Orthodontic Treatment of Impacted Teeth. Adrian Becker

cannot match those of the orthodontist. This increases the risk of subsequent bracket detachment, repeat surgery and inappropriate traction direction. Any one of these factors may compromise periodontal health and gingival architecture.

       The orthodontist: Orthodontists also work in different ways, with widely differing appliance methods and customized traction device designs. There will be a periodontal price to pay for inappropriate directional traction, excessive traction forces and treatment inefficiency, not to mention varying quality standards of case completion.

      These three professionals and the patient are four individuals, each of whom has an influence, for better or for worse, on the desired treatment result in the present context. The number of factors that exist within the area of responsibility of each one is both infinite and diverse, making it impossible to arrive at a definitive sample that will enable a comprehensive scientific comparison to be formed between the two surgical approaches. As if that were not enough, enlarging the sample, by including meta‐analyses of different sub‐populations and different practitioners from different centres and using differing techniques, only increases this diversity.

      In summary, therefore, it can be stated that clear and authoritative answers to the question of surgical exposure preference are impossible to determine with any degree of validity. And this brings us back to outmoded, individual, surgeon‐orthodontist experience and opinion, with the dubious reliance on such literary guidance as may be available – namely, a large body of published studies based on retrospectively chosen samples – from which to attempt to draw some appropriate, if empirical, conclusions. In view of the fact that the Cochrane Collaboration arrived at identical conclusions, it is postulated that, at this time, a comprehensive, evidence‐based directive remains elusive.

Partial and full‐flap closure on the palatal side

      Impacted canines that are located on the palatal side are often palpable immediately beneath the palatal mucosa, which is itself firmly bound down to the underlying bone. In this situation, it is tempting to carry out the surgical removal of a circular section of the overlying mucosa and of the thin bony covering, in order to leave the tooth exposed. This has obvious advantages. In particular, the newly exposed tooth, when it finally erupts, will be favourably invested with attached gingiva. However, the palatal mucosal covering is very thick and the surgery will leave a broad cut surface, which will tend to close over unless its edges are substantially trimmed back and the dental follicle removed. Additionally, the exposure will need to be maintained using a surgical pack.

The result will be that, at the completion of the orthodontic alignment of the canine, this type of surgical approach will inevitably leave the palatal side of the tooth with a soft tissue deficiency and a long clinical crown. This is so even though, in the long term, the surrounding tissue will show the desired attached gingiva (Figure 5.8). This method has been favoured and promoted by Schmidt and Kokich in relation to palatally impacted canines. Their rationale is based on the assumption that the canines will, in many instances, improve their position and, in the course of time, erupt autonomously in the palate [41].

Fig. 5.8 Treatment for the right palatally impacted canine was performed with an open exposure technique. (a) The post‐treatment result shows attached gingiva of the palatal tissues covering most of the root, although the clinical crown length extends well down on the palatal side of the tooth, leaving several millimetres of root exposed on that side. The bone level is expected to be 8–10% defective compared to the untreated side. (b) The normally erupted left canine is shown for comparison.

      Their descriptive study offered a retrospective evaluation of the post‐treatment periodontal status of a group of patients who had been successfully treated by this method. However, their study was not based on a control group. Additionally, there appears to be no published controlled study that investigates the reliability and predictability of this treatment protocol.

      As described above in relation to labial/buccal exposure surgery, so too on the palatal side, where full‐flap closure allows the tooth to be exposed with the minimum of tissue removal and consequent reduction of surgical trauma. In addition, similar to the situation with the buccal side, it also requires the bonding of an attachment on the exposed tooth prior to suturing. When this is done and subjected to appropriate orthodontic mechanics, the final result will show that the bone support for the tooth, as well as the health and appearance of the muco‐gingival tissues, is very satisfactory, as will be demonstrated in the following chapters.

      In cases where there is a deeply located impacted tooth high in the palate, there is an accumulated body of evidence supporting a full‐flap closure approach [8–12, 26–28, 30–35]. The advantages of this recommended method are both qualitative and quantitative: the excellent clinical appearance of the crown length and gingival architecture and the number of objective parameters considered in a periodontal examination. In addition, there will be a reduction in post‐surgical pain and discomfort during the healing process [42–44].

       The relief of crowding to reduce canine displacement

      In cases where displacement of the canine has been caused by crowding or space loss (following early extraction of deciduous teeth), it is clear that relief of the crowding will facilitate spontaneous improvement in the position of the canine. However, time may not be on the side of the clinician who opts for this approach, since if there is too much delay the tooth may erupt through the oral mucosa. Nevertheless, if it is decided to proceed with this approach, a full case analysis should be prepared, leading to a diagnosis and treatment plan for the overall malocclusion. If, while the treatment is proceeding, the crowding is to be dispersed by distal movement of the molars, it will take longer to achieve the requisite available space in the canine region to permit the spontaneous improvement of the canine position. On the other hand, a premolar extraction will provide immediate relief of the crowding and an excellent opportunity for a self‐correction of the buccal displacement, and with it the disappearance of the potential periodontal hazard.

      In the treatment of a palatally impacted maxillary canine, a buccal approach to solving the crowding may sometimes be preferred, provided that its palatal displacement from the line of the arch is fairly minimal. Where the impacted tooth is vertically close to the CEJs of the adjacent teeth, the buccal approach may present a risk that interproximal bone may thereby disappear. Indeed, the greater the palatal displacement of the tooth, the greater will be the bony defect caused. Nevertheless, the buccal approach may be appropriate in cases where the teeth are marginally palatally displaced and situated higher in the maxilla. This will afford the opportunity for traction of the tooth by a more direct route to the labial archwire.

      Impaction of the maxillary canine, close to the line of the dental arch, may have been caused by the mesially tipped long axis that it presents, and by the consequent direct contact of the mesial crown incline with the distal side of the root of the lateral incisor. This type of impaction is relatively simple to treat. Indeed, it should correct itself if the crown of the lateral incisor is tipped mesially, thereby closing the anterior spacing and providing room for the canine within the arch. The process will automatically cause the root apex of the incisor to move distally, coordinating the orientation of its long axis with that of the canine. If, however, the tooth maintains its stubbornness and shows no sign of erupting, then a labial surgical approach to the very mildly palatally displaced canine will often be the most suitable and, in terms of the traction, the most direct treatment.

A conservative attitude to the dental follicle

      The dental sac or follicle is a fibrovascular capsule that has developed from a mesodermal condensation of cells on the outer surface of the