Space Management in Pediatric Dentistry

Space Management In Pediatric Dentistry

 

                                                         

 

                                                      

 

     

Space Maintainers: Types And Indications Appliance Construction Long-term Evaluation And Significance Photo Bank: Space Management

 

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Introduction To Space Management Space management is an important responsibility of the general dentist and the pediatric dentist. Inadequate space management can cause problems which are long lasting and severe. The premature loss of primary teeth may cause loss of arch length, resulting in crowding of the permanent dentition, impaction of permanent teeth, esthetic difficulties, malocclusion, and other problems. We recommend prompt and appropriate space management therapies to help insure optimal lifelong dental health. The purpose of this chapter is to describe space management therapies. We will focus on the various types of space maintainers, when and how they are used, and how they are made. Our coverage will center on maintaining existing space once primary teeth have been lost prematurely, rather than on tooth movement. For information concerning the movement of teeth, we refer you to current textbooks of orthodontics or minor tooth movement

The best space maintainer is a primary tooth, as you see demonstrated in this radiograph. When nature's best space maintainer is lost prematurely, we need to intervene and maintain the space for normal development of the dental arches.

For example, this panoramic radiograph shows the premature loss of the mandibular right second primary molar, resulting in the tipping of the first permanent molar and consequent loss of space. This is an example of space loss which could have been prevented if a space maintainer had been placed after the primary tooth was removed.

This patient also has a missing mandibular right second primary molar, but a space maintainer will be placed here, keeping the permanent molar from drifting mesially. The critical importance of maintaining the space of a prematurely lost primary molar will be emphasized throughout the chapter.

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This photograph demonstrates a space maintainer placed on the mandibular right first permanent molar using 0.036 stainless steel wire soldered to an orthodontic band, with space being maintained for the underlying bicuspid.

Types Of Space Maintainers There are numerous types of space maintainers. They range from the very simple to those with numerous bands and wires. They can be constructed differently and used in different parts of the mouth. As we will cover later, some even have parts extending into the tissue. We feel the best way to make sense of the numerous types and subtypes of space maintainers is to start by classifying them broadly into four categories. They can be fixed or removable, and they can be unilateral or bilateral. A removable space maintainer, of course, can be removed. A fixed space maintainer is fixed (i.e., held) to a tooth or to more than one tooth. Fixation usually is done by cementing the space maintenance appliance in place. Unilateral space maintainers are fixed to one side of the mouth and bilateral space maintainers are fixed to both sides of the mouth. Fixed space maintainers can be unilateral or bilateral. Space maintainers also can be placed on the mandibular or maxillary arch. Consequently, we could have a maxillary removable bilateral space maintainer, or a mandibular fixed unilateral right side

space maintainer, and so forth. There are numerous variations on these basic themes. For example, some space maintainers are used for missing anterior teeth and some are used to preserve space for posterior unerupted teeth. The following pages will show the various types of space maintainers.

Fixed Bilateral Space Maintainer

This photograph shows an example of a fixed bilateral space maintainer. The patient is four years of age. The appliance is cemented on the two second primary molars. Fixed bilateral space maintainers on the mandibular arch often are called lingual arch space maintainers. Mandibular fixed bilateral space appliances generally are preferred by clinicians over removable space maintainers. Fixed appliances are easier to maintain and they are less likely to be removed, damaged, or lost by the child.

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Another lingual arch appliance for mandibular bilateral space maintenance is shown here. In this case, the appliance is attached to permanent teeth.The mandibular lingual arch space maintainer is used very commonly in the primary dentition and the mixed dentit on, where bands can be cemented to primary or permanent molars respectively. This is one of the most ubiquitously used space maintainers. It is even used on occasion in the permanent dentition when bicuspids are missing and maintaining space is necessary prior to orthodontic and/or prosthetic therapy.

Mandibular Removable Bilateral Space Maintainer

A mandibular removable bilateral space maintainer is shown on a six year-old. This youngster prematurely lost the mandibular right and left first and second primary molars. The disadvantages of a removable appliance are that it may not be worn by the patient and it is more susceptible to breakage or loss by the patient. To reiterate, most clinicians prefer to place fixed space maintainers if possible.

The same mandibular removable bilateral space maintainer is shown outside of the mouth. Note the wire attachments designed for the purpose of improved appliance retention

Fixed Unilateral Appliance

This photograph shows an example of a fixed unilateral appliance on the maxillary left side for a seven year-old patient. The photograph demonstrates the appliance after cementation. This appliance is referred to as a band and loop space maintainer and is a favorite among many clinicians.

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Fixed Bilateral Space Maintenance

The photograph presents a variation on the band and loop space maintainer; a mandibular left crown and loop space maintainer is shown. Note how the stainless steel wire is soldered to the stainless steel crown and the wire is bent so that it is adapted closely to the tissue. The crown and loop space maintainer is a type of fixed unilateral space maintainer where stainless steel crown therapy was necessary on the abutment tooth.

Bilateral Band And Loop Space Maintenance

The photograph demonstrates another variation on the bilateral use of fixed unilateral space maintainers. In this case, a fixed unilateral band and loop space maintainer was used on one side and a fixed unilateral crown and loop space maintainer was used on the other side. Crown and loop space maintainers can be used when a stainless steel crown is needed on a tooth which also is an abutment for a space maintainer. However, often band and loop space maintainers are used over stainless steel crowns. The rationale for using a band and loop space maintainer over a stainless steel crown is that if the band and loop appliance is no longer needed or if it fails, replacing the stainless steel crown will not also be necessary.

