Spontaneous mandibular fracture as a complication of inferior alveolar nerve transposition and placement of endosseous dental implants in the atrophic mandible: a review of the literature and a report of two cases and their nonsurgical conservative management

Objectives: Severe atrophied edentulous posterior mandible with inadequate bone height superior to the inferior alveolar canal may require transposition of the inferior alveolar nerve in order to insert dental implants. Mandibular fractures are considered a rare complication of this procedure. Implant-related spontaneous fractures of the mandible represent 0.2% of patients with inserted implants in an edentulous mandible. This report presents two cases of mandibular fractures that occurred 3 to 4 weeks after inferior alveolar nerve transposition, and were managed successfully by conservative nonsurgical treatments. Method and materials: Overall, 132 procedures of inferior alveolar nerve transposition in 98 patients were performed over a period of 10 years with 379 dental implants inserted in one stage with the procedure. Patients were examined every 2 weeks. The inferior alveolar nerve function was evaluated with various sensory tests. Panoramic radiographs were obtained immediately, at 3 months, and at 1 year after the surgery. The patients received implant-supported fixed prostheses after 3 to 5 months. Results: The healing process was uneventful in 96 patients; however, in two patients (1.5%) spontaneous fracture of the treated site was observed 3 and 4 weeks postoperatively. The fractures lines occurred at a failed implant site. Both cases were treated conservatively. Conclusions: Spontaneous fractures following inferior alveolar nerve transposition are an important but rare complication. Conservative treatment modalities might be useful and indicated in some of those cases. Keywords: atrophic mandible, implant complications, inferior alveolar nerve, mandibular fracture