目的 利用拓扑优化确定最优下颌骨植入物固定板的布局,并设计高承载能力的个性化下颌骨植入物固定板。 方法 以典型的下颌骨缺损模型为例,构建考虑骨骼和支架材料特性的下颌骨有限元模型。 对模型进行拓扑优化分析,设计个性化下颌骨植入物固定板。 通过模拟分析常规固定板系统与个性化固定板系统下颌骨、固定板、 螺钉的应力分布,评估个性化下颌骨植入物固定板的力学特性。 并结合 Gibson-Ashby 模型,设计弹性模量与皮质骨相当的多孔面心立方晶格结构假体,最终确定最终支架方案。 结果 通过安装个性化下颌骨植入物固定板,下颌骨、接骨板、螺钉的峰值应力分别 55. 86、291. 1、122. 53 MPa,分别比安装常规固定板降低 9. 8% 、32. 0% 和14. 6% 。 结合个性化下颌骨植入物固定板与多孔结构的设计方案,得到最优孔隙率为 71. 6% 的三维多孔支架模型。 结论 本研究设计的个性化下颌骨植入物固定板显著降低假体的峰值应力,提高支架的可靠性。 并且结合激光选区熔化(selective laser melting, SLM)技术,可以快速制造出性能优异的个性化假体,以满足紧迫的时间需求。

Objective To determine the optimal layout of mandible implant fixation plates by topological optimization, and design personalized mandible implant fixation plates with high bearing capacity. Methods Taking a typical defected mandible as an example, the finite model of mandible was constructed with consideration of the properties of bone and scaffold materials. Topology optimization analysis of the model was carried out, and personalized mandible implant fixation plate was designed. The stress distributions of the mandible, plate and screw in conventional and personalized plate system were simulated to evaluate mechanical characteristics of personalized mandible implant fixation plate. Combined with Gibson-Ashby model, the porous face-centered cubic lattice structure prosthesis with elastic modulus equivalent to cortical bone was designed, and the final scaffold scheme was finally determined. Results The peak stresses of the mandible, fixation plate and screws of personalized mandible implant fixation plate system were 55.86, 291.1 and 122.53 MPa, respectively, which were 9.8%, 32.0% and 14.6% lower than those of conventional fixation plate fixation system. Combined the personalized mandible implant fixation plate with porous structure, a three-dimensional (3D) porous scaffold model with an optimal porosity of 71.6% was obtained. Conclusions The personalized mandible implant fixation plate designed in this study significantly reduced the peak stress and improved the reliability of the scaffold. Combined with selective laser melting (SLM) technology, personalized prosthesis with excellent properties can be quickly manufactured to meet tight time requirements.

2021 年中国职业技术教育学会项目(2021B161),广东省科技计划项目(2019A050516001)