[Effect of three kinds of modelling of mandible on the finite element analysis of implant].

Objective: To investigate the effect of three types of material homogeneities(isotropy, transverse isotropy, and orthotropy) of mandible on the finite element analysis of implant. Methods: Three-dimensional model of complete mandible containing an implant was constructed and analyzed with isotropic, transversely isotropic, and orthotropic models, respectively. Results: The effective stress, tensile stress, and compressive stress of cortical bone of the orthogonal model were 1.2, 1.2, and 1.1 times larger than that of the isotropic model. The effective stress, tensile stress, and compressive stress of cancellous bone of the orthogonal model were 1.6, 2.6, and 3.3 times larger than that of the isotropic model. The effective strain, tensile strain, and compressive strain of cortical bone of the transversely isotropic model were 1.1, 1.0, and 1.1 times larger than that of the isotropic model. The effective strain, tensile strain, and compressive strain of cortical bone of the orthogonal model were 2.2, 1.8, and 1.7 times larger than that of the isotropic model. The stress and strain of cancellous bone increased when the material homogeneity changed from isotropy to transverse isotropy and to orthotropy. Moreover, in term of stress and strain distribution, the orthotropic modelling of mandible was most uniform followed by the transverse isotropy and the isotropy. Conclusions: In the finite element analysis of implant system, the orthotropic property of the mandible can not be neglected.