Читать книгу Orthodontic Treatment of Impacted Teeth - Adrian Becker - Страница 108

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].