The fate of developing teeth in mandibular lengthening by distraction: an experimental study

Purpose: The purpose of this study was to observe developing teeth in a len gthened mandible after distraction. Material: Ten mongrel dogs with deciduo us dentitions were used. Methods: A corticotomy was carefully made around a tooth bud and the external distracter (Orthofix M-100(R)) was connected. A fter a 5-day latent period, distraction was started at a rate of 0.75 mm pe r day for 10 consecutive days. Then, the lower jaw was stabilized by an ext ernal fixation to allow ossification. While the operation was performed on the left side (Distraction group), the contralateral side was studied for c omparison (Control), In addition, a corticotomy, artificial fracture and ex ternal fixation were carried out to confirm the influence of the operation (Fracture group). Then macroscopic, radiographic and histological evaluatio ns were carried out. Results. In the Distraction group, the space between t he wall of the dental follicle and the crown expanded as distraction began. The end of the calcified root became wider and irregular during the distra ction period, and finally, the apex closed. Tn the Fracture group, the teet h erupted although slight alterations of the root shape were observed in as sociation with the operation period. Conclusion: The root became irregular, but the teeth erupted within the distraction area, (C) 2001 European Assoc iation for Cranio-Maxillofacial Surgery.