Mandibular distraction osteogenesis. Preliminary results of an animal study with a dentally fixed distraction device.

Lengthening of the human mandible by distraction osteogenesis has become an accepted treatment for correction of severe mandibular disto-basal discrepancies in recent years. This usually entails the deployment of extra-orally located distraction devices. This type of device often causes conspicuous scarring. To avoid this scarring, an intra-oral device is to be developed. In the present animal study, 2 "Troll" mini-pigs and 2 "Yucatan" micro-pigs were fitted with a new solely dentally fixed orthodontic device for mandibular distraction osteogenesis. Following bilateral osteotomy in the dentigerous area of the mandibular body and a latent period of 2 to 7 days, the apparatus was activated 1 mm per day. Within a period of 9 days, a mandibular lengthening of 9 mm was reached. This situation was retained using the distraction device for 6 weeks. After removal of the apparatus, there followed another 6-week period of consolidation. During the experiment, the callus and bone formation and potential dental and periodontal reactions were radiologically examined and underwent histological examination at the end of the experiment. Twelve weeks after the mandibular lengthening, the osteogenesis in the distraction areas was complete. No destructive processes were recognizable, either at the roots or at the periodontium of the teeth near the osteotomy gap. Lengthening of the mandibular body using distraction osteogenesis with the help of a solely dentally fixed distraction device is thus feasible and can, in the future, become the appropriate treatment in the correction of severe mandibular deficiency.