REMOVABLE UNILATERAL SPACE MAINTAINERS(ARE DANGEROUS)

This photograph shows two band and loop space maintainers, an example of the bilateral use of fixed unilateral band and loop space maintainers. These are very common types of unilateral space maintainers, and they often are used bilaterally. These are examples of dangerous space maintainers. They are removable unilateral space maintainers. We believe removable unilateral space maintainers should not be used. They are too small and present swallowing and choking dangers for children.

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Distal Shoe Space Maintenance

This appliance is called a distal shoe space maintainer or a distal extension space maintainer. It is used to prevent first permanent molars from moving mesially with the premature loss of second primary molars. The example shown is a crown with a distal extension segment soldered to the crown. The distal segment is extended into the tissue against the unerupted first permanent molar. The distal extension, also called a distal shoe, is used when the second primary molars are lost prior to the eruption of the first permanent molars (i.e., very premature loss).

The photograph shows a maxillary fixed bilateral space maintainer. This type of space maintainer also is known as a Nance Holding Arch or a Nance Appliance. Note the small acrylic button which will rest against the palatal tissue with this appliance. Some clinicians object to the button since it can create tissue irritation. Therefore, it is important that patients and parents be instructed to make sure that the patient meticulously flosses under the acrylic button. The Nance Holding Arch is used in situations where premature bilateral loss of maxillary primary teeth has occurred.

Prosthetics For Maxillary Anterior Teeth Maxillary Removable Bilateral Space Maintenance

This photograph shows a maxillary removable appliance, in this case a maxillary removable bilateral space maintainer. As suggested previously, removable appliances are not commonly used because of problems with the appliance not being worn and the frequent incidence of breakage and loss.

The appliance demonstrated in this photograph is used to replace missing maxillary anterior primary teeth. Cases like this are discussed at length later in the chapter and in the chapter covering pediatric restorative dentistry (it is an example of a type of maxillary anterior prosthesis).

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Clinical Indications For Space Maintenance

Indications For Space Maintenance Therapy

The following section of the space maintainer chapter is focused on the various indications for space maintenance therapy. As you have gathered by now, there are numerous types of space maintainers. Each different space maintainer is used in different clinical situations. We will review an array of different clinical situations relating to space maintenance therapy and give our recommendations for each of these situations. Hopefully, going through these clinical exercises will result in an understanding of when space maintenance is indicated and what type or types of space maintainers might be used. We will attempt to cover virtually every generic type of clinical situation requiring space maintenance therapy which clinicians will encounter in the primary and mixed dentitions.

This is a radiograph of a similar situation showing the missing mandibular right second primary molar. Again, is this a situation requiring placement of a space maintainer? http://depts.washington.edu37s001b.jpghttp://depts.

Yes; a space maintainer is indicated in the situation described in the previous pages for this four year-old child, as demonstrated by the drawing in red.

In this drawing, the mandibular right second primary molar is missing on a four year-old child. In your judgement, is this child in need of a space maintainer? This radiograph shows the placement of a distal shoe space maintainer extending to the mesial surface of the unerupted first permanent molar. The distal shoe space maintainer is intended to prevent the first permanent molar from erupting in a tipping manner over the underlying premolar

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This photograph demonstrates stainless steel crowns on the cuspid and the first primary molar, with a distal bar extending into the tissue, thereby preventing the first permanent molar from tipping mesially over the underlying premolar. This photograph shows the band and loop space maintainer which has been used to replace the distal shoe appliance. It is advantageous to replace the distal shoe, which extends under the tissue and is less hygienic than a band and loop space maintainer.

This is an example of a distal shoe space maintainer which has been successful in directing the eruption of the first permanent molar. However, since the first permanent molar has now erupted, the existing distal shoe appliance should be removed and a band and loop space maintainer can be placed.

Distal shoe space maintainers are discussed in the chapter on pediatric pulp therapy, particularly in terms of the importance of saving pulpally compromised second primary molars prior to the eruption of the first permanent molars. This is principally because of the technical difficulties associated with the placement of distal shoe space maintainers. The point we make repeatedly in discussions concerning pulp therapy is that it is best to save second primary molars using primary endodontic therapy (i.e., pulpectomy) when first permanent molars have not yet erupted. Most experienced clinicians prefer to avoid distal shoe space maintainers. However, one approach which may cause the process to be easier is to make distal shoe space maintenance a one appointment procedure. Most space maintainer protocol involves two appointments: the first appointment for extraction and impression taking, and the second appointment for placement and cementation of the appliance. In the case of distal shoe space maintainers, this means an additional local anesthetic experience for the child and a surgical incision immediately mesial to the first permanent molar so the distal shoe can be imbedded in tissue.

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The distal shoe space maintainer can be placed at the time of extraction of the second primary molar. If this approach is used, the impression must be taken and the appliance constructed prior to extraction of the primary tooth. The advantage is not having to go back at a later time and surgically make an incision for insertion of the distal shoe into the tissue so the distal shoe segment can abut against the permanent molar. Preformed (i.e., prefabricated) distal shoe space maintainers also can be used. Of course, preformed space maintainers are not customized (i.e., fitted) for the individual patient. They are placed at the time of the extraction appointment (i.e., a one appointment procedure is involved). Although they are not customized for the patient, using a preformed space maintainer is acceptable in many situations. Using a preformed space maintainer certainly is preferable to not using a space maintainer at all. Unfortunately, distal shoe space maintainers sometimes are not used when a child's behavior makes it unlikely that placement of the appliance at a second appointment would be successful. Of course, when distal shoe space maintainers are not used, the development of space problems results. Consequently, placement of distal shoe space maintainers can be planned as one appointment or two appointment procedures, and the choice of approach is left to the discretion of the clinician. As mentioned earlier in the chapter, it also is desirable to replace the distal shoe space maintainer with an appliance which is banded to the permanent molar once the permanent molar erupts. Consequently, using the distal shoe space maintainer and a subsequent band and loop appliance really involves several appointments.

