[Bidirectional and unidirectional distraction of defects of the alveolar process comparative clinical study]

Bone resorption and complications in alveolar distraction osteogenesis

Distraction osteogenesis presents an alternative procedure for augmentation of atrophic alveolar bone prior to inserting dental implants. The aim of this retrospective study was to evaluate complications of this method with specific focus on bone resorption during the consolidation period and the follow-up period after dental implant insertion into distracted bone. Thirty partially edentulous patients underwent a total of 36 vertical alveolar distractions with an extraosseous distraction system. Eleven devices were placed in the maxilla and 25 in the mandible. Eighty-two dental implants were inserted after a mean consolidation period of 4.5 months. Treatment results were evaluated by means of panoramic radiographs for distraction follow-up and periapical radiographs for implant follow-up. The mean length of the transport segment was 19 mm. The average alveolar height achieved was 6.4 mm with a mean resorption of 1.8 mm (21.1%) at the time of dental implant insertion. Main problems comprised oral displacement of the transport segment (n = 15) and inadequate soft tissue extension (n = 13). Eighty-two dental implants were inserted with an overall survival rate of 95.1% after 45.8 months. For periimplant marginal bone, an average resorption of 3.5 mm was recorded 50.4 months after implant insertion. Although alveolar distraction osteogenesis seems to be an effective tool to treat vertical defects of the alveolar ridge, it is not an uncomplicated procedure. A combination with vestibular augmentation of autogenous bone grafts should be considered. Overcorrection of 20% may compensate bone relapse during the consolidation period of the distracted alveolar bone. Further bone resorption after dental implantation is common.