Vertical distraction osteogenesis combined with bilateral 2-step osteotomy for preprosthetic rehabilitation of edentulous mandible.

The aim of the current study was to appraise the effectiveness of distraction osteogenesis combined with bilateral 2-step osteotomy for the vertical augmentation of atrophic edentulous mandibles. To verify the predictability of this technique, we evaluated bone density and vertical bone gain of a cohort of 27 patients. The intraoral alveolar distractor was placed in the symphyseal area; then, it was left in situ for 2 months after surgery to consolidate the newly formed bone. A total of 189 implants were inserted. The main complications' issue was tied up to the neurosensory disturbances of the inferior alveolar nerve, which disappeared few months after the surgery.At the end of the distraction osteogenesis, a mean vertical bone gain of 10.5 mm evaluated by comparing preoperative and postoperative computed tomography was reached. Three months after the surgery, the radiologic data indicated that the difference in the mean bone density, recorded in Hounsfield units (HU), between the distracted bone and the preexisting mandibular bone was not statistically significant (P > 0.05). The last measurements done showed that the osseous density in the distraction chamber was higher than the original medullary bone density: the regenerated bones were more dense (876.8 [205.9] HU) than the preexisting medullary bone (312.1 [142.3] HU) and less dense than the preexisting cortical bone (1721.1 [170.4] HU) at the ninth month.In conclusion, this approach appeared to be a viable solution for the improvement of vertical volume in atrophic mandibles.