In this drawing, the mandibular right first primary molar is missing on a six year-old child. In your judgement, is the child in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

As you see demonstrated in red, a space maintainer is indicated to prevent mesial movement of the second primary molar. A band and loop space maintainer is the best choice. It is especially important to start space maintenance therapy prior to the eruption phase of the first permanent molar, since the force of eruption of the permanent molar will exert a lot of pressure to push the second primary molar forward. The eruption phase of the permanent molar is the time of greatest force exerted against the primary molar.

For safety reasons, we recommend that you never use a removable unilateral space maintainer. If they are dislodged, they are so small that they can become a swallowing or choking danger.

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In this drawing, the mandibular right and left first primary molars are missing on a four year-old child. In your judgement, is the child in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

The lingual arch appliance, as demonstrated in the photograph, would be the appliance of choice for some clinicians in a situation where both primary first molars have been lost in the primary dentition. The bilateral appliance is very stable since it is anchored to two teeth.

Another example of a lingual arch appliance designed

for the primary dentition is shown in the photograph. Space maintenance is necessary to hold the second primary molars in position, especially as the first permanent molars erupt and create forces which otherwise would move the primary molars forward. Bilateral band and loop space maintainers can be used, as outlined in red. The bilateral band and loop strategy is our preferred approach, for reasons which will be explained later.

The major disadvantage to the use of a lower fixed bilateral lingual arch appliance in the primary dentition is the potential for permanent incisors to erupt later behind the lingual arch wire. In these cases, the appliance must be remade or bilateral fixed appliances can be placed. Some clinicians anticipate this potential problem and place bilateral band and loop appliances in the first place, so that interference with the eruption of mandibular incisors definitely can be avoided. We believe that most experienced practitioners would select bilateral band and loop appliances in situations where both lower first primary molars have been lost and before the eruption of the mandibular permanent incisors has occurred. This approach will prevent later problems with permanent incisors erupting behind the lingual wire.

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Nevertheless, the fixed bilateral lingual arch has the advantage of being a very stable appliance because of its two abutments. Many clinicians prefer it for that reason. Both are very acceptable approaches, and the choice of a fixed lingual arch appliance or bilateral fixed band and loop appliances is left to the preference of the individual clinician. Removable bilateral appliances are not the best therapeutic choice, especially for children in the primary dentition, although it is technically feasible to use them. The biggest problem is that children in the primary dentition age group are very unreliable when it comes to taking care of removable appliances, and the appliances are apt to become lost or damaged.

In this drawing, the maxillary right first primary molar is missing in this six year-old child. In your judgement, is the patient in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

Of course, unlike the removable unilateral appliance, the removable bilateral appliance is too large to be a serious swallowing or choking danger.

This is an example of a lingual arch wire which was placed before eruption of the permanent incisors, and a permanent incisor has erupted behind the wire. This problem can be avoided when band and loop space maintainers are used before the eruption of the permanent incisors.

A unilateral space maintainer is needed, as shown in red. Otherwise, the maxillary right second primary molar will drift mesially, thereby losing space. Once again, space loss will be especially severe if space maintenance is not used during the active phase of eruption of the maxillary right first permanent molar. The time of active eruption is commonly referred to as the dynamic phase of eruption

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space maintainer is an erupting first permanent molar. The dynamic phase of eruption is occurring, and this is when space maintenance is the most crucial.

This photograph shows the use of a band and loop space maintainer for this type of situation. Note that the maxillary right first permanent molar has not fully erupted. That is, it still is in the active phase of eruption. It is especially necessary for a space maintainer to be used during this dynamic phase of eruption.

In this drawing, the maxillary right and left first primary molars are missing in this six year-old child. In your judgement, is the child in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

Space maintenance is indicated in the situation shown in the drawing. As demonstrated in the drawing, one solution is to use a Nance Appliance or a Nance-type maxillary fixed bilateral appliance.

This photograph demonstrates the same principle, when a unilateral fixed space maintainer is needed on the maxillary right side. In this case, stainless steel crown therapy was needed on the second primary molar. Therefore, a crown and loop space maintainer was used. Please note that distal to the crown and loop

A Nance Appliance designed for the primary dentition is shown in the photograph.

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The drawing demonstrates another approach, where two fixed unilateral space maintainers are used (band and loop space maintainers). The choice of whether to use a maxillary fixed bilateral appliance or two fixed unilateral appliances is left to the preference of the clinician. As we have emphasized, fixed space maintainers are almost always preferred over removable appliances, although a removable bilateral appliance could be used in a situation like the one shown in the drawing.

In this drawing, the maxillary primary central and lateral incisors are missing in this four year-old child. In your judgement, is the child in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

What is your recommendation for a case like this? The patient is age three and has multiple missing maxillary teeth. A decision of whether or not to replace multiple missing maxillary primary teeth involves some potential controversy. Some clinicians prefer to replace maxillary anterior primary teeth in patients when more than one tooth is missing, and when it will be more than six months before eruption of permanent central incisors. This assumes the child's behavior is acceptable.

This photograph demonstrates two maxillary fixed unilateral space maintainers. A band and loop space maintainer is shown on the patient's right side and a crown and loop space maintainer is shown on the left. The choice of whether to use a band and loop appliance or a crown and loop appliance will depend partly on the restorative needs of the underlying teeth. As mentioned earlier in the chapter, it also is acceptable to use a band and loop space maintainer over a stainless steel crown. Please note, once again, in this photograph the maxillary left first permanent molar is in the dynamic eruption phase.

