Posterior mandibular alveolar distraction osteogenesis utilizing an extraosseous distractor: a prospective study.

BACKGROUND: The aim of this clinical study was to evaluate bone elongation and the effectiveness of distraction osteogenesis when utilizing an extraosseous distractor to treat cases of atrophic posterior mandible.
METHODS: Fourteen surgical sites were evaluated in 10 healthy, non-smoking, female patients, with varying degrees of atrophic posterior mandible, who underwent surgery by alveolar bone distraction. The patients presented between 6 and 10 mm above the mandibular, inferior alveolar nerve. Panoramic radiographs were taken before surgery and at the beginning and end of the consolidation period. The extraosseous distractor was fixed to both the basal and the osteotomized bone. After a 7-day latency period, the patients rotated the distractor rod three times a day for 3 to 10 days (1 mm per day). The mobile segment was held in place for 8 to 12 weeks for bone consolidation.
RESULTS: The results revealed a distraction range of 2.32 to 8.11 mm (mean distraction +/- standard deviation, 5.12 +/- 1.67 mm), which was less than the real, measured distance between the upper and lower miniplates of the distractor (5.58 +/- 1.62 mm). The bone segments showed between 0.03 and 2.53 mm (mean, 0.88 +/- 0.59 mm) resorption above the upper miniplate. The efficacy of the extraosseous distractor was calculated as between 30.41% and 94.58% (73.45% +/- 20.32%).
CONCLUSIONS: Bone regeneration was obtained in all cases; however, when planning alveolar bone distraction using the extraosseous distractor, greater distraction should be performed to compensate for the inclination of the distractor rod and possible bone loss. This adjustment should increase the efficacy of distraction osteogenesis.