Clinical Orthodontics, St. Louis, 1966. C. V. Mosby Company, Vols. I and 2 2. Schudy, F. F.: The Association of Anatomical Entities As Applied to Clinical Orthodontics, Angle Orthodontist 36: 190203, 1966 3. Bjork, A.: The Face in Profiles, Berlingske Bok, Tryckeriet, Lund, 1947 4. Ricketts, R. M.: The Influence of Orthodontic Treatment on Facial Growth and Development Angle Orthodontist 30: 125, 1960 5. Brodie, A. G.: On the Growth Pattern of the Human Head, From the Third Month to the Eighth Year of Life, Am. J. Anat. 68: 209-262, 1941 6. Holdaway, R.: Changes in Relationships of Points A and B During Orthodontic Treatment, Am. J. Orthodontics 42: 176193, 1956 7. Begg, P. R.: Differential Force in Orthodontic Treatment, Am. J. Orthodontics 42: 481-510, 1956 8. Begg, P. R.: Light Arch Wire Technique, Am. J. Orthodontics 47: 30-48, 1961 9. Newman, O. V.: A Biomechanical Analysis of the Begg Light Arch Wire Technique, Am. J. Orthodontics 49: 737, 1963 10. Barrer, H. G.: A Survey of Begg Treatment, Am. J. Orthodontics 49: 494-506, 1963

Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1976 Nov(804 - 822): The Effect of Antero-Postero Incisor Repositioning on the Palatal Cortex as Studied with Laminagraphy -------------------------------63

The Effect of Antero-Postero Incisor Repositioning on the Palatal Cortex as studied with laminagraphy DR. ANE TEN HOEVE DR. ROBERT M. MULIE This is the first of a series of three papers. It is restricted to findings within the maxillary arch. The paper to be published next month will be confined to a study of the mandibular dentition. These two papers were presented before the European Begg Society in Timmerdorfer Strand, Germany in May 1976. Your editor has rewritten these papers for publication here. the near future, a joint paper by Drs. Ten Hoeve, Mulie and myself, describing recommended modifications in mechanotherapy, will be published in the Journal of Clinical Orthodontics. SIDNEY BRANDT, DDS, Associate Editor

Many orthodontists have accepted the "pressure/tension" theory as an explanation of the biological mechanism of orthodontic tooth movement. Sandstedt is credited with initiating this belief with his observation in 1904 of "undermining resorption". Over the years, the pressure/tension theory underwent modification, influenced by extensive research.1 As an example, DeAngelis2 wrote that mechanotherapy causes a bending of the alveolar process, resulting in piezoelectric changes, which evolve a cellular response throughout the alveolar process. It is evident that orthodontic tooth movement takes place within the alveolar process. With constantly increasing sophistication in fixed appliance mechanotherapy, techniques have evolved which, in theory, make it possible for the orthodontist to effect tooth movement in any direction and to any extent desired. Such versatility has resulted in several commonly accepted treatment objectives, among which are: 1. an edge-to-edge incisal relationship, 2. elimination of the curve of Spee, and 3. a favorable interincisal angle. There are many cephalometric analyses suggesting a positioning of the incisors in relation to anatomical landmarks. Limits of Cephalometric Evaluation Recently, some investigators have warned that orthodontists should not overemphasize cephalometric evaluation at the expense of understanding that anatomy would place limitations upon tooth movements in certain specialized instances. Duterloo5 observed a definite shortening of the marginal aspect of the palatal cortex following orthodontic treatment. There did not seem to be any repair or remodeling, even several years after treatment. This elicits a natural question— When does orthodontic treatment cause a loss of alveolar bone to the extent that irreversible damage results? Edwards6 has also questioned the limitations of tooth movements based upon his studies of the anterior portion of the palate. These observations of Duterloo and Edwards were verified by the authors on cephalograms of their treated cases, demonstrating the aspect of the palatal cortex visible on cephalometric headplates (Fig. 1). However, since cephalometric headplates are midsagittal projections of several structures, there is no certainty of obtaining from them a perfectly clear 64

x-ray view of the bony structures palatal to the maxillary incisors. In an effort to clarify this anatomical area, the authors utilized laminagraphy. Use of Laminagraphy The laminagraph used at the Institute of Radiology at the University Hospital, Groningen, Holland is a Philips Horizontal Polytoom XD 4005-SPX 68 8E (Fig. 2). This machine makes a hypocycloidal motion. The midsagittal plane of the patient's face is positioned parallel to the table on which the patient is lying. The distance from the table to the long axis of one of the maxillary central incisors is measured and the sagittal plane of this incisor is adjusted to the x-ray beam by moving the table up or down. When the post-treatment cephalogram of the patient in Figure 1 was compared to his laminagram (Fig. 3), the laminagram demonstrated newly formed cortex all the way to the cemento-enamel junction and indicated that a significant amount of remodeling of the palatal cortex occurred after extensive bodily movement. Two possible reasons why the palatal cortex is visible on a laminagram and not on a cephalometric x-ray are: 1. With laminagraphy, only a thin area is x-rayed and there is no overlapping of the various structures which occurs on a cephalogram. 2. The laminagram is exposed with 45KV, compared to 90KV for cephalograms. The higher KV level may "burn" out the thinner palatal structures. The importance of the KV level can be demonstrated with two laminagrams of the same patient taken at two different KV levels (Fig. 4). The film exposed with 75KV presents essentially the same image that the cephalogram does. The film exposed with 45KV shows a thin layer of palatal cortex. At the orthodontic department of the University of Groningen, 23 patients were studied with laminagraphs. All these patients were treated or in treatment with the Begg Technique. They were divided into groups, in accordance with when the laminagraphs were taken: A. At the start of Stage III B. Immediately after treatment C. Six months after treatment D. 12-24 months after treatment E. 2-5 years after treatment Of the 23 patients, 19 ranged in age from 11-15 when treatment was initiated and the remaining four were 17-24 years of age. The majority were Class II division 1 malocclusions, but three were Class II division 2. The ANB angles ranged from 4 to 10 degrees. Case Observations There are several interesting cases in Group C (six months posttreatment). Case F.B. was a female, aged 11 years 7 months when treatment was begun. The malocclusion was a Class II division 1 with a deep anterior overbite and a severe protrusion (14mm). The four first bicuspids were extracted and treatment lasted 28 months. In examining the visible aspect of the palatal cortex in the different stages of treatment as traced from cephalometric films (Fig. 5), note the relative position of the maxillary incisor to the palatal cortex, particularly at the beginning of Stage III and at the end of 65

treatment, and the details of overall tooth movement. Ideal torquing had not been attained. The crown was moved forward and it extruded. Its root sheared downward along the remaining border of the palatal cortex. At the end of treatment, the axial inclination of the maxillary incisor to SN measured 101°, indicating that torquing was not overdone. The cephalometric tracing shows some shortening of the palatal cortex, but the laminagram (Fig. 6) reveals a thin sliver of cortical bone that can be tracked downward along the lingual of the tooth. The laminagram also reveals a peculiar root resorption, beginning at the apex and extending along the lingual surface. It is unlikely that a routine cephalogram would show this type of detail. Case R.W., 20 years old at the start of treatment, presented a Class II division 1 malocclusion complicated by a marked maxillary protrusion (16mm). The four first bicuspids were removed and active treatment lasted 28 months. The cephalograms demonstrate the visible aspect of the palatal cortex and the superimposition again reveals a lack of true lingual root torque of the incisors (Fig. 7). Here too, there was a downward and forward translation of the crowns. The usual objective in torquing is to place the long axis of the maxillary central incisors to SN at 105°, plus or minus 5°. In this instance, the long axis was only at 76° and hence the teeth were in unfavorable positions in relation to the remaining palatal cortex. In spite of its rather peculiar position, the palatal cortex was able to remodel to this tooth movement. The laminagram (Fig. 8) reveals a thin line of cortical bone dropping down in an unusual angle to the original cortex. Also noted was a characteristic kind of root resorption, a reduction in the root end on the labial apical border. This might have been caused by the tipping action, which thrusts the root ends against the labial plate. Similar responses were seen in other cases in which significant amounts of tipping of incisor crowns had been accomplished. Case HB was a male aged 13 years 8 months when treatment started. It was a Class II division 1 malocclusion with a deep anterior overbite and a maxillary protrusion (10mm). The four first bicuspids were removed and treatment lasted 28 months. The cephalometric tracings reveal the position of the maxillary incisor relative to the palatal cortex and the various completed tooth movements (Fig. 9). The long axis of the maxillary central incisor was placed at 103° to SN. The shortening of the visible aspect of the palatal cortex was apparent. However, a laminagram (Fig. 10), demonstrated the existence of a thin layer of palatal cortex bone, as well as the type and amount of root resorption. Case MP was a female aged 24 years 6 months at the start of treatment. The malocclusion was a Class II division 1, with an overjet of 12mm. The four first bicuspids were extracted and treatment took 24 months to complete. The unfavorable position of the maxillary incisor to begin torquing is clearly evident in the cephalometric tracing (Fig. 11). The remaining palatal cortex was practically on top of the incisor apex. Here too, there was the anticipated downward and forward crown movement and very little, if any, real torque. On the cephalogram it appears that the palatal cortex is continuous with the labial cortical plate. However, the axial inclination of the maxillary incisor to SN is 90° and it is apparent that the objectives of treatment were not attained. A dramatic story is seen in the laminagram (Fig. 12). There is a significant notch on the lingual root surface. The palatal cortex attempts to follow the notched configuration. The area of the notch probably represents the contact point of the root and the cortical plate prior to torquing. If one examines the laminagram carefully, some root resorption can also be seen on the labial aspect of the apex. Conclusions After a study of the laminagrams and cephalograms used in this investigation, three important conclusions were arrived at: 1. There seems to be a characteristic type of root resorption, extending from the apex of the root, along the lingual root surface, sometimes accompanied by notching and scalloping. 66

2. It has been assumed that Stage III mechanics routinely produce "true" lingual root torque. This study makes this assumption questionable. 3. There is evidence that a palatal cortex will establish itself approximately six months after treatment, no matter how extensive the tooth movement had been in a lingual direction. Let us examine each of these conclusions. Root Resorption Root resorption is and has been a major complication and problem in orthodontics. In spite of extensive research and investigation15 the exact etiology remains obscure. Gaudet7 and Reitan8 conducted some interesting experiments on tissue reaction following light wire root torque. Gaudet found, in a project on monkeys using Begg torquing mechanics, there were numerous areas of root resorption on the pressure side. The deeper areas of resorption were found in the apical two-thirds of the root. Reitan, using a light wire torquing arrangement on dogs, found a significant root resorption on the pressure side, halfway from the alveolar crest to the apex. Both Reitan and Gaudet concluded that a force level exerted at the peak of the torque loop amounting to less than four ounces, or below 70 grams, caused little or no root resorption. It might seem logical to conclude from these studies that excessive force can be a causative factor for root resorption. However, at the Orthodontic Department of the University of Groningen, every torquing auxiliary is custom-fitted. Commercial products are never used. The amount of pressure incorporated into the torquing loops or spurs is dependent on the extent of the lingual inclination of the incisors. The forces exerted are kept within the range suggested by Gaudet and Reitan, whose findings correlate well with the mechanical typodont experiments of Connelly and Kahler.9 Since much care is taken to minimize and control pressures in Stage III, it would be improper and illogical to blame excessive torque forces for the amount of root resorption seen in the laminagrams. There is reason to believe that root resorption may be dependent upon the position of the maxillary incisors and their relation to anatomical structures prior to torquing . Monitoring Root Torque in Stage III While observing the progress in Case MP, a decison was made to monitor root torquing in Stage III with cephalograms. For this purpose, a lead shield was constructed, 4mm thick and coated on both sides with aluminum. It was connected to the cephalostat and the patient seated behind it, with his face positioned within an opening in the lead shield (Fig 13). If only the maxilla and mandible are to be radiographed and greater precision is desired, a smaller lead shield is connected to the larger one and held with magnets. It can be moved in all directions. If it is necessary to identify smaller, thinner bony areas such as the palatal cortex, the KV level is reduced from 90 to 70. Prior to taking any of these x-rays, the authors sought assurance from the Institute of Radiology at the University of Groningen of the safety of exposure of patients to this radiation. It was discovered that a standard headplate, with 90 KV and 320 mAs at 12 feet, gives an exposure of 120 mR. The partial headplates, with 70 KV and 100 mAs at 12 feet, creates an exposure of only 20 mR. Another interesting comparison is with the periapical radiograph, which has an exposure of 600mR. This investigation indicated that the patient was well protected when the lead shield was used. There was also less scatter radiation. It was deemed safe to make a partial headplate once a month (Fig. 14). With this type of "partial headplate" it is not complicated to superimpose the maxilla on the palatal plane and the mandible on the symphisis. Thus, a methodology for following tooth movement on a regular, serialized basis was instituted. This system of monitoring is demonstrated on Case RK (Fig. 15). The four first molars had been extracted because of decay. There was an extreme maxillary protrusion (20mm). Stage III was reached after 8 months of treatment. Note the 67

position of the lingually inclined maxillary incisor in its relation to the remaining cortical plate at that time, and see the change in its position during torquing at intervals of 5, 7 and 6 additional weeks (Fig. 16). It appears to the authors that the apex first approximates the dense cortical plate after 5 weeks; then the incisor slides downward and forward on a fulcrum closer to the apical region. When torquing was discontinued, the apex of the tooth was on the cortical plate. The overall tooth movement (Fig. 17) indicates there was little or no true lingual root torque. The laminagram (Fig. 18), completed six months after discontinuing lingual root torque, shows a scalloped area in the apical region. A thin palatal cortex can also be seen. Treatment for this case lasted 17 months. Additional cases, monitored in this fashion, displayed similar responses. In another case (Fig. 19) the maxillary incisors responded favorably to the initial torque force, then remained at a standstill for several months, and finally finished with a downward and forward movement. The information obtained from the series of partial headplates, tracings, and laminagrams raises questions about torquing and tooth movements prior to torquing. These are: 1. Does excessive tipping of the maxillary incisors create an unfavorable relation to the palatal cortex, perhaps caused by incisal extrusion, which in turn may be aggravated by continued Class II elastic traction? 2. How much true lingual root torque can be expected when the palatal cortex is close to the apical region of the incisors? Reitan8 stresses the importance of the density of bone. Lamellated bone is more difficult to resorb with orthodontic pressure than bundle bone. It must be remembered that Reitan and Gaudet did their research on teeth which were in normal relation with the dental arch. They did not torque within a treatment program that would first lingualize, then upright incisors. Excessive Lingualization of Maxillary Incisors The authors believe that excessive lingualization of maxillary incisors may be a questionable procedure. Translating Reitan's findings to such situations, it appears that torque forces create a zone of hyalinization in the area where the remaining dense cortical plate meets the lingual root surface. This hyalinization zone acts as a fulcrum and, as the torquing auxiliary dissipates its action, a forward and extruding crown movement results. This hyalinized area will become reorganized and cause root resorption. Then there will be another hyalinized zone immediately formed, because of the angular relation of the incisor against the dense laminated palatal cortical plate. This reaction will keep repeating itself and, as a consequence, there will be a shearing downward and forward of the incisor along the dense cortical plate, resulting in a typical root resorption. As Reitan states8, "Once root resorption is started, even pressures exerted by fibrous tissue against the resorbed root surface tends to maintain or increase the resorption process." Continuous studies of laminagrams indicate the density of bone may be a causative factor for root resorption. It may be totally unfavorable to reposition an incisor against the cortical plate, as this position would cause hyalinization in an area where, under normal conditions, hyalinization will occur during torquing. In an investigation to record the incidence and degree of root resorption in cases treated with the Begg technique, Goldson and Henrikson11 found a high frequency and more severe root resorption on the maxillary central incisors that were torqued for lingual root positioning. Their studies were done with intraoral periapical films taken in a labiolingual direction. Therefore, the amount and kind of resorption that occurred could only be identified in the mesiodistal plane. The laminagrams presented in this report show significant root resorption on the apicolingual surface. The assumption that the fulcrum during torquing with Begg auxiliaries is within the bracket may be correct. However, the authors believe that this can be significantly altered by anatomical relationships. During treatment, teeth may be positioned against anatomical barriers prior to torquing. In such instances, as determined with laminagrams, an 68

