[Mandibular fractures due to implant management--incidence, mechanism of injury and therapeutic characteristics].

We report of 5 of 337 patients (1.48%), in whom a fracture of the edentulous atrophied mandible occurred after dental implants had been inserted. In 79 patients a sandwich osteotomy (anterior and/or lateral mandible) had been carried out together with the insertion of implants. The reason for a fracture was infection in 3 patients and weakening of the atrophied mandible by the additional osteotomies in 2 patients. One of the latter two was seen intraoperatively and fixed immediately using miniplates. The other occurred about 4 weeks postoperatively and was not discovered until callus had been developed. Consequently only 4 of the 5 patients were treated by osteosynthesis. In two patients no implants were lost. The application of bone morphogenetic protein (BMP) helped to avoid the loss of implants because it accelerated ossification of the fracture and the integration of the implants.