Their reasoning is that the presence of replacement teeth will hold the tongue in a better position. In this way, the development of a tongue thrust is less likely. We are aware of no well validated empirical research which actually demonstrates an association between missing primary anterior teeth and the development of tongue thrust. Nevertheless, replacement of multiple missing primary maxillary incisors is standard practice for some practitioners as a precaution. We cannot identify any serious risks to this approach, and it may indeed turn out

to be a useful strategy as research provides more information on the topic of tongue thrust development.

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Of course, many parents applaud the procedure because of the improved esthetics. There also are many pediatric dental offices and many dental schools where multiple missing primary anterior teeth are not replaced, at least routinely. Space loss usually is not a consideration, and monitoring for that problem can be used to insure that it does not occur. Most third party carriers also will not cover the prosthetics procedure (i.e., insurers will not reimburse you for the procedure and it will be an out-of-pocket cost for the parents).

A palatal view of the same appliance is shown in this photograph. As you can see, the appliance is based on the principle of banding posterior teeth and attaching prosthetic teeth to a wire running between the bands. It is a maxillary fixed bilateral appliance

As you can see demonstrated in red, a prosthetic appliance could be placed in this situation.

The photograph demonstrates another example of a maxillary fixed bilateral anterior prosthesis.

For those who opt to provide treatment in these situations, an excellent final result can be obtained, as shown in the photograph.

Although we almost always prefer fixed appliances, removable appliances can be used in situations where maxillary primary anterior teeth are prematurely lost. In this case, a removable appliance is shown where the primary central incisors are replaced.

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Prior to this juncture, our clinical situations have involved the primary dentition. Now we are going to move into the mixed dentition. In this drawing, the mandibular right second primary molar is missing on a nine year-old patient. The first permanent molar is present and fully erupted. In your judgement, is the child in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

This is an example of the situation seen in the prior drawing. The second primary molar has been lost and the first permanent molar is

present.

As shown in the drawing, a space maintainer is needed in this situation to prevent the bodily mesial migration and/or tipping of the first permanent molar. A removable unilateral appliance would be an unwise choice.

This photograph demonstrates the same case shown earlier. A fixed unilateral band and loop space maintainer has been placed. You will note also that the amalgam was removed from the permanent molar and a composite restoration was placed, and a stainless steel crown was placed on the first primary molar (in place of a very large amalgam).

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This is a space maintainer which is similar to the one shown previously. Please note the occlusal rest designed on the loop wire. This is placed to prevent the mandibular right first permanent molar from tipping and causing the wire to imbed apically in the tissue distal to the first primary molar. Thus, the occlusal rest helps prevent the tipping motion of the first permanent molar.

A closer view of the same occlusal rest is shown in this photograph.

Space management is indicated in this patient to prevent the mandibular first permanent molars from tipping or moving mesially. A fixed bilateral lingual arch space maintainer could be used, as shown in the drawing.

Right and left side fixed unilateral band and loop space maintainers also could be used, as shown in the drawing. Nevertheless, we believe most clinicians would select the fixed bilateral lingual arch appliance since the permanent lower incisors already are fully erupted. However, both the fixed bilateral and the fixed unilateral approaches are acceptable. Removable appliances can be used more successfully as children grow older. Nevertheless, even with older children, the loss and damage rate for removable appliances is high.

In this drawing, the mandibular right and left second primary molars are missing in this nine year year-old patient. In your judgement, is the patient in need of space management? If so, would you use a fixed or removable appliance?

A lingual holding arch designed for the mixed dentition is shown in the photograph.

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In this drawing, the maxillary right second primary molar is missing in this eight year-old patient. In your judgement, is the child in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

In this drawing, the maxillary right and left second primary molars are missing on this ten year-old child. In your judgement, is the child in need of a space maintainer? If so, would you use a removable or a fixed space maintainer?

A space maintainer is indicated in this situation, as shown in red in the drawing. A fixed unilateral band and loop space maintainer is an appropriate choice. It will prevent the maxillary right first permanent molar from moving forward, which would result in a loss of space for the unerupted bicuspid. A removable unilateral appliance would not be used because of swallowing and choking risks, even for older children.

The patient needs bilateral fixed space maintenance to hold the permanent molars in place.

An example of a maxillary removable appliance designed to hold the first permanent molars in place is shown in the photograph.

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Appliance Construction

be banded and selecting a band from the box of bands which appears to be the appropriate size for that tooth.

Once a decision is made regarding what type of appliance is needed and how it is to be used, the next phase of the space maintenance protocol involves creating the appliance. Four steps are involved in fixed appliance therapy: 1. Fitting the bands, 2. Impression taking, 3. Appliance fabrication, 4. Cementation. In the case of removable appliances, impression taking is the first step since bands will not be used.

Fitting The Bands

Occasionally we discover that the contacts between the teeth are so tight that separating elastics are necessary before the bands can be placed.

Selecting And Fitting Bands

The first step in the process of appliance fabrication is

selecting and fitting the bands. A trial and error method is used by most clinicians when selecting bands for an appliance. This is accomplished by estimating the proper size of band needed. The estimation is done by examining the tooth which will

The separating elastic is situated between the teeth where the band will be placed. One of the easiest methods of elastic placement is to use two threads of dental floss in order to hold the elastic. Next, gently "saw" the elastic between the teeth. Ideally, the elastic can be placed a few days before the band fitting appointment. If that were not possible, elastics could be placed at the same appointment. When both steps are planned for the same appointment, better separation will result if at least fifteen or twenty minutes is scheduled between elastic placement and the band try-in.

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The first step in the placement process is carrying the band to the tooth and placing it on the tooth with finger pressure. Further placement of the band can be done by pushing with a tongue depressor or the handle of a band seater. The patient can be asked to bite on the tongue depressor or handle of the band seater to push the band further apically.

