Objective To study the changes of bone mineral density during trifocal mandibular distraction os-teogenesis. Methods 4 monkeys were used in this study. The mandibular symphyseal defects were made by resection of the anterior part (ranged from canine to canine) of mandible. Bilateral transport disks (ranged from first premolar to first molar) were created in the remaining mandibular bodies, and a custom-made adjustable mul-tiplanar distraction apparatus was applied to repair the artificial mandibular symphyseal defects by means of tri-focal distraction osteogenesis. After a delay period of 7 days, the bilateral transport discs were distracted forward and inward simultaneously. All monkeys were sacrificed at 16 weeks after the completion of distraction. The di-stracted calluses and normal bone tissue in mandible body were harvested and processed. Their bone mineral density were analyzed by double energy X ray absorptiometry. Results Bone mineral density in distracted calluses showed no statistical significance compared with normal bone tissue in mandible body. Conclusion This study suggests that the bone in distraction area may satisfy the function of mandible biomechanically at 16 weeks after the completion of distraction%目的 研究下颌三焦点牵张成骨整复颏部缺损的牵张区新生骨密度变化.方法 选取4只成年恒河猴,通过下颌前份骨截除术形成颏部订三中联合骨缺损.在两侧下颌体部各制备一个输送盘,并用自行研制的多平面牵张装置使双侧输送盘向前内方向缓慢移动并在颏部正中对接以修复颏部骨缺损.牵张结束后16用处死所有动物.采用双能X线吸收法定量分析并对比牵张成骨区新生骨与非牵张区下颌骨体部正常骨组织的骨密度变化.结果 牵张结束后16周牵张成骨区新生骨与非牵张区下颌骨体部正常骨组织的骨密度差异无显著性.结论 运用三焦点牵张成骨术整复颏部缺损牵张结束后16周牵张成骨区新生骨骨密度接近下颌骨体部正常骨组织,基本满足下颌骨功能需要.
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