下顎骨仮骨延長症例の中期変化 延長後５年以上経過して

Abstract

Five-year follow-up after mandibular distraction lengthening was performed on three cases with hemifacial microsomia (two unilateral and one bilateral). The patients were in the growth stage and orthodontic treatment using functional appliances with or without multi-bracket appliances were carried out in this period. The examinations focused on the changes of facial appearance and occlusion, and on development of teeth in the distracted areas. The findings were as follows:1. In unilateral patients, facial asymmetry was improved immediately after distraction, while the occlusion became worse presenting lateral crossbites and open bites. After five-year follow-up, the occlusions were stable though they showed crowding. However facial asymmetry significantly recurred in one patient.2. In the bilateral case, the effect of mandibular distraction was prominent. The facial profile and occlusion were improved markedly. Nevertheless, the subsequent orthodontic treatment with multi-bracket appliances, and mandibular osteotomies after the completion of facial growth were required to establish the final occlusion and to gain a good profile.3. The development of teeth in the distracted areas showed various results, i. e., normal development, malpositioning and disturbance of root formation.These findings suggested that although mandibular distraction was useful for the treatment of small mandibles, further refinement of this technique is required considering occlusal changes, recurrence of facial asymmetry and development of teeth.