The advantage of using a tongue depressor is that the band is almost never crushed during placement. Please note that the authors are using a dentoform for this series of photographs, to make it easier for the viewer to see the process.

The handle of a band seater also is a convenient instrument to use to push the band into place.

Some clinicians use a tongue depressor to aid in pushing the band down over the tooth. You can ask the patient to bite gently on the tongue depressor and the band is pushed down. HELPFUL HINT: As shown in the photograph, sometimes a tongue depressor which has been broken in half can be used more effectively than an unbroken tongue depressor, since the broken tongue depressor is smaller and easier for the child to bite on.

If the band is too large, it will be too loose a fit. If it is too small, the band will not go down over the tooth. We usually consider a nicely adapted band to be one that is placed on the tooth with some resistance and one which cannot be lifted off with finger pressure. We remove and place various bands until we obtain one which has a good fit.

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are desired, so that washout of the cement is less likely to occur.

Usually a band seater is used for further adaptation after initial placement. Please note how the band seater is placed on the tooth prior to having the patient bite down on the seater. Band seaters come in circular and triangular shapes. CAUTION: If you use the triangular seater, it is important not to place it next to the band in such a way that the patient can inadvertently drive the triangular piece into the cusp of the tooth. This may fracture the cusp.

A band pusher may be used for the final step in adaptation of the band. It is used to push the band against the tooth if a space remains between the band and the tooth. Tightly placed and well adapted bands

Note the use of band removal pliers. These are used during the placement and fitting process to remove bands. Of course, the same band removers are used to remove space maintainers when necessary in other clinical situations, for example when they are no longer needed due to eruption of permanent teeth.

Note that the top jaw of the pliers is placed on the occlusal surface of the tooth and the bottom jaw rests under the gingival margin of the band. When the pliers are squeezed the band moves occlusally off the tooth.

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Impression Taking

however, trays can be used or a "free-hand" (trayless) technique can be used.

Our purpose in this subsection is to cover impression taking techniques involved with space maintainer appliances. Once the bands have been fitted to the teeth, an impression is taken. The two impression materials most commonly used in pediatric dentistry for space maintainers are alginate and compound. Alginate is indicated primarily when removable appliances are being made. And as you know very well by now, removable space maintainers are rarely indicated and seldom used in pediatric dentistry. We will focus on impression taking with compound. Compound is an excellent impression material, especially for fixed appliances. In particular, it is accurate and stable, and you will see how these qualities make it highly suitable for taking impressions for space maintainers as we proceed through the chapter.

We will start with a demonstration of impression taking for fixed bilateral space maintainers, using a full arch tray technique. The following series of photographs, taken by using a typodont, show the compound impression technique used in our practices. Please notice the necessary armamentaria, a hot water bath, full arch tray, and compound.

Of course, alternative materials can be used. If you use other materials successfully and/or if your office routine is set up for other materials, by all means continue to use them. The most critical feature for an impression taking material for space maintainers is accuracy in obtaining the band registration around the tooth. Although we like compound when taking impressions for space maintainers, we are fully aware that many clinicians prefer alginate because of their familiarity with this material. Consequently, the impression material of choice is left to the preference of the individual. For purposes of this presentation, we will cover compound impression taking techniques for impression taking for both fixed bilateral and fixed unilateral appliances. We also emphasize these two techniques since they provide an opportunity to demonstrate two alternative impression taking procedures: taking impressions with and without impression trays. For bilateral impression taking, trays are always used. For unilateral impression taking,

The first step is softening the compound in the hot water bath.

The warm, pliable compound is placed in a child's size tray and warmed again if necessary.

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registration in the compound material. This is one of the significant advantages of compound material - the bands can be placed back into the impression material in exactly the correct place before pouring with stone.

After heating, the impression tray material can be cooled until it reaches the correct consistency and temperature. The essential consideration is to insure that the material is warm enough to flow but is sufficiently cool so not to burn the child. Having the patient stick out their tongue and touch the material is one method of insuring that the material has cooled satisfactorily. The tray can then be placed in the child's mouth. Individuals who are new to compound may believe that it might be difficult to remove the compound impression from the teeth because of hard compound setting in the undercut areas. This is not a problem, and experience with the material will bear this out for individuals who use compound for the first time. The compound material needs to be pliable, but not runny or it will take too long to set up. Ideally, the impression should be withdrawn after ten to fifteen seconds because children tolerate short impression times much better. A steady stream of air accelerates the set of the compound once it is inserted.

A photographic enlargement of the impression area around one of the banded teeth is shown to demonstrate that it is possible to see clearly the band

Compound is the impression material of choice because of its ease of use, its accuracy, stability, and tolerance by the child. Many dentists simply send the compound impression to the laboratory with no worry about dimensional changes in the impression. The bands can be placed nicely and easily in the impression. Usually, a highly identifiable ring can be seen in the impression material around the teeth where the occlusal aspect of the band has registered in the compound, and the bands are placed in the indentations made by the bands from the mouth.

This photograph demonstrates the bands placed in the compound impression. Because the compound material is firm the bands are mounted on a stable base. Nevertheless, it is often useful to heat tack the bands into the impression material before pouring. HELPFUL HINT: Keep the heat tack area away from the area where you will be placing the solder joints.

The photograph shows the cast with bands in the correct position waiting for construction of the space maintainer, in this case an anterior fixed bilateral prosthetic appliance

.

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This prosthetic appliance is discussed earlier in the chapter and in the restorative chapter, so let's go ahead and review how it is completed. After the impression, it is important to remind the laboratory to leave some spaces between the anterior primary teeth if the patient presents with that appearance, as was done with this patient.

A larger view of the final result is shown in the photograph. Most parents are very appreciative of the improvement.

Let's look at the appliance again. The teeth are banded with the wire running anteriorly. The teeth are acrylic. There are other designs which are acceptable; but this is one of the more common.

