Experimental alveolar ridge augmentation by distraction osteogenesis using a simple device that permits secondary implant placement.

The purpose of this study was to develop an improved technique of alveolar ridge augmentation by distraction osteogenesis using distraction screws, and to investigate tissue reactions to titanium implants at the distraction site. The left mandibular premolars were extracted from 6 adult dogs. After 12 weeks, a box-shaped osteotomy of the alveolar bone was carried out, and distraction devices were placed on the transport and base segments. After a 7-day latency period, the alveolar bone was augmented by 7 mm vertically at a rate of 1.0 mm/day. Just after distraction, these devices were replaced with dental implants for fixation of the transport segment and bone formation of the distraction site. Histologic and radiographic evaluations were made at 8 and 12 weeks after distraction. Vertical augmentation averaged 6.1 mm after 12 weeks of consolidation. It was possible to lengthen the alveolar bone without great difficulty, and good bone formation was recognized in the distraction site. Greater integration between the implant and the distracted bone was observed at 12 weeks after distraction than at 8 weeks. Distraction osteogenesis was successfully applied to alveolar ridge augmentation by this improved technique, and the implants osseointegrated in the augmented ridge.