输送盘牵张成骨重建下颌髁突的骨密度和力学性能变化

Bone mineral density and biomechanical properties of the neocondyle reconstructed by transport distraction osteogenesis

目的探讨运用输送盘牵张成骨术重建髁突的骨密度和力学性能变化。方法成年山羊16只,截除右侧髁突后运用输送盘牵张成骨术重建髁突,左侧作为正常对照组。牵张结束后24周处死所有动物。采用双能X线吸收法和压缩力学性能测试技术,定量分析并对比两侧髁突的骨密度和压缩力学性能变化。结果手术侧髁突骨密度较正常侧显著升高;其轴向弹性模量和最大应力较正常侧显著升高,横向弹性模量和最大应力两侧无显著性差异,轴向和横向最大应变两侧均无显著性差异。髁突骨松质的力学性能具有明显的各向异性。结论运用输送盘牵张成骨术重建的髁突的骨密度和生物力学性能明显升高;这种适应性改建与颞下颌关节的功能刺激直接相关。

Objective To investigate the changes of bone mineral density and biomechanical properties of the neocondyle reconstructed by transport distraction osteogenesis. Methods Sixteen adult goats were used, and the right mandibular condyles were removed and reconstructed by transport distraction. Their contralateral condyles were served as normal control. At 24 weeks after distraction, compressive mechanical properties and its bone mineral density in bilateral condyles were analyzed quantitatively by compressive mechanical property measurement technique and double energy X ray absorptiometry. Results Bone mineral density in the neocondyle increased significantly compared with that in the normal condyle. In axial loading, the E - modulus and ultimate stress in the neocondyle were higher than those in the normal condyle. In transverse loading, however, no statistical significance was found on the E - modulus or the ultimate stress between bilateral condyles. For both loading directions, no statistical significance was found on the ultimate strain between bilateral condyles. Meanwhile, mechanical properties of the cancerous bone in the condyle were proved to be highly anisotropic. Conclusion This study suggested that bone mineral density and biomechanical properties of the neocondyle reconstructed by transport distraction osteogenesis were significantly increased. This adaptive remodeling in bone structures occurred in the neocondyle may be closely related to the functional stimuli of temporomandibular joint.