The major potential problem with this appliance involves eruption of the maxillary anterior permanent teeth, since the appliance obviously will interfere with their eruption. It is very important to stress with the parents that bringing the child in for regular recall appointments is absolutely necessary so that the appliance can be removed before it interferes with the normal eruption of permanent teeth. Of course, the dentist must be aware of the timing when the different teeth can be expected to erupt. An anterior radiograph also can be used for more accurate prediction of when the permanent teeth can be expected to erupt. The previous impression taking technique involved the process used for a fixed bilateral space maintainer, and an impression tray was used. What was described is the standard compound impression technique for fixed bilateral space maintainers, whether they are lingual arch appliances, Nance Appliances, or anterior prosthetic appliances. The next procedure we will describe is a technique for taking impressions for unilateral space maintainers, which we will call the nontray technique, where the impression is taken without an impression tray. Naturally, it is possible to use impression trays for impressions for unilateral appliances, and many clinicians take this approach using half-arch impression trays. The impression taking process using the half arch tray is the same as for taking a full arch impression which we just described. The choice of whether to use a half arch tray or the alternative technique without a tray is left to the preference of the practitioner.

Can you think of any potential problems with this appliance?

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We will discuss the nontray technique in detail, since it is a viable approach and has the advantage of eliminating the paraphernalia of the tray. It also may be interesting to some readers since the technique is not taught or used in many dental schools and hospital centers.

For the nontray technique, of course, no tray is used. You merely use the same compound material and the same technique for warming the compound. However, the amount of material used is approximately the size of a large thumb. It is taken to the patient's mouth, molded with the fingers, and held in place for ten to fifteen seconds. Just like the tray technique discussed earlier, the impression can be air dried and removed. This photograph shows the amount of warmed compound material to be used prior to placement in the mouth.

This photograph shows an impression after it has been removed. Please look carefully at the quality of definition of the impression of the band in the compound. Do you feel that the impression is of satisfactory quality? It is not. It could be difficult to place the band in the impression accurately. In these cases, it is important to take another impression

Do you believe that the definition in this impression is satisfactory? Yes; it is. This photograph demonstrates an impression with excellent definition, where the stainless steel band can be placed in the compound securely and accurately.

It is important to have good definition of the impression in order to properly place and adapt the band so it will not move when the impression is poured with a stone or plaster material. Still, we usually heat tack the band to the compound material once it is placed, which makes it

very unlikely that the band will become dislodged or float during the pouring process.

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This frame demonstrates the band in place, prior to pouring-up with the stone or plaster. Notice how nicely the band fits into the registration of the band in the compound. The accuracy of the compound makes this possible.

The impression is poured with stone. Once the stone is set, the poured impression is placed in the hot water bath and the cast is retrieved from the warmed compound. When the cast is retrieved, you will want to trim any excess stone from the cast and especially around the band

.

Appliance Fabrication Laboratory Fabrication Of The Appliance The next step in the process is appliance fabrication. Many family dentists and pediatric dentists employ a dental laboratory to fabricate their space maintainers. This is a completely satisfactory approach, assuming the dental laboratory is able to follow your instructions appropriately and produces appliances of good quality. It is even possible to have the laboratory come into the picture at various stages during the space management process. For example, you could send the laboratory the compound impression. One of the major advantages of compound impression material is that it is stable. It does not undergo distortion before the pouring process. In this way, the laboratory will do the pouring and the appliance construction.

Whether you use a laboratory or make the appliance yourself is a matter of personal preference. We have included instructions regarding how we construct appliances for those of you who will be involved in appliance construction. We will continue with the fixed unilateral space maintainer as our instructional example of appliance construction.

This photograph demonstrates using a pencil to sketch the outline where the wire will be adapted to the stone model

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This photograph shows the pencil adaptation where we want the wire to be bent to the cast. Please note how the outline of the drawing is wide enough so the wire loop will be large enough bucco-lingually to allow the bicuspid to erupt between the buccal and lingual segments of the wire.

Allowing space for the eruption of a bicuspid, as represented on this case, reinforces a very important point. WHATEVER APPLIANCE YOU ARE PLANNING, ALWAYS MAKE SURE THAT YOU ANTICIPATE HOW THE PERMANENT TEETH WILL BE ERUPTING AND MAKE ALLOWANCES FOR THOSE DEVELOPMENTS. It is essential to construct the space maintainer so that it does not interfere with the normal eruption of permanent teeth.

This photograph demonstrates the wire as it has been adapted to the cast. It should be emphasized that the wire needs to be adapted close to the tissue so that it will be comfortable for the child. The wire should be adapted in close approximation to the tissue, but not touching the tissue, so that the tongue can not get under the wire and cause irritation. It is necessary for the wire to be adapted closely to the band to produce a strong but not too bulky solder joint. At this point, the adapted wire can be anchored to the cast so that it can be soldered to the band. We use compound or sticky wax to heat tack the wire to the cast; and then we follow-up by pouring a thin mix of fast-set stone to the wire and the cast as the final anchorage step. It is important to keep both the sticky wax and fast-set stone clear of the areas of the solder joints, so that those materials do not interfere with the joints. Once the wire is anchored to the cast, check to make sure that its placement is satisfactory. At this point, the wire is soldered to the band using either an electric soldering technique or a flame soldering technique

Of course, it goes without saying that space maintainers should be constructed so they do not interfere with normal functions, or at least as little as possible. Wires and any other parts of space maintainers should be planned so that they do not interfere with eating and speech. HELPFUL HINT: Always to check to make sure that the child can close his or her mouth normally after placement of an appliance.

