Molar Extraction and Bone Grafting to Optimize Bone Stock for Future Mandibular Distraction

Mandibular distraction osteogenesis is a major modality in treating micrognathia associated with severe class II malocclusion. Shortcomings associated with mandibular distraction are often secondary to lack of adequate bone at the level of the osteotomies, either from insufficient original bone stock or paucity of bone secondary to previous surgical procedures. To address the challenge of limited bone availability at the distraction site, our institution has implemented a stepwise protocol in the patients with severe class II malocclusion and insufficient bone stock at the level of the planned osteotomy. Extraction of the mandibular third molar(s), followed by grafting of the resulting defect is performed initially. Either autologous bone graft or the combination graft material consisting of a mixture of demineralized bone matrix, bone morphogenic protein, and freeze-dried bone chips is used. Computed tomography is performed 9 months later to assess the bone stock at the level of the graft site. This technique is presented here with 100% graft take in all 9 grafted sites (6 patients). This technique appears to offer an effective way to prepare the mandible for optimization of subsequent mandibular distraction in patients with severely micrognathic mandibles and insufficient bone stock posterior to the third molar. Of note, both autologous bone and the mixture of demineralized bone matrix, bone morphogenic protein, and freeze-dried bone chips seem equally efficacious.