Mandibular fracture caused by peri-implant bone loss: report of a case

BACKGROUND: A major complication related to excessive bone loss around implants is fracture of the mandible. This complication is most likely to occur in a very atrophic mandible. A 57-year-old woman presented with progressive pain and swelling that had been present for 5 days in the right frontal region of the mandible. An intraoral radiograph revealed a radiolucency around one of the implants in the interforaminal region. METHODS: Ten years earlier, 4 hollow-screw implants of 10 mm length had been inserted in the interforaminal region of the edentulous mandible. Throughout the 10-year postoperative period, no adverse clinical events were seen; however, during the last 7 years, no radiographic follow-up was performed. Mobility was tested after removal of the bar, on which one of the implants appeared to be mobile. The mobile implant was removed together with the fibrous tissue. RESULTS: At a recall visit 2 weeks later, a radiograph revealed a fracture of the mandible at the explantation site. Characteristic features of the hollow-screw implant are the hollow body and the transverse openings in the side walls of the implant. It has been reported that these characteristic features can enhance infection and rapid bone loss, but a case of mandibular fracture has never been described. CONCLUSION: Radiographs should be taken on a regular and perhaps more frequent basis to diagnose excessive bone loss, so that measures can be taken to prevent the risk of mandibular fracture.