Orthodontic Treatment of Impacted Teeth. Adrian Becker

one or more of the many aspects of the treatment, leading to a poorer periodontal prognosis and an inferior appearance of the treated result. The fact that the patient, the surgeon or the orthodontist may find the arrangement inconvenient might mean that the orthodontist cannot be present, but that must be recognized as a less than ideal situation. Not only does the presence of the orthodontist at the surgical episode serve the patient’s best interests, it also speeds up the procedure, reduces discomfort and eliminates legally vulnerable misunderstandings and mistakes. The presence of the orthodontist is comforting and highly appreciated by the patient/parent and goes a long way to encourage confidence and trust.

      Bonding an attachment during surgical exposure is not a function that a surgeon is adept at performing. It represents a highly technique‐sensitive succession of tasks, which involve the following actions, all of which must be done simultaneously: lengthy flap and tissue retraction, and establishing and maintaining a completely dry, clean and blood‐free surface of enamel while etching, rinsing, drying, painting with resin, light‐curing, loading composite on the attachment, placing and curing. This delicate string of functions is not routinely performed by surgeons. Orthodontists, on the other hand, often successfully bond hundreds (literally!) of attachments every week.

      The desirable location of the bonded attachment is strictly in the orthodontist’s realm and it is not always possible to determine the location before surgery. Furthermore, when the exposed tooth comes into view, a decision may have to be made that may dictate the need to draw the tooth in a direction that had not previously been contemplated. This, in itself, may require an on‐the‐spot change in the predetermined bonding site. The luxury of being able to have ‘second thoughts’ at this crucial point in the treatment should not be surrendered lightly.

      In a similar vein, the application of accurate directional traction from a customized spring mechanism is of considerably greater value if it is performed by the orthodontist under the cover of the pervading anaesthetic.

      Notwithstanding this discussion, in cases of extreme displacement of an impacted tooth, extraction may be the treatment of choice. This may be due to the difficulty in attachment bonding or the inadvisability of performing an open surgical exposure. There can be no doubt that teamwork, combining the skill of the surgeon in controlling bleeding and the parallel skill of the orthodontist in bonding attachments, offers superior assurance against bond failure and towards overall treatment success.

      One must not lose sight of the fact that it is the orthodontist who must follow through the remaining many months of active treatment. Failure to deliver the desired result will often sour the patient–doctor relationship and, moreover, may lead a resentful patient to seek legal recourse.

Aims of surgery for impacted teeth

      It must be recognized that, other than transplantation, there are no surgical methods by which an impacted tooth may be positively and actively aligned. The best that surgery can do is to provide the optimal environment for normal and unhindered eruption and then live in hope that the tooth will oblige. In consequence, the recommendation in the latter part of the twentieth century was that those teeth that the oral surgeon considered worth trying to recover were widely exposed and packed with some form of surgical or periodontal pack, in order to protect the wound during the healing phase and prevent re‐healing of the tissues over the tooth. The expectation was that the tooth would erupt spontaneously and could then be aligned with orthodontic treatment. Several other steps were often taken, depending on the individual preferences and beliefs of the surgeon, with the aim of providing that ‘extra something’ that would further improve the chances of spontaneous eruption. These measures were frequently empirical in nature and would include one or more of the following:

       Eliminating the follicular sac completely, down to the cemento‐enamel junction (CEJ) area.

       Removing all bone around the tooth, down to the CEJ area, in order to dissect out and free the entire crown up to the coronal portion of the root of the impacted tooth.

       ‘Loosening’ the tooth by luxating it with an elevator or extraction forceps.

       Bone channelling in the direction of the desired movement of the tooth.

       Packing gauze or heat‐softened gutta percha into the area of the CEJ, under pressure, in order to apply force to deflect the eruption path of the tooth in the preferred direction.

      Back in the early 1970s, it was rare that the general dentist referred such patients to the orthodontist, at least not before full eruption had been achieved and then only to assist in moving the tooth horizontally into line with its neighbours. Before full eruption took place, the problem was considered to be within the realm of the oral surgeon. In many cases, ‘success’ in achieving the eruption of the tooth was indeed pyrrhic and sometimes actually caused a greater problem, particularly in relation to the periodontal condition of the newly erupted tooth and its survival potential – namely, its prognosis. This most unfortunate consequence was the result of the aggressive and overenthusiastic surgical techniques that were then being used, most of which typically left the tooth with an unaesthetic and elongated clinical crown, a lack of attached gingiva and a reduced alveolar crest height [9–13]. Just occasionally, these damaging procedures initiated an invasive cervical root resorption lesion, which created a state of non‐response to orthodontic traction and failure in generating its eruption.

Surgical intervention without orthodontic treatment

      Notwithstanding my description in the first part of this chapter, there are situations and conditions in which surgical intervention without orthodontic treatment is called for and indeed appropriate. Thus, in cases in which the impacted tooth is the only clinical problem (the occlusion and alignment being otherwise acceptable), the question that needs to be addressed is: what surgical methods are available that may be expected to provide a more or less complete solution without orthodontic assistance? In order to discuss this question, it is necessary to provide a description of the position of the impacted tooth that is being encouraged to respond to this kind of treatment.

       Exposure only

The most obvious example is a superficially placed tooth, palpable beneath the bulging gum. This type of impaction may be found in relation to the maxillary canine (Figure 5.1), or in the mandibular premolar area (see Figure 1.8) or even the maxillary central incisor. The usual cause of this condition is where very early extraction of the deciduous predecessor was performed while the immature permanent tooth bud was still deep in the bone, with as yet inadequate eruption potential. Healing then took place, the gum closed over and the permanent tooth was unable to penetrate the thickened mucosa. Removing the fibrous mucosal covering or incising and re‐suturing it to leave the incisal edges exposed (Figure 5.2a–c) will generally lead to a fairly rapid eruption of the soft tissue impacted tooth, particularly in the maxillary incisor area. The more the tooth bulges the soft tissue, the less likely will be a re‐burial of the tooth during healing of the soft tissue, with the consequent rapid eruption of the tooth.

Fig. 5.1 (a) A 16‐year‐old female exhibits an unerupted maxillary left canine, which has been present in this position for two years and has not progressed. (b) The tooth was exposed and the flap, which consisted of attached gingiva, was apically repositioned. (c) At nine months