"anatomical fulcrum" is established. This fulcrum does not have a fixed position, but seems to glide apically as the incisors elongate. Close inspection of Figures 13 and 19 reveals an anatomical fulcrum in the deep scalloped resorbed areas. In a recently published paper on Begg technique12 one of the causes mentioned for a deepening of the bite and the reappearance of an overjet was excessive torque force. However, in the same paper, the contention was made that insufficient torque may be due to too little force being applied. The cases described indicate that the main cause of the problems was lingualization of the incisors into unfavorable positions; and that the mechanotherapy is limited and somewhat controlled by the anatomy. The Begg technique has many attractive features for the treatment of malocclusions, but the requirement to tip the maxillary incisors lingually to an excessive degree is a questionable one. Remodeling of Palatal Cortex A remarkable fact revealed by the laminagrams is the presence of a palatal cortex, despite extensive tooth movement in a lingual direction. This is a gratifying discovery, since orthodontists have been asked if they are moving teeth through the lingual plate.6 In patients six months post-treatment, where no palatal cortex could be seen on cephalograms and the tracings indicated that the incisors were through or outside the visible cortex, laminagrams revealed the presence of a thin layer of new cortex. In the group of four cases where laminagrams were made at the beginning of Stage III and the central incisor is against the dense cortical plate, even where incisors were tipped markedly lingually there is a sliver of bone extending to the cemento-enamel junction (Fig. 20). In the group of seven patients where laminagrams were made immediately after treatment, no palatal cortex could be detected (Fig. 21). The tracing showed extensive tooth movement to attain treatment objectives. In all probability, the bone present prior to torquing was resorbed and therefore, at this point in treatment, a palatal cortex does not exist. However, there will be osteogenesis. Otherwise, there would be severe mucogingival retraction on the palatal surface. Perhaps the laminagrams of this group could be correlated with the histological findings of Wainwright13 when he deliberately moved the roots of premolars through the buccal cortical plate in monkeys. He observed that in the perforation sites, the periodontal ligament and the periosteum merged to become continuous and lay between the root surface and the overlying buccal soft tissue. In this zone, many osteoblasts became visible. There is reason to believe that, in our cases, immediately after treatment there is such a merged zone with osteoblasts which form a new palatal cortex in approximately six months. The new palatal cortex is not comparable to the original cortex. It is a thin, irregular sliver of bone. It will take several more years of observation to learn what happens later on. However, all six cases in Group D (one to two years posttreatment) showed a well-developed, curved, dense cortical plate (Fig. 22). When treatment was completed, it is likely there was no cortex. However, within two years, a new one was formed. The laminagrams reveal an area of repaired resorption in the apical region. Relapse of Torque In the group six months posttreatment, 6 of 8 cases demonstrated slight relapse of torquing movement on the tracings of the partial headplates. In the cases one to two years post-treatment, 4 of 6 demonstrated relapse of torquing movement. We now have two cases four years out of retention. In both there had been extensive tooth movement, but now there is a well-defined, dense, curved cortical plate. Both of these cases show a relapse of the torquing procedures (Fig. 23). Observations When laminagraphy is combined with tracings of cephalograms, some interesting lessons can be learned. In cases in which cephalograms and laminagrams show teeth moved through the palatal cortex immediately after active treatment, 69

laminagrams taken six months later reveal a newly formed palatal cortex. Hence, there is no reason to suspect that there will be an irreversible reaction causing damage to the alveolar bone, nor should it be of concern that the newly formed bone is of inferior quality. The laminagrams have proven that there is no anatomical limit to tooth movement in the marginal area of the alveolar process. However, there is a very definite limit to tooth movement of the apex against the palatal cortex. This is clearly demonstrated on a patient (Fig. 24) for whom, in retrospect, treatment with orthodontics alone was not the best procedure. Even though there was extensive tooth movement within the marginal alveolar process, when efforts were made to move root apices, all that was accomplished was considerable root resorption. It seems that after 12 months or thereabouts, a well-curved, dense cortical plate resembling the original one reappears. There is strong evidence that this is associated with relapse of previously attained torquing tooth movements. Might this suggest a physiologic limit to tooth movement determined by function, speech, tongue, etc, as contrasted to the anatomical limits? While the cases used in this study were all treated with Begg technique, which is taught at the Graduate Department of Orthodontics at the University of Groningen, the authors feel that their observations apply to all systems of treatment. It is possible, however, that some of the complications noted were the result of special mechanotherapy requirements of certain fixed appliance systems. In the Begg technique, it appears from the laminagrams and tracings that when the maxillary incisors are tipped lingually so their root apices are close to the cortical plate, additional problems will be encountered in Stage III. The patients who were monitored regularly with partial headplates during Stage III displayed a shearing downward of the root along the dense cortical plate, root resorption and elongation of the crowns. Preliminary investigation of a few cases being treated with the edgewise mechanism indicate some similarity in response. Bodily movement and root torque were questionable as soon as the incisor roots approximated the lingual cortex. Our studies indicate that the major cause of these complications is that orthodontists seem to limit tooth movement within the marginal area of the alveolar process (Fig. 25). Is Intrusion the Answer? Why not take advantage of all the alveolar bone up to the palate? This can be accomplished by intruding the maxillary incisors so that the dense cortical plate will approximate the lingual root surface near the cementoenamel junction (Fig. 26). In such a favorable relationship, torquing forces can function in an optimum fashion. Reports in the literature indicate that it is difficult to intrude maxillary incisors with Begg mechanotherapy. The authors have discovered that, with minor changes in the Begg technique, a significant amount of intrusion of maxillary incisors can be obtained and a favorable relationship of the incisors for root torquing (Fig. 27). At the Orthodontic Department of the University of Groningen, a group of patients are under treatment, utilizing the Begg technique with the modifications to intrude the maxillary anteriors. Preliminary observations reveal some interesting facts: 1. Active intrusion of the maxillary incisors can be accomplished. 2. As the intrusion becomes significant, the overjet is decreased, with resultant soft tissue improvement. 3. The eventual root torque requirements will be lessoned. To validate and document these preliminary observations, this group of patients is being monitored carefully with partial headplates with precision lead shield, which seem to be ideal for this study. 70

The authors also believe that there may be validity and advantages to correct or partially correct severe discrepancies at a younger age, which may negate more extensive tooth movement at a later age. Summary A group of 23 patients were monitored and studied. 27 laminagrams taken on this group revealed: 1. Immediately after orthodontic treatment, a palatal cortex could not be detected. 2. Approximately six months after orthodontic treatment, a palatal cortex could be detected, although in most cases it was a thin irregular sliver of bone. 3. From 1-5 years post-treatment, the palatal cortex seems to have remodeled and reshaped to resemble a normal cortex. 4. Relapse of the incisor roots seems to be associated with the reshaping of the cortex. The development of the lead shield and partial headplate helped in studying the relationship of the maxillary incisors to their surrounding anatomical structures, and this knowledge should help in the development of more efficient mechanotherapy for torquing procedures. It becomes essential to recognize that routine orthodontic tooth movement may have anatomical and physiological limitations. If the objectives of treatment are beyond these limitations, surgical intervention may be required to attain these goals. Excessive lingual tipping of the maxillary incisors may create future treatment problems. Greater emphasis should be placed on intruding maxillary incisors. ACKNOWLEDGEMENT — The authors wish to thank the following people for their generous assistance in the preparation of this paper: R.L. Dijkstra, P. Hartevelt, K.J. Poel, Photography Department, University of Groningen. Prof. J.R. Blickman, H. van der Zwaag, Institute of Radiology, University of Groningen. Mr. van der Pol, Institute of Instrument Fabrication, University of Groningen. Els-Marjan Groenman, Jan Boersma, Department of Orthodontics, University of Groningen . The authors are especially indebted to Dr. Sidney Brandt, Morristown, N.J. for his counsel and guidance in the preparation of this manuscript.

Ref Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1976 Nov(804 - 822): The Effect of Antero-Postero Incisor Repositioning on the Palatal Cortex as Studied with Laminagraphy. -------------------------------1. Baumrind, S.: A reconsideration of the propriety of the "pressure tension" hypothesis. Am. J. Ortho. 55:12, 1969. 71

2. DeAngelis, V.: Observations on the response of alveolar bone to orthodontic force. Am. J. Ortho. 58:284, 1970. 3. Barrer, H.: Limitations in orthodontics. Am. J. Ortho. 65:612, 1974. 4. Schudy, F.: JCO Interview. JCO 9:495, 1975. 5. Duterloo, H.S.: The impact of orthodontic treatment procedures on the remodeling of alveolar bone. In Studieweek 1975, p. 5-21. 6. Edwards, J.C.: A study of the anterior portion of the palate as it relates to orthodontic therapy. Am. J. Ortho. 69:249, 1976. 7. Gaudet, E.J. Jr.: Tissue changes in the monkey following root torque with the Begg technique. Am. J. Ortho. 58:164, 1970. 8. Reitan, K.: Effects of force magnitude and direction of tooth movement on different alveolar bone types. Angle O. 34:244, 1964. 9. Connelly, H. and Kahler, J.: Static analysis of the face— Angle relationship of auxiliaries in torquing and uprighting with light wire procedures. Thesis, Columbia University, 1967. 10. Kustra, S.: Personal communication. 11. Goldson, L. and Henrikson, C.: Root resorption during Begg treatment: A longitudinal roentgenologic study. Am. J. Ortho. 68:55, 1975. 12. Cadman, G.: A Vademecum for the Begg technique: Technique principles. Am. J. Ortho. 67:601, 1975. 13. Wainwright, M.: Faciolingual tooth movement: Its influence on the root and cortical plate. Am. J. Ortho. 64:278, 1973. 14. Swain, B. and Ackerman, J.: An evaluation of the Begg technique. Am. J. Ortho. 55:668, 1969. 15. Newman, W.: Possible etiologic factors in external root resorption. Am. J. Ortho. 67:522, 1975.

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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1972 Mar(133 - 156): Begg Auxiliaries An Evaluation and Clinical Application --------------------------------

BEGG AUXILIARIES An Evaluation and Clinical Application ALAN E. BARBIERI, DDS, MS FRANK R. BARBIERI, DDS, MS INTRODUCTION Since the introduction of the "light wire technic," by Dr. Begg in 1956, this seemingly simplistic treatment approach has been criticized and analyzed and innovated beyond recognition. The early cliches, "It seems to work out" and "Don't worry about it" were soon quieted and replaced by "How do you alter the mechanics in this situation?" It would be fair to say that the conventional stages and treatment technic are applicable in a majority of cases. These are not, however, the cases which cause orthodontists the problem. It is the exception and the application of variation to the exception that tests the skill and knowledge of the operator. When, how and why to vary treatment approaches results from a thorough understanding of the routine mechanics and force application. Dr. Begg has said: The light wire technique is unique among orthodontic treatment techniques in that success with it is dependent upon the employment of the correct amounts of toothmoving forces throughout its three stages. Adherence to this principle of the employment of no other but the correct amounts of force is of paramount importance in relation to anchorage control. Also, as has already been explained, orthodontic force values must be varied according to which teeth have to be moved, and according to which teeth have to be prevented from moving.2 The application of this point is paramount to success in varying the mechanics in specific situations. It is not our intention to present an exclusive approach to treatment problems. We wish to present a procedure which produces a minimum of undesirable changes within the confines of our treatment philosophy and the principles of the Begg technic. Dr. Begg concluded in his text: Do not succumb to innovations. Ask to see results first. If results are available, carefully examine the models and find if any requirements of proper treatment have been neglected. If all requirements are not properly met ignore the

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innovations so that you will not be confused. If all requirements appear to be met, make further investigations to find whether the innovations are only complicated ornaments or real improvements.2 We invite you to evaluate this presentation in this frame of reference. AN EVALUATlON OF LIGHT WIRE AUXILIARIES Analysis of Paralleling Auxiliaries The paralleling auxiliary commonly referred to as an uprighting spring is used to perform root movements or to create resistance to crown movement. It is basically a modification of the total Begg appliance to permit individual tooth movements. Generally speaking, the paralleling auxiliary is a helical spring with a stem to engage the pin channel of the light wire bracket and an activating arm which attaches over the archwire. Some things basic to the force system employed when using a paralleling auxiliary are the following: 1. Gauge of the wire used 2. Resiliency of the wire used 3. Size of the helix used 4. Number of the coils in the spring 5. Direction of activation The complicated physics involving each of these factors must be viewed, keeping in mind that teeth respond to a range of tooth-moving forces and that time plays an important role in tooth movement. It is therefore necessary to understand the forces being used and the opposite reactions to all forces used. Recently the authors researched some new aspects for the use of the molar paralleling auxiliary. Based on the concept that paralleling springs could be adapted for use as braking auxiliaries, experiments were conducted to test the feasiblity of using molar springs to serve as an additional anchorage force. The use of this additional anchorage potential would be indicated in: 1. Maximum anchorage cases - springs can provide additional anchorage. 2. Borderline non-extraction cases - springs can provide additional anchorage. 3. Bimaxillary protrusion cases - springs used on both maxillary and mandibular molars will permit better use of extraction space for anterior retraction. 4. Molar or second premolar extraction cases - springs can be used to help offset the strong mesial force brought about by the paralleling movements of cuspid and premolar roots distally. 5. Open bite skeletal cases - springs can be used where the extrusive forces of Class II elastics or anchorage bends must be limited. Previously, when springs were used in the molar tube, the stem of the spring was inserted into the distal of the molar tube with the activating arm passing gingivally to the molar tube and engaging on the archwire mesial to it (Fig. 1). With the introduction of a buccal tube incorporating a vertical jot in the basic design, the operator has the option of using this vertical slot to house the stem of a molar spring (Fig. 1).

