Orthodontic Treatment of Impacted Teeth. Adrian Becker

normally, without orthodontic treatment.

      Courtesy of Professor L. Shapira.

       Exposure with pack

Taking this one step further, it is clear that an impacted tooth that is buried much deeper in the alveolus will be much more prone to being re‐enveloped by its surrounding healing tissues. It will require a more radical exposure procedure to ensure its patency. In addition, it may need a pack to hold back the tissues during the post‐surgical days and weeks, in order to ensure subsequent direct access to the tooth. While the surgeon may ultimately be rewarded with spontaneous eruption, this will inevitably take longer and the extent of the surgery may lead to a compromised periodontal result (Figure 5.3).

Over‐retained deciduous teeth have been defined in Chapter 1 as teeth that are still present in the mouth when their permanent successors have reached a stage of root development that is compatible with their full eruption (two‐thirds of expected root length). These deciduous teeth are to be considered as obstructing normal development. While it follows that they should be extracted, provision should be made at the same time to encourage the permanent teeth to erupt quickly.

Fig. 5.2 (a) Soft tissue impaction of maxillary central incisors. (b) Apical repositioning of both labial and palatal flaps to leave the incisor edges exposed.

      Courtesy of Professor J. Lustman.

Fig. 5.3 Following exposure, attachment bonding and packing the unerupted tooth, it erupted spontaneously, but the bone level was compromised.

      Permanent teeth whose eruption has been obstructed or delayed are abnormally situated deep in the alveolus and are in danger of becoming re‐buried by the healing tissue of the evacuated socket of the extracted deciduous tooth. Accordingly, the crowns of the teeth should be exposed to their widest diameter and a surgical or periodontal pack placed over them and sutured in place for 2–3 weeks. This will encourage epithelialization down the sides of the socket and should prevent the re‐formation of bone over the unerupted tooth.

      In order to maintain the surgical opening, most surgeons and periodontists today will use a proprietary pack, such as CoePak™, which doubles as a dressing for the surgical wound. Alternatively, particularly with maxillary palatal canines, placement of a removable acrylic plate, which will have been prepared before surgery, can be employed in order to retain a small pack over the exposed tooth [14]. Regardless of the method, however, and parallel with the concern for maintaining the patency of the exposure, one must exercise appropriate concern to hold the space for the anticipated eruption of the impacted tooth. Space loss in the mixed dentition may often be very rapid and may result in halting the progress of the erupting tooth by its proximal contact with the adjacent teeth. It is essential that this aspect be considered and the appropriate provisions made and followed closely.

      ‘Expose‐and‐pack’ was revived and reintroduced as an approach and has been recommended for the treatment of severely palatally displaced maxillary canines [15]. This method has been recommended as being suitable for spontaneous resolution even in some cases of quite severe displacements. It creates the possibility of at least partial eruption through the surgically created and pack‐maintained opening and permits relatively easy access for attachment bonding. Subsequent alignment of the tooth can then be beneficially undertaken, utilizing simplified appliance therapy. However, validation of the method by a disciplined clinical study has not been done and the evidence in its favour must therefore be considered anecdotal at present.

      Notwithstanding its benefits, it must be noted that there are a large number of situations, particularly concerning maxillary canines, where this method is inappropriate. Examples of such situations include the following:

       Inadequate space in the dental arch to accommodate the tooth along any part of an intended path on the way to its normal location.

       The surgeon may realize at the time of surgery that spontaneous eruption appears unlikely to occur. Without the facilitating element of a traction appliance, he or she may be tempted to consider more radical surgical short‐cuts, such as those listed above, despite the likelihood of thereby causing irreversible damage to the periodontium.

       Surgical exposure of a canine that is associated with severe resorption of the root of the adjacent incisor is difficult to accomplish without secondarily and inadvertently exposing the resorbed root apex. In this situation, leaving this highly sensitive area open will inevitably risk de‐vitalization of the incisor.

       In a situation where an impacted tooth is in a grossly ectopic location, spontaneous eruption is unlikely to occur and assisted and directed traction is unavailable to bring about its resolution, unless suitable means were prepared ahead of time as a precautionary measure.

       With an unerupted canine that is located high on the labial side of the alveolar ridge, above the attached gingiva band, if a direct, window technique, open surgical exposure is performed, one would of necessity have to launch into a series of reparative periodontal tissue grafts at the conclusion of the orthodontic treatment. Such grafts would be needed to substitute for the thin and vulnerable oral mucosal attachment that would otherwise result.

       For an adult in the 40+ age group with an unerupted and untreated maxillary canine, the eruptive potential of the tooth is likely to have exhausted itself long ago and the tooth is unlikely to respond to the surgical exposure.

      There are additional situations in which the use of open surgical exposures will be contraindicated, even when extrusive orthodontic traction is indeed available. Many of these situations will be discussed in the ensuing chapters of this book.

       Exposure with pressure pack

      It is common to find mesial impaction of a third molar, beneath the distal bulge of the second. It is less common to find a mesial impaction of a mandibular second permanent molar, beneath the distal bulbosity of the first permanent molar. The two situations, however, have similar characteristics. In their mildest form, they both present a condition that may sometimes respond merely to surgical intervention and packing. This is carried out by the exposure of the occlusal surface of the tooth and the deliberate and forceful wedging of a pack in the area between the two teeth and leaving it in place for 2–3 weeks. During this period, the pressure caused by the pack will often succeed in eliciting a small distal movement of the impacted molar, possibly causing it to erupt more freely when the pack is removed. The degree of control that is available to the operator in judging the amount of pressure to be applied is minimal and the extent to which the pack interferes periodontally is impossible to assess. Therefore, damage to the periodontium of the two adjacent teeth becomes a distinct possibility. Success in bringing about an improved position of the tooth may exact a cost in terms of the health of its supporting structures.

      As an alternative to the use of a pressure pack, some orthodontists advocate the use of brass wire [16] or elastic separators, in order to apply a similar disimpacting force. Simple remedies of this kind may be effective in situations where the discrepancy is minor. However, in many of these types of cases the brass wire and the elastic separators will need frequent tightening, replacement and renewal. Briefly stated, the method is unreliable at best.

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