下颌骨缺损自体骨移植重建的生物力学研究

模拟临床下颌骨缺损状态和咬合力学环境,对自体骨移植重建下颌骨的生物力学效果进行分析、评价。根据人体骨骼和肌肉系统的解剖学特征,模拟B、BS＇＇S”和RB＇＇S”类缺损状态,建立腓骨和髂骨修复下颌骨三维有限元模型,对咬合力作用下重建下颌骨的应力状态进行了分析。结果表明,不同缺损腓骨重建,从右侧后牙牙槽嵴对应接骨处到左侧颏部对应接骨处,应力状态均从压应力到拉应力过渡．应力值大小受缺损方式影响;相同缺损腓骨与髂骨重建,以皮质骨为主要成分的腓骨重建下颌骨,应力分布较完整下颌骨有显著变化,移植骨上最大应力约为正常骨上5倍,呈现明显的应力遮挡;以松质骨为主要成分的髂骨重建下颌骨,应力状态和完整下颌骨基本相同。因此,髂骨重建下颌骨的力学性能较腓骨类更接近完整下颌骨．更利于术后愈合和进一步的功能重建。

Study of Biomechanical Effects on the Reconstruction of Mandible Defect with Autogenous Bone Grafts

The biomechanical effects of the reconstructed mandible with autogenous bone grafts were analyzed and evaluated, under simulated mechanical environment of occlusion. Based on anatomical feature of the human skeleton, muscle system and the clinical B, BS"S" and RB"S"defect patterns, the modularized model of mandible and the three finite element models of the fibula grafts and iliac crest grafts reconstruction mandible were made. The stress state calculations under bite force were also processed. The findings are as follows: Along the right connection area to left connection area (corresponding to far-end of the molar teeth alveolar ridge and the chin section respectively), the stress state on the various grafted bone all changes from compression stress to tensile stress. There is obvious change on the stress distribution between the fibula type reconstruction mandible and normal one. The stress on the grafted bone which is mainly made up of cortical bone is approximately 5 times higher than that of normal, which indicates the obvious stress shielding effect; the stress distribution of the iliac crest type reconstruction mandible is close to the normal mandible, the iliac crest used is mainly made up of cancellous. Therefore, the mechanical properties of the reconstructed mandible with iliac crest are more similar to normal mandible, which is beneficial to wound healing and further functional reconstruction.