Various wheels are used for polishing bands, wires, and solder joints. The particular choice of polishing vehicle is a matter of individual preferenc 26 | P a g e                                       h t t p : / / d e n t a l b o o k s ‐ d r b a s s a m . b l o g s p o t . c o m /      

Fabrication Of The Single Appointment Preformed Space Maintainer

We will use this opportunity to discuss fabrication of the preformed (i.e., prefabricated) band and loop space maintainer. The preformed band and loop space maintainer is used by many clinicians since the appliance can be completed and placed in a single appointment. The tooth is extracted and the preformed space maintainer is cemented in place at the same visit, after fitting and fabrication of the appliance at chairside. Using preformed space maintainer appliances eliminates all laboratory work and allows placement of appliances at the same appointment when the surgery is done.

Note that the preformed band and loop space maintainer has female and male units. The tubes attached to the orthodontic band receive the wire loop which will abut to the adjacent tooth. The wire loop can be cut so the mesiodistal space requirement can be

determined and adjusted. Once the wires from the loop are placed in the tubes, the loop and tubes can be crimped together.

The crimping pliers for the preformed band and loop space maintainer are shown in the photograph.

The photograph demonstrates how the crimping is accomplished using the crimping pliers to crush the tube and wire together. Please note that some clinicians also solder one arm of the preformed appliance to obtain a stronger attachment of the tube and wire. This additional safety measure makes it more unlikely that the preformed appliance will come apart in the mouth and present a swallowing danger.

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swallowing danger. In this photograph, note that the buccal tube and wire have been soldered together for more secure retention.

The completed preformed band and loop space maintainer is shown. Note where the female and male units come together. The tube is crimped to secure the male unit to the female unit. It is a tube and wire appliance.

A preformed distal shoe space maintainer is shown in the photograph. Many clinicians prefer to use a customized band and loop appliance for most cases. However, many of these same clinicians prefer to use a preformed distal shoe appliance because of its relative ease of fabrication and the fact that a one appointment procedure is involved. Opting for a one appointment procedure will avoid a second local anesthetic administration and the difficulty of seating a customized appliance so it fits securely against the unerupted first permanent molar.

Preformed band and loop space maintainers also are configured with occlusal rests, which can be adapted at chairside.

Please note that some clinicians also solder one arm of the preformed appliance to obtain a stronger joining of the tube and wire. This additional safety measure makes it more unlikely that the preformed appliance will come apart in the mouth and present a

The photograph shows an example of a customized distal shoe space maintainer, which is attached to a stainless steel crown. An appliance such as this obviously is much more difficult to fabricate and place than a preformed distal shoe space maintainer. It also represents the absolute highest standard of customized care. Nevertheless, if the customized approach is not practical given all the circumstances, a preformed appliance certainly is better than no appliance

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Cementation Cementing The Appliance In Place The next phase in the process is cementation of the appliance. There are several important fine points related to the cementation phase of space management therapy. First of all, place the space maintainer in the mouth for a trial fit before you attempt cementation. It should fit like it does on the cast. Check to make sure that the wire of a band and loop space maintainer is in light contact with the tooth which is mesial to the edentulous space. With the wire in contact, you are sure tipping will not occur. In the case of a Nance Appliance, check to make sure that the acrylic button is in very gentle contact with the palatal tissue. Also check for large voids or spaces between the band and the tooth. If any are present, carefully use an instrument to push (burnish) the band to the surface of the tooth. In some cases, this step can be accomplished on the cast. Finally, make sure the child can occlude normally before you cement the space maintainer. It is a major interruption to be forced to remove a space maintainer after it has been cemented because it interferes with chewing. In the case of unilateral space maintainers and children who have extremely vigorous gag reflexes, you will want to consider running floss through the wire loop so that the space maintainer cannot be swallowed. A unilateral space maintainer possibly could be lost down the throat of a gagging, choking child without the protection of the floss.

The next step is the actual cementation of the appliance. Probably the most interesting issues related to cementation of space maintainers concern the continuing development of new cements.

The traditional choice, zinc phosphate cement, has been used for decades and still is used by many practitioners. It is a satisfactory material. It stores well, is easy to mix, and is well tolerated by patients. The glass ionomer cements, however, have gained huge popularity over the last decade. They also are easy to mix and are well tolerated by patients. In addition, glass ionomers release fluoride, are technique forgiving if isolation from oral fluids is less than perfect, and are very insoluble. Their lack of solubility is perhaps their most important advantage, since practitioners encounter less recurrent decay around and underneath bands. Bands rarely come off when glass ionomer cements are used, especially if the bands are tight fitting to begin with. You will start cementation phase of the procedure by isolating the tooth to be banded. Isolation can be obtained with cotton rolls. The tooth then is air dried. The tooth should be slightly moist (not desiccated). The cement can be mixed according to the manufacturers instructions. However, if you mix the cement so that it is sufficiently viscous, it will adhere to the inside of the band during placement and cementation and not cause difficulty by "running all over." Some clinicians stick a small section of masking tape over the band to prevent escape (i.e., "running") of the cement. This technique is fine if it works well for you. However, a slightly thicker mix of cement will prevent escape of the material in the first place. Once the appliance is cemented in place, remove the excess cement. One other advantage of the newer generation cements is that they are much handier when it comes to cement removal than the older generation cements. Have the patient bite together one last time to insure that the appliance is not interfering with the occlusion. It also is a good idea to show the appliance to the parent. Emphasize the importance of keeping the area clean. At this time, you can mention any potential issues about the space maintainer that you choose, in

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addition to re-emphasizing the importance of hygiene. For example, soreness for approximately twenty-four hours can occur. The child should avoid "playing" with the appliance with the tongue, which also can cause soreness (of the tongue). Temporary speech changes can occur with some appliances (especially Nance Appliances), but it is important to emphasize that the changes are temporary. In very unusual cases, short-lived sleep changes can occur, but once again these problems are transitional (and indeed very rare).

