of the tooth to occlusally directed light forces, despite the fact that it may often have to resorb a thick layer of bone in the process. This is even the case where alveolar bone in CCD patients is considered to be particularly dense and the largely acellular cementum on the roots of their teeth is associated with slower resorption [49].
Bone graft and the impacted canine
A 9‐year‐old female patient was accepted for treatment by an orthodontic resident in the cleft palate unit of the Hebrew University‐Hadassah School of Dental Medicine in Jerusalem. The patient, who was in the middle period of the mixed dentition, had a unilateral cleft lip and palate of the left side (Figure 5.10a). The palate was very narrow and V‐shaped and she had a bilateral and anterior crossbite.
When the patient was admitted for the autogenous bone graft that would close off the cleft (Figure 5.10c, d), the lateral incisor on the distal side of the cleft was transposed with the unerupted maxillary canine (Figure 5.10b). These two anterior occlusal radiographs were recorded the day before and the day after the placement of the graft, for the purpose of checking the outcome of the procedure.
A rehabilitation treatment plan was established for the orthodontic part of the overall correction. The plan was to align the two teeth in their transposed relationship, rather than attempt to correct it. This was based on the periodontal assessment of the long‐term relative merits of the two therapeutic possibilities. It was considered that moving the lateral incisor bodily into the area of the former cleft, where there was a glaring deficiency of alveolar bone, would seriously undermine 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).