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The shortcomings of using a molar spring inserted into the distal of the molar tube were explored by Swain.4 The physical lack of space present when an .016 spring arm and an .016-.020 archwire occupy the lumen of an .036 buccal tube is obvious. The congestion can negate the action of the spring. Using the vertical slot eliminates this problem, allowing a better range of action more typical of a braking spring used in a cuspid tooth. To verify this thinking an apparatus by Swain4 was used (Fig. 2). The test apparatus consisted of a board securely holding four Correx measuring gauges. A demonstration tooth with a molar tube was suspended by four wires from the gauge. The wires were connected to the mesial cusp, distal cusp, mesial root apex and the distal root apex respectively. The readings of gauges connected to the mesial cusp and mesial root were most indicative of vertical displacement and mesial root thrust respectively. As each of the following test situations were created, changes in the four gauges were noted on a chart. The following combinations were tested (Table I): 1. The force generated by a 20° anchorage bend in an .020 arch. 2. The force generated by a 40° anchorage bend in an .020 arch. 3. The force of an .016 molar spring inserted through the distal of the molar tube with no anchorage bend. 4. The force of an .016 molar spring inserted through the vertical slot of the buccal tube with no anchor bend. 5. Steps 3 and 4 were repeated using an .020 arch with a 20 degree anchor bend.

The conclusions drawn from these measurements are that: 1. use of a molar spring increased the anchorage potential of the molar tooth. 2. this effect was in addition to the anchorage potential of the anchorage bend. 3. using the vertical slot allowed for better action of the molar spring. 4. using the vertical slot not only increased the anchorage potential of the molar, but did so with considerably less vertical displacement of the test tooth. Based on the results of these tests some variations in treatment procedures have been introduced for use in some specific cases. Further discussions of this material will be included in the stage by stage review later in this paper. However, at this time it would be of interest to discuss the specifics involved with the application of a molar paralleling auxiliary in the vertical slot. An .016 spring with a long stem and long activating arm is used (Fig. 3). The stem can be shaped to permit easier insertion into the vertical slot. The angle of activation can be varied but a range of 20° to 40° seems adequate to create molar anchorage (Fig. 3). The helix of the spring should bring the activating arm away from the buccal surface of the tooth. This will keep the activating arm parallel to the arch and will prevent the introduction of any rotational forces (Fig. 4). Since there are a wide variety of paralleling auxiliaries available to the orthodontist, it is appropriate to discuss the features necessary for their selection for use in the Begg bracket. Upon close examination, there are distinct and important differences in these auxiliaries, among which are the size of the helix, length and offset of the channel arm, number of coils, length of the activating arm, diameter of the wire and offset of the hook (Fig. 5). The auxiliary on the left in Fig. 6 has a large helix with three coils. Note also that the engaging hook has been offset so that the hook, coil and base arch would be parallel when placed in the mouth.

75

The auxiliary on the right in Fig. 6 shows that the free end of the engaging hook extends beyond the activating arm. When used clinically, this would necessitate raising the activating arm above the base arch in order to engage the hook. This tends to close the coils and decrease the activation. In Fig. 7 we see that when the hook is not offset, the activating arm must be brought buccally to be activated, thus creating some rotational effect. Note, also that if examined from the buccal, the arms would appear not to be touching, however, they could be contacting at their free ends, just lingual to the base arch. Fig. 7 also shows these factors are eliminated when the hook is offset. The same apparatus was used to evaluate the forces created by an "Archimedes" or reverse engaging spring. In many minimum anchorage cases demanding a good deal of vertical correction, the orthodontist found that the use of cuspid braking springs impeded bite opening. In evaluation of this problem Swain5 felt that, if the Archimedes type spring did indeed cause intrusion rather than extrusion, it could be used as a braking spring in the above mentioned cases. Testing (Fig. 8) showed that the force created with the use of the Archimedes type spring was truly intrusive (Table II). It would therefore seem plausible that when braking springs are needed in deep overbite cases requiring a good deal of vertical correction the Archimedes type spring would be the spring of choice. No clinical data has yet been accumulated but evaluation is under way. Analysis of Torque Auxiliaries The palatal movement of the maxillary central incisor roots combined with the distal and palatal movement of the maxillary lateral incisors is commonly referred to as anterior root torque or just simply torque. To achieve these movements, several auxiliaries have been developed. The spur type auxiliary employing either two or four spurs and the wing type are the most commonly used torquing auxiliaries (Fig. 9). Choice of a torquing auxiliary must be based on the specific needs of each case as assessed by the orthodontist. However, some reactions basic to the use of torquing auxiliaries should be discussed. The two most common reactions to torque auxiliaries are depressions and flaring of the maxillary buccal segments. Swain5 considers the depression of the buccal segments a direct reaction to the palatal root movement of the maxillary central incisors and flaring of the buccal segments a result of torque force on the maxillary lateral incisors. The wing type auxiliary causes expansion in the cuspid area. Additional information about the use and activation of torque auxiliaries along with consideration in base arch construction will be found later in this paper. CLINICAL APPLICATION OF LIGHT WIRE AUXILIARIES Stage I Of the three stages of treatment, this stage rarely necessitates the use of auxiliaries. This is largely due to the fact that most cases require bite opening and maxillary anterior retraction. These objectives respond to the tip-back arch and intermaxillary elastic mechanisms. There are, however, particular situations that require the application of auxiliaries. This application can be broken down into two broad categories: anchorage considerations and skeletal considerations. In minimum anchorage cases where extractions were performed, there is a need, many times, to prevent the lower anteriors from "over-retracting". The application of uprighting springs in the mandibular cuspids (Fig. 10) increases resistance anteriorly and enhances the mesial movement of posterior segments. Our clinical experience in the application of "differential force" by the use of heavier elastics has not been good. That is to say, increasing horizontal and Class II elastics to 5 or 6 units (on Dontrix gauge) did not cause mesial movement of posterior segments without additional mandibular anterior retraction. Therefore the alternative of adding an auxiliary to the system is preferred. The "hyperdivergent," "high angle," or "skeletal open bite" case requires application of the previously quoted cardinal point of Dr. Begg; that is, varying orthodontic forces in relation to which teeth have to be moved. The use of conventional 76

mechanics can further aggravate the existing disparities because of extrusive force generated by Class II elastics and tipbacks in the archwire. The recommended procedure is to use no tip-back in the archwire or sufficient to maintain the bite edge to edge. Clinically this proved to be more easily said than done. In many cases after a few months the mandibular molars were severely tipped forward by the Class II elastics. This required the removal of the arch and the introduction of some tipback. If too much tip-back was placed the bite would open; if insufficient, the molar would not upright. The result was both frustrating and time-consuming. An array of alternatives were suggested, ranging from extraoral traction, lip bumpers and, as suggested by Dr. Begg, extraction of eight teeth. The first two procedures again bring up the factors of patient cooperation and compatibility with Begg mechanics; the third, a lack of compatibility with a personal philosophy. As described earlier, the molar spring can be an acceptable alternative. One, control of the mechanics is maintained by the orthodontist; two, cooperation is not a factor since no visible or additional appliance is necessary; three, there is tooth conservation; four, the undesirable effects of the tip-back are eliminated while maintaining the molar in an upright position. To illustrate these points, two cases are presented: K.B - Figs. 11-13 and T.W. Figs. 14-15. Stage II As previously outlined the use of mandibular cuspid "braking springs" or "molar springs" is usually continued through Stage II. If not previously used, they may be introduced in this stage when clinical indications arise. Stage III One of the problems that concerned many orthodontists using the Begg technic was control of tooth movements during Third Stage. Many operators experienced faring of the maxillary buccal segments, depression of the cuspids and bicuspids and other undesirable tooth movements. This meant removing and adjusting the base arch with its resultant loss of chair time, lengthening of treatment time or use of unusual elastic positions for this stage, such as cross elastics or cross palatal elastics. These would only delay the ultimate archwire adjustments that were needed. These complications of Stage III resulted in a prolonged finishing step sometimes referred to as Stage IV. This discussion will demonstrate one approach to Third Stage construction that will; one, minimize chair time, two, increase control of tooth movement and three, practically eliminate undesirable tooth movements. Ideally, the Third Stage can be started when there is a Class I or slightly Class III molar relationship, edge to edge relationship in the anterior segment with a slight open bite and all spaces are closed or nearly so. However, the individual tooth position and arch configuration may not be desirable for the beginning of Stage III. The objectives of the Third Stage is the correction of the axial position of all teeth. Most commonly this is lingual root torque of the maxillary incisors and paralleling of bicuspid, cuspid and lateral incisor roots. The Third Stage construction is divided into two distinct steps. One, base arch construction and two, placement of auxiliaries. The reasons and purposes for this division will become apparent later. When Stage II is completed or nearly so, the patient is given a half-hour appointment for archwire construction. Keep in mind throughout this discussion, that the basic strap-up consists of .036 vertically slotted molar tubes, light wire brackets with an .020 pocket width and lingual cleats on cuspids, bicuspids, and molars. The patient's initial models are always present during base arch fabrication. The archwire used is .020 Australian wire. It may seem that this diameter wire is incompatible with a light wire technic. However, you may recall that when the technic was first introduced, the base arch was .016 and due to the reactive forces of the auxiliaries many distortions appeared that had to be compensated for. As an example, the early maxillary .016 base arch had to be made pear-shaped to counteract the Haring of the molars that the torque arch produced. It was difficult to determine if arch form had been maintained and if the compensations made were sufficient. 77

As the technic evolved, many operators progressed to heavier base arches realizing that all low resistant crown movements were completed and only high resistant root movements remained. Therefore, the .020 base arch serves only to maintain arch configuration in width and symmetry and resist the undesirable reactive forces of the auxiliaries. The arch is constructed so that the anterior segment is gingival to the buccal segments of the archwire in deep overbite cases, and is kept incisally in open bite cases. The anterior segment is shaped and the cuspid offset is placed. Using the cuspid contouring plier, a gentle curve is placed in the cuspid portion of the archwire, thus bringing the buccal portions of the archwire over the buccal cusps of the bicuspid and molar (Fig. 16). This is important as it maintains the proper bicuspid width and alignment. The archwire is checked for symmetry and conformity to arch width in both the patient and initial models. The arch is placed in the buccal tubes and marked so that the molar offsets can be placed at the interproximal of the molar and bicuspid. The offset must always be judged for the individual case since it is actually compensating for the difference in the buccal contour of the bicuspid and molar. An insufficient offset results in pulling the bicuspids buccally. The other arch is constructed and both coordinated. This completes what can be termed the "essential wire bends". An evaluation is now made of both the initial models and the course of treatment to date. Simplest to determine is the toe-in or toe-out as indicated by the rotation of the molars either in the original malocclusion or at the end of Stage II. If the molars are well aligned, no toe-in is placed. With regard to the reverse curve of the buccal segment (Fig. 17), the models are examined to determine the extent of the Curve of Spee in the original malocclusion. The greater the Curve of Spee in the original malocclusion, the greater the reverse curve in the buccal portion of the archwire. If the occlusal plane was flat originally, a slight reverse curve is still necessary to counteract the depressing action of the paralleling auxiliaries. If the lower anteriors show "peaking" or an extruded effect, some reverse curve should be placed in the anterior segment of the arch. Since the effect of the tip-back is least on the central incisors, they will often appear slightly extruded from the occlusal plane. Leveling can usually be accomplished by a Flat anterior segment. However, a very slight reverse curve may be needed. In the maxillary arch, a reverse curve is always placed in deep overbite cases to counteract the extrusive action of the torque arch. Generally the amount of maxillary anterior reverse curve used will cause the wire to pass at the gingival margin on the maxillary central incisors (Fig. 18). The reverse curve in the buccal segments acts to some extent as a tip-back. However, there are factors which do indicate the need for an additional tip-back. They are: mesially tipped molars, poor bite-opening responses during earlier stages of treatment, extremely deep overbite in the original malocclusion, and maximum anchorage cases. This additional tip-back is placed in the molar offset bend. At the base arch construction appointment bracket height corrections should be made and any lingual cleats lost during Stage I and II replaced. The arches are placed and pinned tightly and the patient is given a half-hour appointment in three to four weeks. R is important to allow this period to intervene before placing the auxiliaries. This permits tooth response and full seating of the arch in the bracket pockets and allows the operator to evaluate the need for altering the secondary modifications prior to placing the auxiliaries. When the patient returns, he is examined to determine if any further modifications in the base arches are necessary. After the pins are removed from the bicuspids and cuspids, the base arch should be passive, and fully seated in the bracket pocket. Now, when the auxiliaries are placed, they will passively close off the gingival position of the bracket pocket and will not actively hold the base arch in the pocket. The paralleling auxiliaries are placed and the channel arms bent over in the direction of the activating arm. The auxiliaries should be examined and adjusted so that the activating arms are approximately the same angle to the archwire. In this way, they will deliver approximately the same force. Theoretically with the auxiliaries adjusted in this manner, there would be no mesial force on the arch in first bicuspid extraction cases. 78

In the second bicuspid and molar extraction cases, the paralleling auxiliaries will produce a net mesial force on the arch. In addition, the torque arch and the use of Class II elastics cause serious anchorage problems. In molar extraction cases, the reverse curve in the buccal segment should only be slight, since an excessive curve will cause the occlusion to be supported on the bicuspids only and can result in no occlusal contact of the molars. Therefore, other compensations are necessary. There must be maximum retraction during Stage I and II. The base arch should have additional tip-back. It has also been desirable to place a paralleling auxiliary in the molar vertical slot (Fig. 19). It should be remembered, "preformed" is not a guarantee of "precision". All auxiliaries must be carefully checked when being inserted. The torque arch used, is generally of the Kitchton type. However, the individual loop type is still preferred in cases where torque is apt to be needed over an extended period of time. No torquing devices that are an integral part of the base arch are ever used. The lingual ties generally used are either steel ligatures or the Alastik chains. One must be careful when using the Alastik. Whereas the steel tie is generally a passive tie, the Alastik chain is initially an active force, and can cause undesirable rotations of the molars. However, after a few weeks, they are passive. Generally four loops are needed from cuspid to molar and preferably placed on the lingual. In addition, ligature ties are placed from the distal to the cuspid bracket through the intermaxillary hook to prevent any anterior spacing. All the auxiliaries are not necessarily placed at one appointment. In the typical first bicuspid extraction case, the buccal paralleling auxiliaries and torque arch may be placed, however, the incisor auxiliaries are usually not placed until the last two months of Third Stage. In maximum anchorage, second bicuspid and molar extraction cases, simultaneous paralleling and torque is rarely done. Dividing paralleling and torquing decreases the need for Class II elastic usage and anchorage strain, but does lengthen the total time for Stage III. Clinical judgment of the individual case should dictate the use of auxiliaries, not a "cook book" approach. Generally patients are seen at four to six week intervals during Third Stage, which lasts approximately eight months. When all corrections are completed, the auxiliaries are removed, the secondary modifications removed from the archwires and the finishing stage begun. The finishing procedures with the fixed appliance is completed in three to six weeks. The case is then evaluated to determine the need for a tooth positioner or simple retainers. Although the scope of this presentation seems limited, it is obvious that all types of cases and treatment ramifications could not conceivably be covered. It is hoped that the essentials of mechanotherapy and criteria for clinical evaluation will enable the practitioner to apply clinically the procedures outlined here.

