下颌骨牵引延长过程中器械的应用与拆除时机

目的：确定下颌骨骨牵引引延长过程中器械应用与拆除时机，为临床应用提供参数。方法：采用自制的ＭＳ－１型内置式下颌骨骨牵引延长器行犬下颌骨牵引引延长；取新成骨，制成标准骨生物力学测试件，进行轴向压缩及三点弯曲实验；测量新成骨的弯曲强度、抗压强度、弹性模量、泊松比等特征材料参数，并与对照组分别比较。结果：新成骨在牵引引完成后３周时分别达到对照组的３７％～６０％，５周时各参数值分别达到正常对照组的８９％～

The removing time for distraction of osteogenesis device on mandibular lengthening process

To measure the biomechanical property of the new bone generated by mandible lengthening with a self-made internal distraction osteogenesis (DO) device. Methods: DO device was applied in dogs to elongate the mandible. Three-point bending and compress tests were conducted on standard new bone specimens 3 and 5 weeks after operation. The indexes of ultimate load, stress, elastic module and possion ratio of the specimens were measured. Results: The ultimate stress of the new bone approached 37%-60% and 89%-95% of that of the normal mandible controls 3 and 5 weeks after operation respectively. Conclusion: The DO device could be removed after 4-5 weeks of consolidation during the distraction osteogenesis of mandible lengthening.