Although this cementing material is still commonly used, more and more dentists now are using glass ionomer cements. Glass ionomer cements have the advantages of fluoride release, excellent handling characteristics, low solubility, and good adhesion.

Many clinicians appoint patients who have had space maintainers placed for a quick check-up visit after approximately two-four weeks

This frame shows the cementation of a band and loop space maintainer with glass ionomer cement. This photograph demonstrates the cementation of a band and loop space maintainer with zinc phosphate cement.

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Long-term Evaluation And Significance Monitoring And Removal Ongoing Monitoring And Evaluation Of In Place Appliances

This photograph shows a lingual arch space maintainer with the teeth erupted. The appliance should be removed. This photograph demonstrates a tooth partially erupting between the wires of a space maintainer.

This photograph demonstrates substantial eruption of a tooth between the wires of a space maintainer.

This photograph shows a case where the tooth is almost completely erupted in a space maintainer. The space maintainer can be removed at this time.

A radiograph of a band and loop space maintainer is shown here. The space maintainer can be removed at this point.

This photograph demonstrates a situation where a crown and loop space maintainer had been resting against the primary cuspid. The primary cuspid has exfoliated. It is time to remove this space maintaine

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Conclusions And Significance

The best space maintainer is a well maintained primary tooth. But when these important natural space maintainers are lost, it is essential to implement a space management strategy. Appropriate space management therapy can save a child from esthetic disfigurement and save a family thousands of dollars in later orthodontic costs.

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A Quick Self Check This is a quiz at the end of chapter designed to give you a barometer of how well you understand the concepts covered in this chapter

1- The patient is a five year-old child with acute pain associated with tooth #K. What is your preferred choice of therapy for tooth #K? The patient is very cooperative and is able to tolerate long appointments.

A. B. C. D.

Pulpotomy Primary endodontics (pulpectomy) . Incision and drainage . Extraction

2- Regarding the patient in the previous question, if tooth #K were extracted, what type of space maintainer would be needed? A. B. C. D.

Band and loop space maintainor Distal shoe space maintainer (fixed) Distal shoe space maintainor (removable) Crown and loop space maintainor

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3- What type of space maintainer would you choose for the patient shown in the radiograph? The patient is a male, age nine. Your examination shows that all teeth normally present on the patient's right side are present.

A. B. C. D.

Nance Appliance Bilateral fixed lower holding arch Bilateral removable lower space maintainor Band and loop space maintainor

4- Regarding the patient in the previous question, what best choice for cementing the

appliance in place? A. B. C. D.

Zinc phosphate cemenl Zinc oxide eugenol cemenl IRM glass mnomer cemenl

5- Regarding the patient in the previous question, when would you decide to remove the space maintainer? A. B. C. D.

When Ihe bicuspids erupt When Ihe patient is ten years-old When the patient is ready to begin orthodontic therapy None of the above

6- The patient shown in the radiograph is a six year-old male and his mother reports that he has complained of severe spontaneous pain associated with tooth #B. Your examination indicates a lesion of moderate size on the mesial aspect of tooth #A and a large lesion on the distal aspect of tooth #B, which extends toward the pulp. All other maxillary teeth are present and are noncarious. You decide that extraction of tooth #B is warranted. What type of space maintainer will you advise for the patient? 34 | P a g e                                       h t t p : / / d e n t a l b o o k s ‐ d r b a s s a m . b l o g s p o t . c o m /      

A. B. C. D.

Nance Appliance, cemented lo teeth #'s 3 and 14 Upper right removable unilateral appliance Upper removable bilateral appliance Upper right band and loop appliance (or crown and loop appliance)

7- The patient shown in the photograph is a four year-old male who lost tooth #E in an accident. The child's father is concerned about his son's appearance. What advice would you give the father regarding space maintenance and/or a prosthetic replacement?

A. . You recommend a maxillary fixed bilateral appliance with a prosthetic replacement for tooth #E. B. . You recommend a maxillary removable bilateral appliance with a prosthetic replacement for tooth #E (i.e., a flipper). C. . You recommend a prosthetic tooth to replace #E which can be bonded to teeth #'s D and F. D. . You recommend that no space maintainer or prosthetic replacement be used in this case.

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8- Your examination of the patient shown in the photograph indicates that teeth #'s A and J will be restored and teeth #'s B and I will be extracted. What type of space maintainer will you plan in this case?

A. B. C. D.

. Fixed bilateral space maintainer with prosthetic replacement teeth for#'s E and F . Fixed bilateral band and loop space maintainers . Nance Appliance . Removable bilateral partial denture with prosthetic replacement teeth forf's E and F and acrylic space holders forf's B and I

99- Your examination of the patient shown in the photograph indicates that teeth #'s L and S will be removed. All other mandibular teeth will be restored. How will you plan for space maintenance?

A. B. C. D.

Right and left fixed band and loop appliances (or crown and loop appliances) Right and left removable space maintainors Fixed bilateral lingual holding arch Removable bilateral space maintainer

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10 A 6.0 year-old female patient is shown in the photograph. Based on your examination, you determine that tooth #J must be extracted. However, you also find that tooth #1 can be restored. You decide to place a distal shoe space maintainer to maintain space in the place of tooth #J. Once tooth #14 fully erupts, what is your plan regarding the distal shoe space maintainer?

A. . Leave the distal shoe space maintainer in place. B. . Remove the distal shoe space maintainer and do nothing else. C. . Remove the distal shoe space maintainer and replace it with a space maintainer which is not imbedded in tissue. D. . Remove the distal shoe space maintainer and place a removable unilateral space maintainer.

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