[Dental assisted distraction osteogenesis of the mandible. Results of an animal experimental study and initial clinical application].

In recent years lengthening of the human mandible by distraction osteogenesis has become an accepted treatment for correction of severe mandibular disto-basal discrepancies. Using extra-oral and intra-oral distraction devices the technique of osseous anchorage is usually preferred. To avoid the disadvantages of this method it is the aim of many research groups to develop a tooth-borne distraction. In the present animal study, six minipigs were treated 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 2-7 days, a mandibular lengthening of 9 mm was reached within a period of 9 days. This situation was retained using the distraction device for 6 weeks. After the removal of the apparatus, there followed a period of another 6 weeks of consolidation. The callus and bone formation and potential dental, periodontal and nerval reactions were radiologically examined and histological examination was performed at the end of the experiment. At 12 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. The mandibular nerve at the osteotomy site remained intact. The results justified transferring this procedure to humans. The clinical application of the device is presented.