Ref Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1972 Mar(133 - 156): Begg Auxiliaries An Evaluation and Clinical Application. -------------------------------1. Barbieri, A. E. and Barbieri, F. R.: Table Clinic Presentation; Begg Society Meeting, Montreal, Canada, Sept. 1971. 2. Begg, P. R.: Begg Orthodontic Theory and Technique, Phila., Penna., Saunders, 1965. 3. Begg P. R.: Discussion Period Begg Society Meeting, Montreal, Canada, Sept. 1971. 4. Graber, T. M.: Current Orthodontic Concepts and Techniques, Phila., Penna., Saunders, 1969. 5. Swain, B. F.: Personal Communication 79

Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Aug(526 - 538): 8-Tooth Extraction Cases Using Begg Technique --------------------------------

8-Tooth Extraction Cases Using Begg Technique LYMAN E. WAGERS, DDS Where required, 8-tooth extraction treatment is the finest service that the orthodontist can render, but the orthodontist must make the treatment plan and treatment decisions carefully. He must be alert and especially watch molar control. 8tooth extraction cases are rare and only occur in about 0.5% of our cases. The cases that are illustrated here were diagnosed by competent orthodontists as being untreatable or needing radical surgical repositioning of the maxilla or mandible. Rationale We measure tooth material and compare it to available arch length or we do a setup and try to determine, if we remove four teeth, whether we can expect to move the anterior teeth back far enough in relation to the AP line. In most of these cases, the upper incisors can be as much as 1.5mm ahead of the AP line. If it is not be possible to retract the anterior teeth back far enough by the removal of four bicuspids, we have still not solved the patient's problem. Our goal is to have 80

the mandibular incisor crown within ±2° of the AP line, with the maxillary incisors creating an interincisal angle of 130° and approximately 100° to SN. If we consider removing only first molars, since they are larger, we are not going to be able to move the anterior teeth back far enough either, because second molars will move faster anteriorly during treatment than the anterior teeth will move posteriorly. Ordinarily, removal of second bicuspids or first molars permits less reduction of the anterior teeth. Therefore, when required, we extract a combination of first bicuspids and first molars, simply because there is not any other way to move the anterior teeth back far enough. Cases requiring extraction of eight teeth are high mandibular plane angle problems. There is no room in the posterior part of the angle for the posterior tooth roots to be moved back. Because of this, they will tend to gradually move forward down the lower arm of the angle, aided by mesial migration. Our decision is made when we decide it is not possible to treat the case, except by removing enough tooth structure to enable us to move the anterior teeth back to the proper position in relation to the AP line. The appliance setup is essentially the same, except that we will band second molars and use retaining rings on the second bicuspids. First stage archwires will be the same. In years past, we used to double the archwire back on itself in these cases and placed it in an oval buccal tube to prevent a tendency to roll. Proper molar control is still a problem in 8-tooth extraction cases, because molars can very easily tip in mesiolingually toward the tongue. If this is allowed to occur, it will create a need for extra tooth movement to correct the problem. An additional problem in 8-tooth extraction cases is that, even though the patient tries to be careful, there are plenty of chances to bite an unwanted bend in the archwire. We usually see the patient monthly at first, until we can place heavier archwires that we need not worry about so much. CASES Case T.M. This case presented a 14-year-old male with a high angle severe, open bite Class II malocclusion. Case T.M. records before treatment. Four molars and four bicuspids were extracted and the first archwires were placed (September 1968). By May 1969, the case was in Stage II in both the upper and lower arches; and by September 1969, most of the space had closed. We did a clean and check procedure in February, 1970 and when the appliances were replaced, Stage III archwires and uprighting springs on the second molars and second bicuspids were started. We attach the molar uprighting spring just distal to the second bicuspid bracket and the second bicuspid uprighting spring attaches to the helix of the molar uprighting spring. In that way, it has a double action— depressing the molar distally, while elongating it mesially. The molar uprights more quickly in this way. We use this setup on all 8-tooth extraction cases and all second bicuspid extraction cases. Up and down or vertical elastics are worn most of the time in Stage III and the best arrangement is to wear them from the mesial of the maxillary molars to the distal of the mandibular molars. It takes a long time to upright molars in 8-tooth extraction cases and, if we do not get proper uprighting, we will not have a good result. By December 1970, we were able to remove most of the uprighting springs and the torquing auxiliary. In February 1971, the remaining spring was removed and we ere ready to remove appliances. 81

All appliances were removed in March 1971. Two years later, the case had settled in well and the third molars had erupted into function. Case T.M. Records after treatment. Case P.H. This case presented a 17-year-old male with a severe crowded and protrusive Class II malocclusion. Case P.H. records before treatment. Molars and bicuspids were extracted in May 1971. And the first archwires were placed. The first archwires were on this case for quite a while and the second archwire still needed some loops, because the laterals were not evening out enough. We have, in essence, a Stage I archwire with Stage II elastics, because the teeth are end-to-end enough for us to use intramaxillary and Class II elastics at the same time. We tend to go into Stage II a little earlier in these 8-tooth extraction cases than we normally do on a 4-tooth extraction case, because we become anxious to reduce the long spans of archwire and minimize the chances of biting an abnormal bend in the archwire. Care must be taken against being too premature, which can cause a loss of control, forcing extra corrective work unnecessarily. Next, we are using elastics from cuspid to cuspid, in addition to Class II and intramaxillary elastics. Frequently, in 8-tooth extraction cases and in second bicuspid extraction cases, we use elastics from cuspid pin to cuspid pin on both arches and the intramaxillary elastics from the arch hooks to the distal of the buccal tubes. With the Class II elastics, there are 8 elastics being used all together. If there is much anchorage to lose, sometimes we use a large elastic from molar to molar. The cuspid-to-cuspid elastic is just to keep the cuspids from drifting back. We could tie the cuspids to the archwire to prevent this, but we do not tie cuspids to the archwire as much as we did originally. Note that the Class II elastics are attached to the lingual buttons on the lower molars. This counteracts the tendency of the molars to move lingually; but it tends to cause a lingual tilting of the cuspids. So, one must be very careful with the use of elastics to the lingual of lower molars. By March 1972, there was a severe inclination of the incisors; and the bite was not open. In May 1972, a Stage III archwire was placed and Stage III mechanics started on the lower. The bite is not open enough on the upper anteriors and that is why we placed Stage III mechanics in the lower arch first. We do not always put all the Stage III on at the same time and, since the lower cuspid takes longer to upright than the other teeth, we may place the mandibular cuspid springs prematurely. Again, you must use care not to allow other areas to get out of control and into trouble. We have gone back to long-armed cuspid springs, because it is sometimes better to put a depressing effect on the distal of the bicuspid, rather than on the mesial. We now use .016 long-arm springs on practically all mandibular cuspids and we feel they do a better job, although many orthodontists feel that the length of the arm is not as important as the helix. By August 1972, we had gone to the long arm on the lower bicuspids in order to hook it back to the helix on the molar; and we have long-arm cuspid springs.

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We cannot torque the upper incisors yet with the bite closed as much as you see it here, but there is no reason not to get started with torque or uprighting on the lower. Some orthodontists feel they would not get the bite open as long as they are uprighting or torquing on the lower arch, and that the forces would be working against themselves. In this case, we felt that the maxillary teeth needed to be depressed more than the mandibular teeth and we proceeded this way. We finally got the bite open enough to put torque on the maxillary anteriors (October 1972). For a short period, we used Class III elastics because we wanted to get the maxillary anteriors forward and the mandibular anteriors back, in order to let them torque better. In March 1973, we had finger torque on the cuspids. Treatment had moved out ahead in the lower arch and we had taken off the uprighting springs. This is very unusual. Ordinarily, we would just deactivate the springs and leave them there. By September 1973, we had changed torquing springs and eliminated most uprighting springs. In December 1973, the teeth were debanded. One year later, note how the midlines found their way. Case P.H. Records after treatment. We used to worry about centering a midline going into Stage III. Now, we look to the other relationships and do not worry about the midline. I think we would prefer to have this in alignment before debanding, but if the posterior teeth are moved to a correct relationship, the midlines seem to find their correct position. Conclusion I would urge orthodontists to become cognizant of the fact that there are cases in which more than four teeth have to be removed in order to do proper orthodontic treatment. The cases shown had been recommended for surgical repositioning, and I don't think that was correct. Where needed, the extraction of the right amount of tooth structure is less radical than surgical repositioning, which may require almost as much time in banded treatment in addition to the surgery. There are cases that cannot be treated except by surgery; but, on the other hand, there are cases that can be treated by orthodontic tooth movement that are now being referred for orthognathic surgery. So, really, which method is the more radical?

Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1969 Jan(14 - 21): Root Control Methods With The Begg Technique - ALBERT E. MILLER, JR., D --------------------------------

BEGG SERIES PART V Root Control Methods with the Begg Technique ALBERT E. MILLER, Jr., DDS It has been shown that the pure Begg technique utilizes light round archwires and orthodontic attachments incorporating a single point of contact and narrow mesio-distal dimensions for simple tipping tooth movement in all directions in the early stages of treatment (Fig. 1). In the Begg technique all the teeth, with the exception of the anchor molars, are subjected to only simple tipping movements in Stages I and II. 83

A brief resume of the stages of treatment (discussed in detail in an earlier article by Dr. Jean Bertrand) reveals that the more simple types of tooth movement are completed in Stage I and Stage II, crowding and irregularities are corrected, closing of anterior spaces is achieved, overbites are corrected to edge-to-edge relation (except in Class III malocclusions), antero-posterior occlusal relationships are overcorrected, contours of both dental arches are brought to good proportions, and the axial inclinations of the anchor molars are corrected to or maintained in upright position. In Stage II, extraction sites are closed and corrected antero-posterior relationships are maintained. Also in Stage II upper and lower anterior teeth are tipped back to a marked degree which results in the upper and lower dental arches being positioned farther posteriorly in the jaws than before treatment. The movement of the anterior teeth to a position farther back in the jaws at the end of Stage II is accomplished by the closure of the extraction spaces in a manner least likely to move the anchor molars forward. The very light elastic forces employed in Stage II allows for simple distal tipping of the anterior teeth and is too light to move the posterior teeth forward. At the end of Stage II there is noticed a tipping-back or dishedin appearance of the anterior teeth. The central incisors are tipped lingually while the lateral incisors are usually tipped lingually and distally, thus placing the apices of the lateral incisor roots farther mesial than the crowns. Characteristically, in Stage I and Stage II the crowns of the upper and lower teeth are allowed to simply tip in any direction they take while responding to arch wire and elastic forces. The maintenance of correction of the anchor molars to the upright position in Stage I and Stage II is the only incidence of the application of force to prevent simple tipping of the teeth and to effect root control. It is desirable to correct all rotations, midline discrepancies, and open bites before starting root movement procedures (Fig. 2). The purpose of Stage III in Begg treatment is to put all the teeth into good axial relations. This is done by uprighting the teeth and deals primarily with movement of the roots of the teeth. Usually this is the stage of treatment in which the operator must direct the mechanics of treatment to the specific purpose of controlling the movements of the roots of the teeth. Methods of root movement The inherent design of the attachment used in Begg treatment allows for the use of auxiliaries in conjunction with the main archwire. It is through the effective use of auxiliary root-tipping springs and torquing wires that the axial positions of the teeth are controlled. An .016 diameter light archwire is sufficient to accomplish the prerequisites of the first two stages of treatment, but in Stage III, which requires the incorporation of multiple forces, .018 or .020 diameter arch wires are preferred by the author. The large diameter wire has the strength necessary to maintain the ideal arch form achieved in Stages I and II and to act as a base for the auxiliary wires. It is indicated and possible with the Begg technique to employ multi-directional forces simultaneously for the correction of the axial relation of the teeth. The tooth movements performed in the third stage are the torquing of the roots labially, buccally, or lingually as necessary to position the roots in correct axial relations and the tipping of tooth roots mesially or distally as required to correct their axial relations. Root-tipping auxiliaries There have been numerous types of root-tipping auxiliaries employed since the introduction of Dr. Begg's technique to the profession. It is apparent that some types of springs have features which are more conducive to correct force application than others. Experience would seem to indicate that the helical uprighting spring is the most efficient roottipping auxiliary. To produce effective force, the uprighting spring has to be in correct relation to the main archwire and to the tooth to which it is attached. The helices and arms of the spring should be in the- same plane as to the long axis of the tooth and the arch. Incorrect positioning of root-tipping springs creates undesirable forces that will rotate the teeth or tip their roots too far to the buccal or lingual. When utilizing root-tipping springs, the main archwire is ligated to the attachment by either .008 or .009 soft ligature wire to insure that the archwire remains in the attachment during tooth 84

