An improved appliance for the pre-surgical orthodontic preparation of the cleft case for secondary bone grafting

Abstract

THE procedure of secondary bone grafting in cases of alveolar clefts to stabilise an orthodonticaUy achieved position of the maxillary fragments has increased during the seven years since Johanson's description of the technique in 1961. The orthodontic appliances used have evolved during this period of time and in this country the most commonly used appliance is probably similar to that described by Grossman in 1963. It consists of silver cap splints fabricated to fit, and cemented on to the teeth of the fragments it is desired to reposition, the expansion screw being attached to the splints by acrylic resin, the whole comprising a rigid structure. This design has been found to have limitations in several important respects. I. Unilateral Cleft Cases with Severe Collapse of Maxillary Fragments.--In cases where the expansion of the fragments that is necessary exceeds that provided by the screw in the appliance, the appliance must be removed in its entirety from the patient and the screw replaced. The attendant danger of relapse during the period while the appliance is not in position and the possible danger of distortion of the appliance during its removal or during laboratory procedure render6 this procedure both hazardous and time-consuming. 2. Bilateral Cleft Cases.--Where both lateral movement of the lateral maxillary fragments and a labial movement of the premaxillary fragment is required, resort would have been made either to the procedure already described and a change of direction of expansion made by constructing essentially a new appliance, or alternatively, it has been suggested that screws be included to carry out both movements within the same appliance. If the latter course is pursued the appliance, already somewhat cumbersome, has to be increased in size and coverage of the palate to accommodate both screws. Design problems may also arise as a result of the complexity of the movements attempted. 3. Retention of Maxillary Fragments.mSince, the appliances described, their removal and replacement is difficult and not without danger of relapse, it has been customary to retain the position of the fragments with the appliance used to achieve this position. As has been noted, the appliances are of necessity bulky and occupy a considerable volume of the oral cavity and interfere with normal mastication and possibly