Fragiskos's Oral.surgery (2007)

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F. D. Fragiskos

Impacted maxillary third molars may also be classified (Archer 1975), according to the depth of impac- tion compared to the second molar, into three Impacted catego- ries: Class A: The occlusal surface of the impacted tooth is at approximately the same level as the occlu7.8. sal surface of the second molar (Fig. 7.101 a). 1 Class B: The occlusal surface of the impacted tooth is Impacted Third at the middle of the crown of the adjacent Molar sec- ond molar (Fig. 7.101 b). Class C: The occlusal surface of the crown of the imRemoval of an impacted maxillary third molar is pacted tooth is below the cervical line of the dif- ficult, because of insufficient visualization of the adjacent molar or even deeper, contiguously area and limited access. Furthermore, other factors or even above its roots (Figs. 7.101 c–e). (re- duced aperture of the mouth, close proximity of the impacted tooth to the maxillary sinus, etc.) may Impacted teeth belonging to the third category are make the surgical procedure even more difficult. very difficult cases, because their extraction entails the removal of large amounts of bone, limited access, Classification. Impaction of the maxillary third and the risk of displacing the impacted tooth into the mo- lar (according to Archer 1975) may be maxillary sinus (Fig. 7.102). classified as: mesioangular, distoangular, vertical, horizontal, buc- coangular, linguoangular, or Fig. 7.100. Classification of inverted (Fig. 7.100). The tooth usually presents with impaction of maxillary third molars a mesial or distal inclina- tion, with the occlusal according surface positioned buccally. to Archer (1975). (1 Mesioangular,

7. 8 Extraction of Maxillary Teeth

2 distoangular, 3 vertical, 4 horizontal, 5 buccoangular, 6 linguoangular, 7 inverted)

Fig. 7.101 a–e. Classification of impacted maxillary third molars according to Archer (1975), depending on the depth of impaction compared to the adjacent second molar

Fig. 7.102 a, b. Maxillary third molars with deep, complete bone impaction. Their removal is considered difficult, because of the closeness to the maxillary sinus and insufficient visualization of the area

Types of Flaps. The types of f laps used are

triangular and horizontal: Triangular f lap: The incision for creating the f lap begins at the max- illary tuberosity and extends as far as the distal as- pect of the second molar, continuing obliquely up- wards and anteriorly (vertical incision) to the

vestibular fold (Fig. 7.103). In rare cases, when im- paction is deep and a satisfactory surgical field is necessary or when the impacted tooth covers the roots of the second molar buccally, then the vertical incision may be made at the distal aspect of the first molar (Fig. 7.104).

Incisions and Types of Flaps for Extraction of Impacted Third Molar Fig. 7.103 a, b. Diagrammatic illustrations showing the triangular incision (a) and ref lection of the f lap (b), indicated in certain cases of extraction of impacted maxillary third molars

Fig. 7.104 a, b. Variation of the triangular incision and f lap shown in Fig. 7.103 (the vertical incision extends as far as the distal aspect of the first molar). The mesial extension

of the incision is necessary due to the position of the third molar compared to the second molar

Fig. 7.105 a, b. Dia- grammatic illustrations showing the horizontal incision (a) and envelope f lap (b), for removal of impacted maxillary third molars

Horizontal (envelope) f lap: The incision for creation of this f lap also begins at the maxillary tuberosity and extends as far as the distal aspect of the second molar, continuing buc- cally along the cervical lines of the last two teeth, and ending at the mesial aspect of the first molar (Fig. 7.105). Often, after ref lection of the f lap, part of the crown of the impacted tooth is visible or there is bone protuberance over the crown. Because the bone in this case is thin and spongy, it may be re- moved from the buccal surface using a sharp instru- ment. If the buccal bone is dense and thick, then its removal is achieved using a surgical bur. Removal of Bone.

7.8.1 .1 Extraction of Third Molar

Impacted

The procedure for removing the impacted third molar (Fig. 7.106) is as follows. After making a triangular incision (Fig. 7.107), the mucoperiosteal f lap is ref lected (Fig. 7.108) and the buccal bone is then removed until the entire crown of the impacted tooth and part of its roots are exposed. Because extraction of the tooth in segments is not indicated, sufficient space must be created around its crown to be able to luxate the tooth. Thus, using a straight or double-angled elevator on the mesial aspect of the tooth, always buccally, the tooth is luxated carefully, posteriorly, outwards and downwards (Figs. 7.109, 7.110). Care of the wound and suturing are performed in the same way as described for all other cases of im- pacted teeth (Fig. 7.111).

Fig. 7.106 a, b. a Radiograph showing a maxillary third molar with distoangular impaction. b Clinical

photograph of the case shown in a

Fig. 7.107 a, b. Triangular incision completed. a Diagrammatic illustration. b Clinical photograph

Fig. 7.108 a, b. Ref lection of the f lap and exposure of the crown of the impacted tooth. Placement of the broad end of the periosteal elevator in the posterior position is indicated

to protect the tooth from becoming accidentally displaced into the infratemporal fossa or into soft tissues. a Diagram- matic illustration. b Clinical photograph

Fig. 7.109 a, b. Luxation of the impacted tooth using double-angled elevator. Extraction movements depend largely upon the relationship between the tooth and the maxillary sinus. a Diagrammatic illustration. b Clinical photograph

Fig. 7.110 a, b. Final luxation of the tooth. a Diagrammatic illustration. b Clinical photograph

Fig. 7.111 a, b. Surgical field after placement of sutures. a Diagrammatic illustration. b Clinical photograph

7.8. 2 Impacted Canines Impacted maxillary canines are quite common, and approximately 12%–15% of the population present with impacted canines. They are localized palatally more often than labially. Even though positions vary, the impacted canine presents five basic localizations (contralateral or ipsi- lateral and deep in the bone) as follows: 1. Palatal localization 2. Palatal localization of crown and labial localization of root 3. Labial localization of crown and palatal localization of root 4. Labial localization 5. Ectopic positions In young people aged 20 years or slightly older, impacted maxillary canines may be correctly aligned in

the dental arch after surgical exposure and orthodontic treatment. In older patients, especially after the age of 30 years, the above procedure is not a method of choice, because the risk of failure is greater. In such cases, surgical removal is preferred, if deemed necessary of course. The technique for removing impacted canines depends on the position of impaction (palatal or labial), the relationship of the impacted tooth to adjacent teeth, as well as the inclination of its crown. These fac- tors should be assessed before planning the surgical procedure. The localization of impacted canines is achieved using various radiographic techniques together with careful clinical examination. The most commonly used intraoral projections are occlusal projections, periapical radiographs and panoramic radiographs, while the technique employed for exact localization of the labial or palatal position of the impacted tooth is based on the tube shift principle, as described in Chap. 2. As far as the clinical examination is con-