movement. If the main arch is not ligated to the attachment, the auxiliary spring will elevate the tooth occlusally (Fig. 3 and 4). Root-tipping auxiliaries for cuspids and premolars are usually constructed of .014 or .016 diameter wire and consist of a leg to fit through the vertical slot in the attachment, a helical loop, and an arm into which a hook is incorporated running parallel to the main arch. In extraction cases, root-tipping springs should be used on both teeth adjacent to the extraction site. Use of the roottipping springs on the canines only, for example, will cause a mesial drag that will tax molar anchorage. If it is necessary to upright only one of the teeth at the extraction site or if one of the teeth has attained the desired axial position ahead of the adjacent tooth, the spring can be deactivated to a relatively passive state by adjusting the angle of the bend in the arms of the spring. The deactivated spring can thus be utilized to offset the force of the opposing spring and to maintain the position of the tooth to which it is attached. With earlier types of root-tipping auxiliaries, the arms of the springs employed at extraction sites overlapped each other with the hooks positioned over the main arch at the center of the space between the cuspids and premolars. As the teeth uprighted the hooks moved away from each other and toward the opposite tooth (Fig. 5). In more recent procedures, springs with smaller helices and shorter arms which do not overlap have been utilized. The short arms leave enough space for the hooks to move toward each other as the teeth upright (Fig. 6). The springs that have the shorter nonoverlapping hooks and arms theoretically enhance root tipping because of a decrease in friction as the roots move and the hooks slide along the archwire. Another and more recent type of root-tipping spring utilized for cuspids and premolars is a combination of springs whose free arms are encompassed in a round tube running horizontally between the cuspid and premolar. The force application of each spring can be controlled by adjusting the vertical arm of the spring that is inserted in the vertical slot of the attachment. The horizontal arm of each spring thus slides in the horizontal round tube and theoretically allows the arms of the springs to move freely and without friction as the teeth upright. In those cases in which molar teeth have been lost or removed and in cases in which molar anchorage needs to be reinforced, a root-tipping spring can be used for this purpose. One arm of the molar spring is inserted through the .036 buccal tube with the helix at the distal end of the tube while the other arm is hooked over the main arch wire mesial to the buccal tube. The extension of the spring arm protruding through the mesial of the buccal tube is bent occlusally and lingually to rest against the buccal surface of the molar to prevent the natural tendency of the spring to roll around the buccal tube (Fig. 7). All of these root-tipping springs work acceptably as long as they are controlled and kept within the range of force that is compatible with root movement. Although rotation of the teeth in the Begg technique is accomplished by over-corrective bends in the archwires and in many instances by the use of elastic thread ligated to the lingual of the tooth, root-tipping springs can also be modified to create rotating forces to the teeth. The spring employed for this procedure has a small helix and is usually constructed of .014 diameter wire. The helix of the spring is bent at right angles to the vertical leg to place it in a horizontal plane parallel to the archwire. The vertical leg is inserted into the pin slot of the light wire bracket and two ninety degree bends are made in the protruding end of the wire. This end of the wire lays on the labial of the tooth in the direction of the desired rotation and the spring is wound up and activated by hooking the other horizontal arm over the main arch wire (Fig. 8). If a root-tipping spring is used on an incisor, a corresponding spring should be used on the opposite incisor to prevent a shifting of the midline. A mild or passive force in the spring on the opposite tooth will usually suffice as a balancing force. Root-tipping springs are also used in situations in which it is desirable to bring posterior teeth forward. The springs are placed on the cuspid teeth to convert them into anchor units by preventing their crowns from tipping distally. The springs should not be activated. They simply need to be passive to be effective. Activated springs would move the cuspid roots distally and create too much resistance on the part of the anterior teeth. Sufficient force can then be placed on the posterior teeth to move them mesially against the anterior anchor unit created by the uprighting springs on the cuspids. 85

It should be remembered that the force delivered by root-tipping springs depends on the diameter of the wire and the angle between the two arms of the spring. A force in the range of two ounces appears to be the optimum for maximum response. Root-torquing auxiliaries As stated previously, the anterior teeth at the end of Stage II should be tipped lingually and present a dished-in appearance. It becomes apparent at the beginning of Stage III, why it is important to prevent forward movement of anchor molars during the first two stages of treatment. Because of the reciprocal action of the root-moving auxiliaries, there will be an expenditure of anchorage when the roots of the anterior teeth are moved back. Anterior roots are moved back by the use of small diameter auxiliary torquing wires in conjunction with the main archwire. The torquing auxiliary for the maxillary incisors is usually constructed of .014 diameter wire and has incorporated within its form torquing spurs or projections which rest against the labial surface of the teeth at the center of the crowns (Fig. 9 and 10). The torquing auxiliary is constructed to fit in a piggyback relationship to the main archwire and the amount of torque is determined by the angulation of the torquing spurs from the perpendicular. The angulation should approximate 75 degrees (Fig. 11 and 12). The problems usually encountered during root torquing are ( 1 ) undesirable changes in arch form and (2) mesial migration of the posterior teeth. In the first instance, the torquing force that is positively effective against the roots of the anterior teeth is also transmitted negatively along the main arch wire to the anchor molars. The result of the transmission of this force along the wire is to move the anchor molars buccally and to rotate them disto-buccally. To prevent the molars from being so displaced, a heavier main arch (.018 or .02t diameter wire) wire without tip-back bends is utilized. In original techniques, an .016 main arch wire with lingual constriction of the distal arms was utilized to offset the undesirable expansion and rotation. In the second instance, the problem is mesial migration of all the teeth. Excessive torquing forces tend to upset differential force balance and cause a stasis of root movement. The net effect of the stasis is a reciprocal labial crown movement which in turn drags the maxillary posterior teeth mesially. Increasing Class II mechanics in trying to control the migration of maxillary teeth, places excess force on the lower teeth and results in an undesirable forward positioning of these teeth. Therefore it is mandatory that only light optimum forces are used in Stage III in order to produce continuous tooth movement. Optimum torquing force appears to be in the range of 55 grams of pressure and a four degree per month lingual movement of the roots indicates an effective application of root-torquing force. Numerous modifications of root-torquing auxiliaries can be employed to meet the requirements of torquing single teeth or groups of teeth. In some instances root-torquing auxiliaries are placed on the lower anterior teeth to move the roots labially or lingually or to reinforce anchorage (Fig. 13). Following completion of Stage II multiple root-tipping springs and root-torquing auxiliaries can be employed simultaneously to position the teeth in their correct axial relations and to establish correct occlusal function and esthetics (Fig. 14,15,16).

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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1973 Oct(621 - 636): Concept and Commentary: The Extraction-Nonextraction Decision

-------------------------------Concept and Commentary THE EXTRACTION-NONEXTRACTION DECISION Joe A. Sain, DDS When I decide between extraction and nonextraction, I consider, primarily, the degree of crowding and the relationship of the denture to the face. For the relationship of the denture to the face, I rely heavily upon the relationship of the anterior teeth to the NP line; and to the AP line as far as determining the degree of convexity or concavity. The question is whether the amount of crowding can be corrected while still maintaining a favorable relationship to NP. Another factor is the FMA. In a low angle case, with an FMA below 16°, I am leary of extracting in both arches, unless there is a severe amount of crowding. In addition, clinical intuition plays a part. I may swing back and forth on borderline cases. Treatment mechanics also plays a part. I like to think of the difference between a Class I and a Class II as the mesiodistal width of a bicuspid divided between the two arches. If you move the lower arch anteriorly one-half of a bicuspid width and move the upper arch distally to the same extent, each of which is about three or four millimeters, you have changed a Class II to a Class I. If this is feasible considering crowding and facial fullness, the case can be treated nonextraction. In addition to all these, the inclination of the upper molars may be a factor. Quite often, mesially inclined upper molars can be corrected to a Class I much more readily than those which are upright or distally inclined. The anchor bends in the Begg technique are intended to upright a mesially inclined molar; but not to tip an upright molar distally. If it does that, there has been too much anchor bend and the mechanics are wrong. Here is a case that demonstrates some of these points. It was a Class II with mesially inclined upper molars. There was very little crowding in the lower arch; almost 10mm of protrusion, with spacing, in the upper arch. The labial surface of lower incisor was on the NP line and there was a welldeveloped pogonion. FMA was a relatively low 27°. So, this case had a number of factors that marked it as a nonextraction case in my book. My first objective was to open the bite and to upright the mesially inclined upper molars. I put in some strong anchor bends on the molars and used very light Class II elastics. Most of the time, on nonextraction cases, I do not band bicuspids. I usually just band the molars and the six upper and lower anteriors. Occasionally, I may need bicuspid bands later in treatment. I got the bite opened and the molars went from a Class II to a Class I in four months. His entire active treatment took less than sixteen months. I did not use an upper retainer on this case. On the lower, I used a 3-3. I don't really think that if you have an FMIA under 65° that you have ruined the face. This patient had a pretty good face with an FMIA of 55°. I think it is the position of the incisal edge relative to the NP and AP lines that is important: Here the lower incisor was right on the NP line and less than 2mm in front of AP line. 88

His upper right central and lateral teeth had been injured prior to treatment and I did a lot of grinding on those teeth to eliminate the fractures. Here is another nonextraction case. It was a Class I with a six to eight millimeter overjet at the incisal level. There was not as favorable a relationship of lower incisor to NP and AP. However, there was no crowding in the lower arch and the FMA was 23°. There were enough favorable factors in this case to throw the balance to nonextraction. Once again, I banded just the six upper and lower anterior teeth and the four first molars. I placed strong anchor bends in the archwires and used very light Class II elastics. This boy had practically no retention on his upper teeth. As a rule, I tend to minimize upper retention on nonextraction cases. I play them by eye. I may let them go for six weeks and, if it is obvious that spaces are getting larger or I am losing some vertical, then I will put in an upper Hawley with a bite platform. In this case, I may have used an upper Hawley with a labial elastic for the first couple of months. On the lower, I used a 3-3. He wore a rubber band from cuspid bracket to cuspid bracket for about six months to gather the lower incisors and to upright them a bit. I use a rubber band in this way on most cases. Its position is dictated by need. For example, when appliances are removed, the lower incisor edges may be a little flared. In that case, the lingual bar of the 3-3 is placed low and the rubber band on the labial is placed a couple of millimeters above that. This gives a little torquing action and you can improve that axial inclination a little. When I am through with the labial elastic action, I grind the brackets off the cuspid bands and continue the 3-3 retainer. We got some good growth in this case and a good face. The FMIA was 63° in this case and the relationship of incisal edge to NP and AP improved a bit. We started out with a good chin and that grew a bit more. Incidentally, notice that the contact of the upper centrals initially was high up at the gingival. I am more and more uprighting roots distally on centrals such as this, using uprighting springs to move the contact farther incisally as I did here. Also, I do a fair amount of contouring as on the cuspids here. Just artistic shaping of the teeth. This next case is a Class II division 2, with the upper incisors biting the lower gingiva. With such a big pogonion, with lower incisor so far behind the NP line, with such a low FMA, this is definitely a nonextraction case. As for most of these people, I banded the upper and lower molars and the six upper anterior teeth only, because the bite would chew up the lower anterior brackets. I did not place lower anterior bands. Instead, I had a lower lingual arch. I put severe anchor bends in the upper archwire and used 3-4 ounce Class II elastics. The object is to get the anterior teeth away from each other. If I can get the upper anteriors labially, I can then place the lower anterior bands behind them. I used the vertical loops to assist engagement and to obtain action on all the teeth at once. Usually, I make it a point to avoid loops in nonextraction cases where there is a severe amount of crowding, because the cuspids cannot go distally and you are liable to displace an incisor through the labial plate, especially in the lower arch. Under those circumstances one might consider one lower anterior extraction. If I have just one rotated lateral, I would make a plain arch with no vertical loops, but oversized with the elastic loops up against the cuspid brackets. I may tie the lateral with ligature a couple of times before engagement with a pin. It is a 89

matter of time and expediency. It is not that critical that you get that tooth rotated perfectly before you start your retraction. It doesn't affect your overall treatment if that tooth is not completely rotated in the first two or three months. You can go ahead and open the bite and start retracting, and you can be rotating all during this time. If three or four of the six anteriors were rotated and one or two badly so, I would start with vertical loops in the archwire. Appliances were removed after 23 months of treatment. This boy started out with an upper Hawley, which he lost almost immediately, and a lower 3-3 with an elastic from cuspid bracket to cuspid bracket to upright the incisors. When patients lose the upper retainer, I often leave it out for a while to see what will happen. I did in this case and never did replace it. The post-treatment photo and ceph show improvement in the face with a good amount of vertical growth and an increased chin growth. Here is a textbook Class II division 2 with the laterals out, centrals in, and upper bicuspids tending to crossbite. With an FMA of 24°, with lower incisor behind the NP line, and especially with lower incisor so far behind the AP line, I felt that extraction would not be conducive to facial improvement. If I ever extract in the lower arch in division 2's, I start out using heavy Class II forces and burning anchorage. The object of lower extraction would be to permit alignment of the lower teeth. Although the lower teeth were irregular in this case, the amount was not sufficient to counterbalance the factors which favor nonextraction. The amount was sufficient, however, to permit banding of the lower anterior teeth from the start of treatment in this case. Once again, the purpose of the vertical loops is to secure engagement and to get the action going on all the teeth at once, but I get out of loops as quickly as possible. Here we are about one year into treatment. Notice the offset bends in front of the molar tubes to clear the bite, and notice that I do not repeat them anteriorly. The little offset in the lower anterior region was to adjust for the height of one incisor which was fractured. Notice, also, that I am getting a little tipping. With a lot of Class II forces in a nonextraction case with this setup, the molars tend to tip, with the apices beginning to come anteriorly and the crowns to roll distolingually. Now, on this type of case or on any case with a deep bite, where I know I'm going to have a lot of strain on the molars, I will use a lower lingual arch. In any event, on all nonextraction cases, I put lingual tubes on the molars rather than lingual buttons, with the idea that they are there if I have to go to a lingual arch. Well, we got some lingual tipping in this case in spite of the fact that I had a lower lingual arch in place with a tab extending back onto the lingual of the second molar to help control. Here is the case two years later and, once again, upper retention was for a very short period of time, because the patient lost his retainer within three months. The usual lower 3-3 retainer was used. The lower left first bicuspid wanted to come buccally, and I think perhaps I should have used a lower 4-4 retainer instead of the 3-3. In cases in which you have brought the lower anterior teeth forward due to facial requirements, I think they tend to go distally at the expense of displacing a bicuspid either to the buccal or the lingual. We got a phenomenal amount of growth in this case. This is another example that FMIA cannot be the ruling criterion in cases like this. FMIA was 71° before treatment and 53° after treatment. The criterion of this satisfactory facial result is the relationship to the NP and AP line, plus the good torquing action on the upper incisors. We have looked at four nonextraction cases— a Class I, a Class II division 1, and two Class II division 2's. Now, let's compare nonextraction and its criteria with a typical four-bicuspid extraction case in my practice.

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This was a high angle case with an FMA of 38°. There was crowding of the lower anterior teeth which were already well forward of the AP line and twice as far forward of the NP line. Chin development was poor and the face was protrusive. We went through a typical treatment, and here is the case in early retention . Notice that the lower molar is cocked a little bit. I think that if you start grinding on something like that, it is wrong. This will settle in real well. I used a wire retainer on the upper teeth in this case, because the lateral had been too rotated to retain with an elastic. About one year later, see how those molars have settled in. And, here is the case one year later, in post-retention. The face is improved. There has been a good deal of forward growth of the mandible, but not much chin development. The relationship to NP and AP lines is improved. One additional reason for showing this case is that some people tend to knock the Begg technique on mandibular rotation and angle opening. Well, I think that the angle FMA actually closed two or three degrees during treatment.

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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Jun(391 - 395): Palatal Root Torque of Maxillary Cuspids Utilizing the Begg Technique --------------------------------

Palatal Root Torque of Maxillary Cuspids Utilizing the Begg Technique HARRY MASSIER, DDS Occasionally, the orthodontist finds the apex of a maxillary canine root has been repositioned labially unintentionally, to the extent that the root is palpable (Fig. 1). This may result from a combination of intrusive and distal tipping forces as utilized in Begg mechanotherapy. Etiology Canine intrusion may result in an unfavorable root position under certain conditions: 1. The more vertical and upright the tooth is in its original position, the greater the chance for the root to be displaced labially. 2. Compressed archwires tend to move the crown lingually and the apex labially. 3. When Class II elastics are attached from the lingual of the mandibular molars to the labial of the canine, this may initiate lingual crown and labial root position .

