下颌骨各向异性材质模型对种植牙有限元分析的影响

目的 建立含螺纹种植体各向异性的完整下颌骨有限元模型,研究各向异性材质模型模拟对牙种植体有限元分析的影响.方法 采用薄层CT扫描和自主开发的软件分别建立各向异性和等效各向同性的完整下颌骨三维有限元模型,其中在后牙区植入两枚牙种植体,分析在颊舌向、斜向加载时,种植体-骨界面主应力和主应变值的变化.结果 在各向异性下颌骨模型中,除骨皮质第一最小主应力减小6.3%～7.6%和骨松质第三最小主应力减小8.7%～46.0%外,骨界面绝大多数主应力和所有主应变值均大于各向同性;骨皮质主应力增加2.1%～74.1%,主应变增加4.7%～57.3%;骨松质主应力增加10.3%～71.4%,主应变值增加19.5%～63.4%,而且骨松质应力的增加比骨皮质明显.结论 下颌骨种植牙有限元分析时,下颌骨各向异性模拟会明显影响骨界面应力和应变值,并以增加为主.在生物力学研究中应更注重下颌骨各向异性的材质力学特性.

Three dimension finite element analysis of anisotropic mandible with dental implants effect on implant-bone interface

Objective To establish anisotropic mandible model with dental implants and to investigate the effect of anisotropy material on stress and strain distribution of implant-bone interface.Methods Three-dimensional finite element models of whole mandible with anisotropic and equivalent isotropic material were created by CT scanning and universal surgical integration system(USIS)software developed by the authors.Two ITI threaded implants were implanted in the posterior teeth area.The vslues of principal stress and principal strain on the bone around dental implants were calculated in two different finite element madels with buccolingual load.Results In the anisotropic madible model,nearly all values of the principal stress and principal strain on cortical and cancellous bone increased compared with the equivalent isotropy model,2.1%-174.1%for principal stress and 4.7%-57.3%for principal strain,but 10.3%-71.4%for principal stress and 19.5%-63.4%for principal strain on cancellous bone.Conclusions In the three-dimensional finite element analysis,anisotropic mandible model with dental implants has an apparent effect on the stress and strains of the implant-bone interface.Anisotropic mechanical properties of mandible should be emphasized in biomechanical study.