The use of intra-osseous versus extra-osseous distraction devices in atrophic mandibles.

To allow for implant placement in severe atrophic edentulous mandibles, distraction osteogenesis can be used to gain sufficient bone height. The efficacy of extra-osseous and intra-osseous devices is evaluated. In this retrospective study, 45 patients treated with an extra-osseous device (EOD) were compared with 43 patients treated with an intra-osseous device (IOD). From a statistical point of view, both patient groups were comparable for age and sex ratio. The IOD group gained more bone height (9.8 mm) than the EOD group (6.0mm). A significantly higher degree of backward tilting of the device was observed in the EOD group (12.1°), compared with the IOD group (3.0°). There were also significantly more fractures of the basal bone segment and sensory disturbances of the chin area in the EOD group than in the IOD group. The IOD group scored significantly better on bone height gained, backward tilting of the device, occurrence of fractures, and postoperative sensory disturbances. Despite the fact that the mean preoperative bone height for the IOD group was substantially higher (18.6mm) than for the EOD group (11.9 mm), it may be concluded that for augmentation procedures of the edentulous mandible, the IOD is more favourable.