When cuspids are being tipped distally with the aid of Class II elastics, they should be guided into a wider part of the arch. Without compensatory expansion in the archwire, cuspid crowns move palatally and their apices might tend to tip labially. Corrective Treatment In instances of pronounced labial movement of the canine apices, the patient may or may not indicate pain symptoms. If there are signs of positive pain, immediate measures should be instituted to lingualize the involved root. A recommended procedure is to pin an .018 wire, which has two mushroom-like spurs at the cuspid level, as designed by Sims1 (Fig. 2). These spurs have the double purpose of repositioning the canine roots palatally and for the purchase of elastics. The archwire is compressed in the molar region to avoid flaring of the buccal segments. Anchor and V-bends are omitted. If Stage III mechanotherapy is required and the cuspid root apices are unfavorably labial, and there are no symptoms of pain, specialized procedures are required to prevent complicating reactions and to correct the cuspid roots. In these instances, uprighting the roots may be a difficult task. The apices have to be brought through the dense cortical plate, which may cause resorption2,3. The paralleling will be at a slower rate than through cancellous bone. Anchorage 92

preservation may be critical. The objective is not to bring the crown mesial in order to upright the root. The following case report will illustrate the specialized procedures. Specialized Procedures A female, aged 16, presented with a Class II division 2 malocclusion (Fig. 3). There was a deep anterior overbite and an unfavorable inclination of the canine roots. The four first bicuspids were removed and the malocclusion was treated with Begg mechanotherapy. During Stage I and Stage II, the Class II elastic traction was directed from the lingual of the mandibular molars to the circles on the cuspids. At the beginning of Stage III (Fig. 4), the canine crowns were lingually inclined and their roots excessively labial and palpable. It was obvious that insufficient expansion had been included in the maxillary archwire, resulting in this complication. The x-ray (Fig. 5) of the left cuspid clarifies the axial inclination. A thin cortical plate surrounds the root apex. A two-spur torquing sectional (Fig. 6) was placed to reposition the roots of the maxillary central incisors lingually, and a root paralleling spring was inserted on the cuspid. After 2½ months (Fig. 7), the degree of root uprighting of the canine was questionable. This could be detected by examining the gingival band level of the lateral and cuspid, and comparing this with previous photographs. A decision was then made to seat a 4-spur torquing sectional auxiliary (.014) with spurs on both maxillary central incisors and cuspids. Four months later (Fig. 8), torquing of the cuspid root showed considerable progress. This can clearly be seen from the change in the position of the spur which was on the labial bulge of the crown (Fig. 7) and is considerably over to the mesial (Fig. 8). Also note the change in the heights of the gingival borders of the laterals and cuspids. At this point, the uprighting was well under control, making proper progress, and the root apices were no longer palpable. Therefore, the cuspid torquing spurs were snipped off and the remaining portion of the auxiliary continued to function in order to further reposition the roots of the central incisors lingually. Figure 9 shows the teeth after debanding. The 4-Spur Torquing Auxiliary The basic form of the 4-spur torquing auxiliary (Fig. 10) does not differ radically from the 2-spur sectional. 1. It should have more constriction to counteract flaring of the buccal segments. It is also longer and pinned to the second bicuspid brackets. The base wire (.020) should be constricted in the molar area, and have toe-in and step-up (V) bends. 2. The cuspid spurs should be constructed at an angle, so that after being pinned, the spurs lie across the center of the cuspid crown and not to the distal, as this would inhibit uprighting. This requires a longer spur, bent at a crisper angle. 3. The adjustment on the cuspids is stronger than on the central incisors, since the action on the anterior teeth would diminish the effects posteriorly. 4. It is expedient to bend the distal spur legs slightly inward prior to seating the torquing auxiliary (Fig. 11). Failure to do so will result in breakage and distortion, and interfere with the insertion of root-paralleling springs. 5. Since the shape of this torquing sectional and its base wire closely resemble the form and contour of the 2-spur sectional and its base wire, there is no contraindication to cut off the cuspid spurs when they are no longer required. The anterior spurs can continue their root repositioning. 93

Conclusion This paper described a specialized adaptation of the Begg Technique mechanotherapy to correct the complications of labially malposed cuspid root apices. These applications of Begg principles are another indication of the versatility of this fixed appliance, and its ability to control crown and root movements. The author wishes to thank Dr. Sidney Brandt, Morristown, N.J. for rewriting this paper for this publication.

Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Jun(391 - 395): Palatal Root Torque of Maxillary Cuspids Utilizing the Begg Technique. -------------------------------. Sims, M. Advanced Begg Course, University of Groningen, August 1972. 2. Ten Hoeve, A. and Mulie, R.M., The Effect of Antero-Postero Incisor Repositioning on the Palatal Cortex as Studied with Laminagraphy, J. Clin. Orth. Nov. 1976. 3. Ten Hoeve, A. and Mulie, R.M., The Limitations of Tooth Movements Within the Symphysis, studied with Laminagraphy and Standardized Occlusal Films, J. Clin. Ortho, Dec. 1976.

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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Sep(610 - 613): Second Premolar Extraction in Begg Technique --------------------------------

Second Premolar Extraction in Begg Technique F. G. THOMPSON, DDS After a few years of experience with Begg technique, I found it was possible to control anchorage well in the average case, but there were a number of cases in which it was being too well controlled and excessive lingual movement of the denture was being produced. In many cases, I was producing the very thing which I had set out to correct— an undesirable facial profile. There were two types of situations in which this problem seemed to arise. First, the mild Class II case with low MPA and no crowding. It rapidly became apparent that extraction of four first premolars and Begg treatment was not the treatment of choice for this type of case, and that this was much better handled on a nonextraction basis with headgear if necessary. The other type of case in which over-retraction occurred was the skeletal Class I or mild Class II in which there was a slight degree of crowding and a good profile. Challenge of the Borderline Case Employment of the differential force principle, using much heavier elastics in this type of case, in an effort to bring molars farther mesially, was a help; but the true borderline case, with good facial profile and mild degree of crowding still remained a challenge. If it was treated nonextraction, there was inevitably some relapse of crowding, and if first premolars were extracted, one risked spoiling the profile. In 1965, Henry2 gave two basic criteria for extraction of second bicuspids: 1. A mild degree of crowding and a good profile. 2. No crowding and a fullness of the lips. Although Begg3 stated that second premolars should not be extracted instead of first premolars unless they are carious or poorly formed, I could see no reason why Henry's criteria could not be applied to Begg technique. The logic seemed unquestionable. Instead of pitting the six anterior teeth against the second premolars and molars, the anteriors plus the first premolars were now being pitted against the molars. Most important of all, facial contours remained soft and full throughout treatment. Accordingly, I began to be interested in second premolar extractions.

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Nance4 was one of the first to draw attention to the alternative of extracting second premolars in mild discrepancy cases— the sort of case in which we wish we might extract a part of a tooth rather than a whole tooth. He stated that this avoided a dished-in face and that there was less tendency for residual spacing to occur. Carey5 advised second premolar extractions in cases with a discrepancy greater than 2.5mm, but less than 5mm. Dewel1 observed that in the borderline case, extraction creates more space than is necessary and this must be closed by mesial movement of posterior teeth. Extraction of second premolars facilitates this by reducing the anchorage value of the buccal segments. Shoppe6 observed, "More mesial movement of molars (maintaining good inclinations) may be accomplished through second bicuspid extraction". Schwab7 found that both upper and lower incisors were retracted less in relation to skeletal landmarks when four second premolars were removed. Logan8 noted similar findings and listed other factors of significance when second premolars were extracted: the maxillary first premolar is more esthetic than the second; the contact point of mandibular first molar and first premolar tended to stay closed; rapid space closure reduces the possibility of buccal or lingual bone furrows in the extraction site; overbite can be controlled as easily or more easily with second premolar extractions; closure of anterior open bites is facilitated by reducing posterior vertical dimension; the mandibular first premolar is shaped better to retain a band than a second premolar. De Castro9 considers the mammalian dentition as an arrangement of three independent segments— an anterior segment ending at the canines and two posterior segments. When a second premolar is extracted in the middle of the posterior segment, only this segment is shortened. However, when first premolars are extracted, both the posterior segments and the transitional areas are disturbed, with a greater effect on the functional integrity of the dentition. He makes the further observation that " In most techniques, the chief emphasis is placed on maximum cases. However, when the general rule for maximum cases is followed in all extraction cases, a high percentage of unsatisfactory esthetic results occurs. Excessive retrusion of maxillary and mandibular incisors results in an appearance as poor as the excessive labial protraction that existed before treatment. In maximum cases, the results are satisfactory, but in many of the average cases, the patient would have been better off without treatment". Modifications in Begg Technique For Second Premolar Extraction We have stated Henry's criteria for second premolar extraction as mild crowding with excellent profile; or no crowding with slight lip fullness, requiring minimal retraction; or combinations of these. Another possibility is the mild Class II division 1 case in which slight crowding in the mandibular arch precludes nonextraction treatment, and where minimal torque of upper incisors will be required. Still another category is the mild Class III case in which maxillary crowding necessitates extraction, yet retraction of maxillary incisors is undesirable. Occasionally, a combination of second premolar extraction in one arch with first premolar extraction in the opposing arch may be the combination of choice. In the good profile/mild crowding type of case, little if any change in either labiolingual or axial inclination of anterior teeth is required. There is, therefore, nothing to be gained by allowing the anterior teeth to tip back to an excessive degree, only to have to bring them back again to their original positions— the so-called "round trip". Instead, the anterior teeth are brought into bracket engagement and bayonet bends are placed where necessary (Fig. 1). Free tipping is not necessarily desirable, so the teeth are frequently pinned more firmly than usual. The first bicuspids are also banded early in treatment and pinned to the archwire to maintain them at the correct level. As soon as the end of Stage I is reached— namely, bite opened, overcorrection of irregularities, incisors edge to edge— the normal technique is varied (Fig. 2). It is desired to maintain the labial segments as they are at that point, so uprighting of canines and first premolars is commenced immediately and reciprocated by intramaxillary traction to bring about mesial movement of the molars. In other words, Stage II and Stage III are carried out simultaneously. Heavier archwires are placed in both arches, .020 upper and .018 lower, with bayonet bends as required. The arches are engaged in all brackets and any required molar offsets are placed. Sufficient anchorage bends are placed to maintain the 96

molars upright as they are being moved mesially. Care must be taken to place offsets and anchorage bends sufficiently far from the buccal tubes to allow complete space closure without needing to remove the archwire. Uprighting springs are placed on first premolars, canines and lateral incisors as required. Occasionally, torque is required or sometimes a reciprocal torquing auxiliary is used to bring lateral incisor roots labially. The mesial component of force on the crowns of the canines and premolars from the uprighting springs is reciprocated by intramaxillary elastics, usually 3-4 ounces, in order to move the molars mesially and counteract the effect of two or three uprighting springs all working in the opposite direction (Fig. 3). In addition, lingual elastics ties are frequently used from lingual hook on molar to eyelet on canine to control rotations or buccal rolling of molars. Flat oval tubes are rarely used, unless molars are badly tipped at the start of treatment, as control can be satisfactorily achieved by a combination of buccal and/or lingual elastic traction and heavier archwires. In many cases, very little change or alteration of appliances is required from this stage until the completion of treatment. Frequently, the overall treatment time is reduced, as those things normally done during Stage II and Stage III are done simultaneously. The average treatment time for twelve cases selected at random was twelve months, with a range from nine to seventeen months. Occasionally, a Stage IV archwire may be required to upright molars, if insufficient anchorage bend has been placed; or to finish the detailed alignment. However, the previous stages have usually been completed relatively more quickly, so that there is no problem economically about a further arch change. Summary The indications for second premolar extraction are: • Good profile plus mild crowding. • Flat profile plus moderate crowding. • Class II division 1 arch relation on Skeletal I base with mild mandibular crowding . • Mild Class III arch relationship with mild crowding in maxillary arch. The advantages of the approach shown are: • Original facial contours can be maintained, without reduction of lip profile. • Maxillary first premolar is frequently a more esthetic tooth alongside a canine. • There is frequently less tendency for extraction spaces to reopen in the mandibular arch. • Less possibility of buccal or lingual bone furrows in the extraction area, because of rapid space closure. • The "round trip" is avoided. In the words of Shoppe6, "There are many who have reported with pride, and justly so, the great distances that incisor teeth can be moved lingually. However, diagnosis and treatment procedures to retain lower incisor teeth in precisely their original positions and inclinations, seem to provide an equal challenge" and a comparable degree of satisfaction.

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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1977 Sep(610 - 613): Second Premolar Extraction in Begg Technique. -------------------------------1. Dewel, B. F.: Second Premolar Extraction in Orthodontics; Principles, Procedures and Case Analysis; A.J.O. 41 107-120 Feb., 1955. 2. Henry, R. G.: The Extraction of Four Second Premolars in Orthodontic Treatment; Aust. Orth. J. 1 28-32 Oct., 1967. 3. Begg P. R. & Kesling P.: Begg Orthodontic Theory and Technique. W. B. Saunders Co. 1971. 4. Nance, Hays N.: Removal of Second Premolars in Orthodontic Treatment. A.J.O. 35 685-696 Sept., 1949 5. Carey, C. W.: Diagnosis and Case Analysis in Orthodontics; A.J.O. 38 149-161, March, 1952. 6. Shoppe, R. J.: An Analysis of Second Premolar Extraction Procedures; Angle Orth. 34 292-301 October, 1964. 7. Schwab, D. T.: The Borderline Patient and Tooth Removal. A.J.O. 59 126-145, February, 1971. 8. Logan L. R.: Second Premolar Extraction in Cl. l and Cl. ll. A.J.O. 63 115-147 February, 1973. 9. De Castro, N.: Second Premolar Extraction in Clinical Practice. A.J.O. 65 115-137, February, 1974.

