Orthodontic Treatment of Impacted Teeth. Adrian Becker
this tooth’s prognosis. On the other hand, the former bone graft had largely resorbed and had undergone replacement by the normal bone turnover process. This presented a more favourable matrix through which the canine could be drawn and which would increase the volume of accompanying alveolar bone.
The lateral incisor was erupted, aligned and its long axis paralleled to those of the adjacent teeth, with space provided for the canine, mesial to this incisor. The canine was exposed and bonded with an eyelet attachment in a closed exposure procedure. It was then drawn mesially and vertically through the former bone graft into the lateral incisor location, where it was uprighted until parallel to the adjacent teeth.
Fig. 5.10 (a) The initial records of the dentition showing the narrowed V‐shaped maxilla. (b) The oblique anterior occlusal view of the anterior maxilla shows the untreated cleft (yellow arrow) and the adjacent transposed lateral incisor (#22) and unerupted canine (#23). (c, d) Two identical anterior occlusal radiographs taken two days apart, immediately prior to and following the bone graft (green arrow) in place. (e) Alignment of the lateral incisor in the canine location and some spontaneous horizontal movement of the unerupted canine. (f) Following surgery and orthodontic traction, the canine has been aligned in the transposed order. The bony support of the canine and the lateral incisor is less than ideal for a good long‐term prognosis. (g) The broadened and aligned maxillary dental arch with space provided for the canine in the incisor location. Note the significant alveolar bony defect in the incisor area. (h) The anterior portion of the panoramic view, showing the canine in the transposed location and the unresorbed remnant of the bone graft (arrow). (i) The final arch shape and dental alignment. (j) The final transposed alignment following removal of appliances.
In the final analysis and following removal of the orthodontic appliances, the aligned canine and lateral incisor, in their transposed locations, were both invested in a good width of alveolar bone and the surface architecture was excellent. The canine exhibited a long crown with gingival recession and it is expected that, in time, the red and swollen gingivae will improve as keratinization of the mucosa occurs, depending, of course, upon appropriate oral hygiene and normal function. The appearance of these teeth may be further improved by judicial grinding of the point of the canine cusp and flattening of the labial prominence [50].
In the literature, from time to time we come across individual clinical case reports illustrating the eruption of teeth through bone grafts. In one such report [51], the patient had been treated for a large composite odontoma, which comprised a myriad of small denticles. The odontoma occupied much of the anterior maxilla, replacing bone and displacing the unerupted maxillary canine. When all the individual denticles of the odontogenic hard tissue tumour were surgically excised, a very large cavity in the bone remained. The presence of the space‐occupying benign entity had prevented the development of a significant potential volume of cortical bone. The authors had placed a graft of a synthetic bone substitute and subsequently erupted the impacted canine through it, in much the same way as was done in the last case (Figure 5.10).
In each of these difficult and extreme scenarios, a successful result of the treatment will almost always show good clinical and radiographic features. This is despite the necessity of having, post‐exposure, to erupt the teeth through surrounding alveolar bone, taking care to limit the removal of follicular tissue.
The deliberate aim of the tunnel method [30], mentioned above, is to bring a large canine down through the much narrower socket that was recently vacated by the extraction of its deciduous predecessor. This cannot be achieved without the resorption of bone lining the socket. Furthermore, in view of the lengthy time involved in bringing a severely displaced canine into its place in the arch, however rapidly this may be achieved, the lower part of the socket will surely have undergone osseous healing. The eruptive progress of this tooth cannot proceed in the direction of this vacated socket before physiological healing has deposited new bone directly in its path.
The aim of the treatment must, therefore, be to make the final realignment of the teeth as close as possible to the normal condition, regarding an attractive dental display, normal appearance of the gingival environment, healthy supporting alveolar bone and periodontal attachment. The following two anecdotal cases show that these treatment goals are achievable if, during the exposure of the impacted teeth, care is taken in the surgical handling of the dental follicle.
In the closed eruption approach, which we described earlier in this chapter, we recommended reflecting a wide soft tissue flap, while only opening the dental follicle itself to a very minimal degree – just enough to permit the maintenance of haemostasis while the bonding of a small attachment is performed. The remainder of the follicle survives intact, which means that all other parts of the crown of the tooth are invested in follicular tissue that, when traction is applied, will presumably initiate bone resorption in the normal way. The break in the integrity of the follicle occurs solely at the site of the attachment, where only a minimum of bone will have been removed. It is open to speculation whether repair of the follicular tissue may occur over a bonded attachment and whether its integrity will be fully restored around the steel ligature to which traction is applied.
This idyllic scenario would appear to be most unlikely to occur in practice. Let us set aside for a moment the reasons why a conservative attitude to the dental follicle works so well, because the fact remains that, in these cases, post‐orthodontic corrective periodontal flap and graft procedures are almost entirely superfluous in both the short and the long term. For the most part, the previously impacted teeth are impossible to distinguish, periodontally, radiographically and aesthetically, from their unaided neighbours and antimeres (Figures 5.11 and 5.12).
Quality‐of‐life issues following surgical exposure
Young patients who are about to undergo surgical exposure of an impacted tooth need to be informed how the procedure may affect their daily life in terms of pain, function, speech and the several other aspects that involve the oral cavity. The risks and benefits of the intended treatment must be clearly set out. Patients are often apprehensive at the thought of surgery, particularly if they are young and healthy with little or no previous experience of surgical procedures. The incidence and magnitude of these challenges are all part of the post‐surgical follow‐up, of which patients and their parents must be apprised. These aspects of the procedures constitute information that the law requires to be explained to them, in order for them to sign a statement of informed consent. While this is true of all types of orthodontic treatment, it is particularly so where surgery is involved.
A number of articles have recently appeared in oral surgery journals regarding these parameters within the context of the extraction of third molars. However, it is a matter of surprise that there is a significant paucity of published works that relate to quality‐of‐life (QoL) issues in the context of the surgical exposure of impacted teeth. The result has been that the information available to both clinicians and patients is often based on a single anecdotal episode or on the biased reports of individuals who have themselves experienced some form of oral surgery. Information thus gleaned is notoriously unreliable and will rarely have any application to the particular surgical exposure then planned.
This lack of professional information was the motivating factor for the prospective clinical studies that were undertaken in Jerusalem, to quantitatively assess the various aspects of QoL consequential to the performance of both open and closed surgery [42–44].
For the purpose of the QoL study, two groups of patients were assembled. One group included young patients who were scheduled for open surgery and the second group for closed surgery. On the day the exposure was