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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1974 May(286 - 293): Concept and Commentary: One-Arch Extraction Cases --------------------------------

commentary concept ONE-ARCH EXTRACTION CASES Joe A. Sain, DDS This next group of cases are one-arch extraction cases. I know that some orthodontists tell you they never extract one arch. Well, somewhere along the line, someone is going to show up who has lost a tooth due to decay or who has a tooth congenitally missing. So, you don't necessarily have to prescribe extractions to have a one-arch case, even if an orthodontist has some prejudice against this type of case. Most often they say they don't like the occlusion with two bicuspids gone, but if you grind properly to adjust the teeth, you can create an acceptable interdigitation. The first molar teeth don't know that they are occluding Class II and the esthetics is very good. You don't get the best occlusion of the second molars, but that doesn't negate the rationale of one-arch extraction. One clue about nonextraction and one arch extraction is that, many times, looking at your models from the buccal in the molar area, the molars will be rotated enough so that you will think it is a full Class II. But, if you look at it from the lingual, the mesiolingual cusp is occluding in the central fossa of the lower molar and with just a little buccal rotation you can easily create a Class I relationship. If the lingual cusp is forward of the central fossa, then you have a different story. If you create a full Class II out of that, you have to adjust the height of the lingual cusps of the upper molars because these teeth will be occluding first on the mesial marginal ridge of the lower molars. Let me show you a few one arch extraction cases and see how it worked out. Case 1 Here is a Class II case with a cusp-to-cusp posterior relationship and a regular lower arch with slight spacing. 99

As far as the measurements and other considerations were concerned, she had an acceptable face to begin with. A moderate Class II with a little roll of the lower lip. I extracted the two upper first bicuspids and banded all the upper teeth. In the lower I had my usual nonextraction strapup with bands on the lower first molars and the six anteriors. I used light Class II elastics while I was rounding out the upper anterior section to prevent these teeth from moving forward. After that I used only intramaxillary elastics in the upper arch. I could afford to do this because I had anchorage to expend. Notice that when I had sufficient bite opening, I went to a lower arch with a step down bend in front of the molar that was not repeated distal to the cuspid. Also note that the anchor bend was flattened out in Stage III of treatment; note the short-arm uprighting springs so that the arms do not cross; and note the reverse torquing auxiliary on the upper laterals. Case 1 treatment sequence The case was retained for a minimal time and here it is out of retention. This case may demonstrate one reason why some people may be negative about one-arch extraction. The molar should have been uprighted more or the lingual cusp needs to be ground. You'd get better interdigitation. Case 2 Here is a deep bite Class II case with no crowding in either arch. The decision not to extract in her lower arch was predicated on her having a well-aligned lower arch and a prominent pogonion. Also, her lower teeth were distal to the NP line. There is no crowding and these teeth are already distal to that profile line. She had something of a mid-face protrusion and I think that this person is still going to grow some more pogonion. To extract in the lower arch under these conditions would be a disaster. It is possible that this case might have been treated nonextraction, but I wanted to minimize any further forward inclination of the lower anterior teeth. I extracted two upper first bicuspids and used intramaxillary and light Class II elastics. I felt that the molars would tolerate that and that I had that much anchorage to expend. Here is the case in late retention. I don't think I could have gotten a better result either nonextraction or by extracting four teeth. Case 3 Here is another of these cases. It was a Class II with a heavy chin, deep bite, a little crowding in the upper but none in the lower. I prefer to get most cases after the mixed dentition stage, unless they have crossbites or Class III or something unusual. Since I have gone into Begg, I prefer to have second molars in the mouth, but I don't necessarily hold up treatment if they are not in. In this case they were present and treatment was carried out similar to the others. I mentioned in the previous case that I took the molar bend out in Stage III. This was not done in this case and it was an error. Notice the molar bend still in. I used to do this in Stage III and got this distal tipping in every case. It finally dawned on me that I should flatten out the anchor bend at the beginning of Stage III or even put a little reverse curve in front of the molars, and come forward and put my V-bend between the cuspid and second bicuspid on first bicuspid extraction cases. Here is the case a year or so after treatment. Looking at the face, just imagine what he'd have looked like if I had taken out lower teeth. 100

He grew chin. He grew nose. He would have looked edentulous. He is an exaggerated example of when and why I extract only in one arch. I think, though, that we might have had quite a bit of crowding in the lower if we had used Class II forces. Case 4 Here is another case with most of the things we were talking about. This was a Class II case with crowding and irregularity in the upper anterior section, but with a good lower arch. The cephalometric x-ray showed that the lower anteriors are in a good relationship to the AP line. They should not be moved forward with Class II mechanics in nonextraction treatment, nor moved back in an extraction treatment. The face is upright and should be made neither flatter nor more protrusive. A lot of these cases treat in ten to fourteen months. However, I am not a fanatic on shortness of treatment. I think a lot of people may have gone into Begg with the idea it would shorten treatment, and frequently it was shortened too much. In this case, active treatment took eleven months. I would accept this result in my mouth or in my child's mouth. No lower retention was used. The point here is, if you have a Class II case with not much overbite and a good lower arch, extracting two upper bicuspids and using horizontal elastics on the upper is frequently the method of choice. Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1969 Feb(67 - 81): Non-extraction Treatment with the Begg Technique - BRAINERD F. SWAIN, D --------------------------------

BEGG SERIES PART VI Non-extraction Treatment with the Begg Technique BRAINERD F. SWAIN, DDS In describing his treatment of the four non-extraction cases presented in his text, Begg1 noted that (1) no third stage mechanics were required for two; (2) the third patient needed no second stage, and the third stage was limited to distal root tipping of one lateral incisor; (3) the fourth patient required only single arch treatment of the upper jaw, and no stages as such were used at all. Similar observations could be made for Begg non-extraction treatment categorically, and this in turn leads to a generalization. Non-extraction cases are not treated like extraction cases: some but not all of the characteristic mechanics are used in non-extraction treatment because some but not all of the characteristic tooth movements are required. In extraction treatment, for example, second stage mechanics are used for closure of the extraction spaces, and third stage mechanics must include re-paralleling of the roots of teeth on either side of the extraction site. However, in non-extraction cases, little or no spacing may exist at any time in the buccal segments, consequently second stage mechanics and third stage paralleling are required briefly or not at all. There is a second distinction between extraction and non-extraction treatment, and it is this: good dento-facial growth and harmony between tooth size and arch length should be the rule, with but rare exceptions. This means that the malocclusions of patients undergoing non-extraction treatment should be relatively mild; the number of teeth in malposition should be fewer; and the amount of time and space required for correction of individual malpositions should 101

be proportionately less. The lower teeth should be in good alinement, with or without spacing. In some cases, there may be mild crowding of the lower incisors, provided they are in lingual axial inclination. Forward tipping places these teeth in an upright position and simultaneously provides sufficient arch length to permit alinement. This can be done rapidly and with little tax on anchorage. Reduction in the anchorage-taxing force of wires and elastics is important to non-extraction treatment by any technique because, although non-extraction cases are seldom described as such, they are, nonetheless, maximum anchorage cases where little or no forward movement of the anchor molars would be desirable, just as in extraction treatment of severe discrepancy cases. In correction of these mild nondiscrepant occlusions with the Begg technique, the hazard of forward movement of the anchor molars is reduced because, of the forces which might result in such movement, both the magnitude and the elapsed time in which they need to be exerted are less. For example, Class II elastic force seldom exceeds 1 1A2 to 21/) ozs. Second stage horizontal elastic force, as noted, is used briefly or not at all. In the third stage, the amount of force and the time required for torquing are both reduced since the upper incisors usually require less uprighting because there are fewer and smaller spaces to be closed during the first two stages. In addition, it is not infrequent that torque is limited to root tipping of the upper central incisors. Molar tipping enhances anchorage One of the paradoxical but pleasant surprises of Begg nonextraction mechanics is that anchorage potential is often enhanced if the anchor molars have a mesial axial inclination at commencement of treatment. This comes about through proper manipulation of force, resistance and time and may be described as follows: 1. The anchorage bend and Class II elastic forces exerted on the anchor molars and the anterior teeth in the first stage are equal and opposite, but the resistance encountered by these forces is not. Bodily forward movement of the anchor molars occurs in reaction to the arch wire and elastic traction forces, but this is root movement, which is a highresistance, slow-response type of movement. On the other hand, the anterior tooth movements, which typically include crown tipping and rotation during alinement and retraction, together with depression during overbite correction, are all low-resistance,rapid-response movements. Therefore, if the anchor molars exhibit a mesial inclination at commencement of treatment, the combination of normal anchorage bend force with slightly subnormal Class II elastic force usually employed in nonextraction treatment brings about a beneficial distal tipping of the molar crowns into an upright position. In addition, and provided that the Class II elastic force is sufficiently light, the lower as well as the upper molar crowns actually tend to move distally. This net distal movement occurs because, although the influence of the anchorage bend simultaneously tends to tip the crown back and the root forward, the resistance to crown tipping is low while the resistance to root tipping is high. Consequently, crown tipping responds rapidly and root tipping slowly. Such net distal movement of mesially inclined anchor molars can be important in non-extraction treatment because it provides more arch length for teeth anterior to these molars. 2. Although the uprighting of anchor molars is always beneficial, net distal movement of these teeth resulting in an increase in arch length is not so important in extraction cases because elastic forces are often higher and used longer, and the concomitant forward movement of anchor molars is normally desirable. 3. However, net distal movement of mesially inclined molars resulting in an increase in arch length is effective in nonextraction treatment because, as previously noted, elastic forces are lower and used for shorter periods of time, thus reducing any subsequent tendency for the molars to move forward. Of course, mesially inclined molars are not present in all nonextraction cases, just as the other criteria required for nonextraction treatment are only found in a minority of all cases. However, the simple test shown in Fig. 1 has been found useful. If the distal cusps touch the base but the mesial cusps do not, and provided the other requirements for nonextraction treatment are present, the prognosis for a good result is proportionately enhanced. 102

4. Net distal movement of mesially inclined molars is effective in correction of Class II malocclusions. This also is due to the proper manipulation of force, resistance, and time, especially time. Class II elastic force is usually required for a longer time in Class II cases in order to attain an edge-to-edge relationship of the anteriors and Class I occlusion in the buccal segments. The influence of this additional time on these forces and the resistances they encounter may be described as follows: The upper molar crowns undergo net distal movement until the teeth are upright and, because of the additional time during which anchorage bend force is exerted they often tip distally. This is one increment of change from Class II to Class I molar interdigitation. The lower molar crowns seldom undergo net distal movement. Although, initially there is a tendency for the crowns to tip distally more rapidly than the roots to move mesially, the continuing Class II elastic force not only inhibits distal crowntipping but the added time made available for mesial root tipping permits more of this slow-response movement to occur. This is another increment of change from Class II to Class I molar interdigitation. When these two differential movements are attempted on Class II patients who exhibit good dentofacial growth, and harmony between tooth size and arch length, the resulting Class I occlusion and its post-treatment stability are both good. Distally tipped upper molars in these cases routinely become upright after appliance removal but without loss of the Class I relationship. Similarly, lower molars seldom move too far forward as a result of the additional time in which the Class II elastic force is exerted. Not infrequently, the correction of Class II occlusion occurs quite rapidly, for example, in six or eight weeks. Since little distal crown tipping of upper molars or mesial movement of lower molars is apparent, it is difficult to explain the Class I occlusion on the basis of tooth movement alone. Furthermore, this is a rather brief time period to permit an explanation on the basis of growth. It is not too brief however for the substantial and rapid reduction in overbite and overjet that consistently accompanies these rapid Class II corrections. Herein may lie an explanation. The prompt reduction and elimination of overbite and overjet with Begg mechanics could permit a prompt forward relocation of the mandible to occur if there were any potential for it to do so. Conversely, if the upper and lower anterior teeth are in some degree of overbite and overjet contact when in centric occlusion, then no forward relocation of the lower jaw can occur without an improved relationship of these two, and one cannot know if the potential for such movement exists. This is merely a speculation; it is recognized that mandibular relocation is controversial. However, correction of the Class II occlusion in combination with correction (and pro tempore elimination) of overbite and overjet frequently occurs so rapidly that an explanation based on growth or tooth movement alone seems less plausible. It seems more tenable that varying increments of growth, tooth movement and relocation may all be involved. It was noted that treatment of non-extraction cases usually requires some but not all of the characteristic tooth movements needed for extraction cases, and, consequently, some but not all of the characteristic mechanics are used. In the discussion of nonextraction treatment, the emphasis will be placed on the exceptions and modifications in mechanics. This of course implies a treatment norm from which such variations have been made, and the reader is referred to Dr. Begg's text for his discussion of the basic objectives, tooth movements, wires and elastic forces, and the timing of the three stages of treatment. Unless noted otherwise, these procedures and recommendations coincide with the treatment described herein. Constructing the appliance In constructing the appliance, the author prefers to band all teeth except the second molars, unless, of course, they are in need of correction. Occasionally the bicuspids are not banded, but it is always helpful to be able to engage these teeth on the arch wire during the third stage to aid in obtaining precise alinement, proper arch form and width, and a flat occlusal plane.

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Although the bicuspid may or may not be banded, it should not be attached to the arch wire during the first stage, and this stricture, of course, applies to extraction treatment as well. However, in non-extraction treatment, maximum anchorage conservation is vital and the bicuspids must not interfere with the free interchange of anchorage bend and elastic force, thereby delaying rapid completion of the first stage movements, particularly overbite correction. This does not preclude the use of ligatures or clamps to guard against excessive deflection of the arch wire resulting in distortion since these devices help maintain the free interchange of forces. However, they should only be employed as guardianmaintenance devices and should not be in sufficiently tight contact as to either detract from or contribute to the force in the arch wire, for both overbite and overjet correction are more efficient if obtained as the direct result of the anchorage bend and elastic forces exerted on the molars. It is customary to make the initial arch wire somewhat wider than the dental arch in both the cuspid and the molars regions. This may be called expansion-for-prevention because it is used to prevent lingual tipping of the molars, particularly the lowers, during the first stage. The amount of expansion placed in the arch wire is less than that required for extraction cases. As a general rule, approximately 2 mm expansion at each cuspid and 6 mm at each anchor molar is a satisfactory adjustment when first inserting the arch wire but this should be modified as indicated if the anchor molars contract, or, less likely, expand subsequently. Looped arches are used where necessary, but should be discarded for plain arches as promptly as possible. This is important because in nonextraction treatment, the total arch length at commencement of treatment is often greater than in extraction cases, but, in any event, will remain lengthy throughout treatment. Consequently, deviations in arch form and symmetry, and unevenness in the occlusal plane of the anterior teeth, resulting in a delay in correction of overbite and overjet, can occur because the anchor molars which control these things are further away from the anterior teeth. Since a plain arch wire has less flexibility in both the horizontal and vertical planes, it is much more efficient for maintaining form and symmetry and for leveling the anterior teeth during overbite correction. As noted previously, there may be little or no spacing in the buccal segments of a non-extraction case, and on occasion there may be a tendency for the bicuspids to be displaced during the first stage, particularly in the lower jaw. This can be prevented by placing an adjustable stop at the mesial of the molar tube, but it is essential to recognize that if extended use of such devices is required in order to prevent lingual, occlusal or gingival buckling of bicuspids, then arch length can only be maintained by concomitant forward movement of the anterior teeth. If these anteriors were in lingual inclination at commencement of treatment, such forward movement may be justifiable. However, if they were upright initially, then forward movement is not justifiable and extraction treatment, with the characteristic mechanics used to prevent such forward movement, should be employed. Although less arch wire expansion-for-prevention is used in non-extraction cases, the angle at the vertex of the anchorage bend need not be reduced appreciably. Anchorage bend force is a leverage type force, and since the arch length of non-extraction cases is characteristically greater, the force delivered by a given anchorage bend is decreased in keeping with physical laws that with a given input of force (in this case the anchorage bend) the output is reduced as the length of the lever arm is increased. Actual measurement does not show a significant difference in the force exerted on the anteriors when the same degree or anchorage bend is used for both extraction and non-extraction treatment. In either type of case, however, the proximity of the anchorage bend to the molar tube has a direct bearing on the amount of depressing force exerted on the anterior teeth, for the same anchorage bend will exert considerably more force on these teeth when located at or near the mesial end of the tube and much less when placed at or near the tip of the second bicuspid, for example. This can be used to advantage in nonextraction treatment if the anchorage bend is located only far enough forward to prevent it from entering the tube during space closure. If no spaces are present, it may be placed just in front of the molar tubes. Light elastic force used

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In non-extraction treatment, the same elastics are seldom used. This is true because elastic force is a simple traction force and increases in direct proportion as the distance between the two points of attachment is increased. As noted previously, the arch length in nonextraction cases is often greater, and, in any event, will remain much longer during treatment since there are no extraction spaces to be closed. This means that a given elastic normally would exert more force on a nonextraction case. In most cases this would be undesirable, and lighter elastics exerting l½ to 2½ ozs. Of force as determined by actual measurement are preferable, especially where the anchor molars exhibit a mesial axial inclination at commencement of treatment. When the molars are upright at the beginning of treatment, however, stronger Class II elastic force, approximately 3 to 3½ ozs., occasionally higher, may be used. This is done on a double premise that net distal movement of the lower molar crowns, which would be undesirable since these teeth are already upright, can be avoided through the use of more force. Simultaneously, this higher force frequently accelerates the rapid-response of the low-resistance movements of anterior teeth required in the first stage without appreciably altering the slow-response and high-resistance of the anchor molar to forward movement. The subject of elastic force, chiefly that of the Class II elastics, should not be left without a realistic acknowledgment that anchorage loss will occur with some patients no matter how little force is used. In these instances, extraction treatment should be substituted promptly. Fortunately, after overbite and overjet are corrected in non-extraction treatment, Class II elastics can be entirely eliminated or else used intermittently as necessary to maintain the edge-to-edge relationship of the anteriors. In the third stage, for example, they are employed to help assure that the roots of the upper incisors move lingually and to prevent their crowns from moving labially. However, their aid may only be required on a part time basis, particularly if the torque force is mild or limited to the central incisors only. In such cases the patient should be directed to wear the elastics during each 24 hour period but only for as long as necessary (for example, at night only) to maintain the edge-to-edge relationship of the incisors. After overbite and overjet correction and the other tooth movements of the first stage have been attained, the anchorage bend should be reduced. This is permissible since there may be little or no need for any second stage treatment, and, in the absence of the forward pull of the horizontal elastics of the second stage, the anchor molars might otherwise be tipped distally. Furthermore, the patient is often then ready for the third stage, and it is customary to omit anchorage bends in the arch wires used for this stage. However, if there are spaces in the buccal segments and one or more bicuspids require rotating, elastics or elastic thread may be used. As a rule, bicuspid rotations are usually deferred until the first stage tooth movements have been completed because the tight occlusal interdigitation present at commencement of treatment is then relaxed. Rotations, and even crossbites, are then corrected with little or no occlusal interference. Furthermore, elastic thread or ligatures attached between a bicuspid and the arch wire during the first stage for purposes of rotation will interfere with the free interchange of anchorage bend force between the molars and the anterior teeth and is capable of producing arch form asymmetries. Third stage Third stage mechanics are primarily concerned with torque of the upper incisors, particularly the upper centrals. Unless buccal segment spacing existed at commencement of treatment and was closed by tipping of the tooth crowns during the second stage, there is little need for paralleling of cuspid and bicuspid roots. However, the brief use of paralleling auxiliaries is helpful in precise positioning of individual teeth. It should be recognized that the force exerted by these auxiliaries automatically generates an equal and opposite force which must be dissipated somewhere in the dental arch. Accordingly, it is essential, in non-extraction treatment, that the base arch wire be .020 inches diameter, occasionally .022 inches. When wires of smaller diameter are used, their greater flexibility provides inadequate resistance against the force of the auxiliaries. Consequently, it is not unusual for the reaction of the torque force to cause extrusion of the upper incisors, particularly the upper centrals, and the premature return of overbite. In the case of the paralleling springs, the characteristic reaction is also to extrude the teeth to which they are attached, thus promoting unevenness in 105

the occlusal plane. They also bring about arch form asymmetries. These problems are not exclusive to non-extraction treatment but seem to occur more readily in these cases because of the greater arch length from molar to molar. Furthermore, retrogressive changes in the arch form, symmetry, occlusal plane, or individual tooth positions during the third stage, are more readily apparent in non-extraction cases since, by definition, the malocclusions are milder and both the number and degree of these abnormalities are considerably less. In any event, any changes which could be attributed to the reactionary force created by the resistance offered to torque and paralleling should be avoided by the use of relatively stiff base arch wires which can dissipate this force by distributing it more evenly. Of course, these undesirable changes can be due to faulty adjustments in the arch wires and also are more prone to occur, and at the same time more difficult to prevent if the bicuspids are not banded and cannot be firmly attached to the arch wire in the third stage. In addition, it is important to recognize that the increased stiffness of the heavy base wire is only a relative increase, and compensatory adjustments, particularly the anterior reverse curve in the occlusal plane, are incorporated. In addition to preventing retrogressive movements in the third stage, care and attention should be given to precise positioning of individual teeth, including over-movement or over-correction where indicated. If a number of wire auxiliaries are in use, this can be deferred until the fourth or finishing stage, as is frequently done in extraction treatment, but the reduced number of auxiliaries commonly employed in non-extraction treatment, particularly in the lower jaw, permits concentration on the finishing movements during this stage. Finishing Finishing of non-extraction cases has another side. From an epidemiological point of view, there are more mild malocclusions undergoing treatment each year as lay acceptance of the desirability for straight teeth increases and the distinction between treatable malocclusion and normal occlusion is proportionately narrowed. The problem has to do with relapse following treatment rather than treatment itself. Since some undesirable changes following treatment, or after termination of retention, are the rule rather than the exception, very slight changes in a treated mild occlusion could result in complete relapse because the malpositions were mild and the required correction proportionately slight. Consequently, incomplete tooth movement, including failure to over-correct where indicated, increases this hazard. There is also an ethical principle involved in accepting such mild malocclusions for treatment. This does not mean that one automatically should refuse treatment when signifcant relapse is anticipated, but rather that there should be a full and fair disclosure of this poor prognosis to the patient and parents for their evaluation. Although the justification for orthodontic treatment of many cases can be rationalized anywhere between absolutely imperative and totally contraindicated, such determinations, morally and lawfully, are best made by the patient and parents with the guidance of the orthodontist. While precise positioning of individual teeth within the limitations of the appliance should be done prior to band removal, it is the author's policy to use tooth positioners in most all cases for additional precision in alinement and occlusion. One of the most important attributes in efficient tooth movement during the first two stages is that of the freely-pivoting relationship between the arch wire and bracket so that the anterior teeth can undergo the crown tipping and intrusive movements of these two stages. With the brackets currently used, there is no change in this pivotal relationship with the arch wire during the third stage, and precise positioning of individual teeth, particularly that of roots, is dependent upon the torque and paralleling auxiliaries used in this stage. In most cases, the combination of the arch wires and auxiliaries is capable of producing an adequate result. However, few patients would fail to show additional improvement if a tooth positioner were worn following removal of the fixed appliances. This is especially important in non-extraction treatment where, as has already been noted, the number and degree of malpositions are usually less at commencement of treatment, and any deficiencies in precise positioning of all teeth are much more obvious. Summary of characteristics of non-extraction cases 106

1. The lower anterior teeth are either (a) in good alinement and upright, with or without spacing, or (b) if irregular, they are inclined lingually. Such irregularity is milder, and the lingual inclination is of such degree that when the incisors have been tipped forward to an upright position, there will be sufficient space to permit alinement. In some cases the incisors are irregular but upright; there are no overlapping contacts and there may be spacing. In some of these cases there is a history of tooth injuries during late infancy or early childhood. 2. In a few instances, lower anterior teeth which are in good alinement but exhibit a labial inclination have been treated without extractions. This was done because retraction of such teeth in conjunction with closure of extraction spaces would have been excessive and would have detracted from facial esthetics rather than contributed to an improvement. 3. The dental arches are relatively large and the teeth are of normal size or somewhat small. Although there may be variation in dento-facial growth patterns, the dental arches are of adequate size for all teeth to be in proper alinement and upright over basal bone. 4. The anchor molars of nonextraction cases often show a mesial inclination, which can and should be corrected during treatment. This mesial inclination is easily determined by placing a tongue blade or the flat base of an orthodontic model on the occlusal surfaces of the opposing cast. If the distal cusps of the first molars touch the flat surface but the mesial cusps do not, then this mesial inclination should be corrected by distal crown tipping to an upright position. This molar inclination is quite common in mild malocclusions and is of value because of the light forces and the ensuing tooth movements used in this technic. 5. Most non-extraction cases have a relatively mild curve of Spee. However, if this curve is deep, and if the anchor molars have a mesial inclination and the anteriors have a lingual inclination, then the required increase in arch length to permit leveling of the occlusion can be attained by tipping the molars back to an upright position and tipping the anteriors forward to upright positions. If the amount of space required for such leveling would result in tipping the anteriors forward beyond an upright position, then the patient should be treated as an extraction case. 6. The majority of malocclusions are Class II, either Div. 1 or Div. 2. There are only a small percentage of Class I malocclusions, since well-alined and upright mandibular incisors are relatively rare in such malocclusions. Furthermore, the irregular lower incisors of many Class I cases do not show sufficient lingual inclination to permit their alinement without excessive forward tipping beyond an upright position. Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1969 Jun(307 - 311): Three-dimensional Control of Molars in Light Wire Technique with Auxiliary Springs - JACK PERLOW, D --------------------------------

Three-Dimensional Control of Molars in Light Wire Technique with Auxiliary Springs JACK PERLOW, DDS Displacement of molars in light wire technique is not uncommon. Despite the application of the usual tip-back, offset, and lingual bends it seems to be a universal complaint of light wire devotees. It not only occurs in Begg Technique, but can be a contingency in a number of other light wire techniques. Recently, one orthodontic company introduced an .020" tube insert for the .036" buccal tubes in the third stage to control unwanted distortion of the molars by having the .020" main archwire fit precisely and not float around in an

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oversized buccal tube. In an article in the January, 1968 Begg Journal, H. R. Foster discusses what happens to first molars as a result of Class 2 elastic traction, torquing sectionals and counteracting uprighting springs. Evidently, there is a positive need for molar stabilization and control in light wire techniques, especially in the Begg Technique. The method of molar control and stabilization that will be described in this article takes just a few minutes of preparation but will save perhaps months of corrective treatment. This idea originated about seven years ago, when I treated a first molar extraction case. In the course of space closure I found myself in a dilemma with tipped and rotated second molars. The corrective measures that were developed at that time were so highly satisfactory and so simple that I now use them routinely in all light wire cases both extraction and non-extraction. There is a basic principle that is fail-proof. It consists of setting up a closed mechanical system with a light, constant force to counter any undesirable tipping or rotating of the molars. A molar has three planes in which it can tip or rotate: mesio-distal (M-D), apical-occlusal (A-O), and bucco-lingual (B-L). In this paper let us consider for example a lower left molar that has rotated adversely so that its mesio-buccal cusp is displaced in a lingual direction and at the same time this tooth has tipped mesially. In the parlance of engineering mechanics using a dextral system, along the A-O plane the tooth has rotated clockwise and along the M-D plane counterclockwise. At the same time, in the B-L plane it may have tipped counter-clockwise. In addition, it has translated along the A-O plane gingivally or apically. Now it is possible to place appropriate counter-rotating devices on the buccal and lingual surfaces of the molar band to prevent or correct rotations along any of these planes. The springs described are for a lower left molar. A-O CC Spring A-O CC is a counter-clockwise apical-occlusal counterrotation spring. To use it an .018" minitube (The fabrication of these wonderful aids is described in AJO, June 1967, "Modifying the Edgewise Bracket for the Begg Technique".) is welded in a vertical position on the disto-lingual aspect of the molar band. The .014" A-O CC counter-rotation spring is inserted in the minitube with the lever arm perpendicular to the band surface. There should be at least two or three horizontal coils in the spring for maximum resiliency and power. A ligature tie is threaded through the loop at the distal end of the lever arm, carried through interproximally, and tied to the main archwire on the buccal side to activate the spring. This has a positive and incredible action which will not only correct the rotation in the A-O plane, but will effect some uprighting movement in the M-D plane as well (Figs. 1, 2 & 3). It should be understood that the minitube is welded to the band at the start of treatment. Whenever counter-rotation is required, it is a simple matter to remove the molar band for placement of the A-O CC spring and then to recement it. Following that, the spring is tied to the arch for activation. M-D C Spring M-D C is a clockwise mesiodistal counter-rotation spring (Fig. 4). A minitube is welded vertically on the disto-buccal corner of the molar band. Whenever mesio-distal counter-rotation is required the M-D C spring can be inserted without removing the molar band. With this spring you can actually get a toe-hold by tipping the crown back distally with the clockwise action of the spring. It is not suggested that one dispense with tip-back bends, but the action of these springs is positive and stabilizes the molar. The A-O and M-D springs combined can overcome displacements due to elastics, bicuspid uprighting springs and torque sectionals. These two auxiliary springs constitute stationary anchorage at its best. A gingival bend of the lever arm of these springs increases their uprighting action. B-L C Spring 108

B-L C is a clockwise buccolingual counter-rotation spring (Fig. 5). A minitube is welded vertically at the mesio-lingual corner of the molar band. The .014" B-L C spring slips into the minitube from the occlusal and goes over the contact point to hook onto the main archwire. The greater the occlusal deflection of the lever arm, the greater the counter-rotation action of this spring. It acts clockwise to correct a lingually tipped molar crown. This is sometimes called buccal crown torque. In some cases where a patient has been uncooperative in wearing crosselastics, this spring has been a way out by making the crossbite correction without any elastics. Conclusion • Three-dimensional control of molars in light wire treatment can be achieved with auxiliary counter-rotation springs. • These springs correct adverse first molar displacement in three planes in both extraction and non-extraction cases. • The springs maintain and reinforce mandibular anchorage with Class 2 elastic traction. • In molar extraction cases, the springs have no equal in the positive positioning of the second molars in their three planes.

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