基于体素的牙种植体及颌骨的有限元建模

目的 为开发包含应力分析的牙种植PISA软件系统搭建有限元自动建模平台。方法 首先利用VTK技术由患者的CT图像建立3D实体模型并进行可视化；然后根据颌骨特点进行种植体的选型、定位并重新采样；最后通过将体素转换为8节点的正六面体单元来建立有限元几何模型；骨组织的材料属性值由节点的灰度值直接计算得到。结果 针对目前临床应用最多的骨内种植体，建立了适合牙种植体及颌骨特点的基于体素的有限元自动建模方法，能在几分钟内得到准确反映患者个体真实几何信息和骨材料状态的体素有限元模型。结论 本文建立的方法使得在临床利用有限元应力分析对种植牙手术进行术前预测、评价成为可能。该方法也可用于微结构的有限元建模。

A Novel System for Constructing Voxel-based Finite Element (FE)Models of Dental Implant and Jawbone

Objective To develop a new method for constructing a voxel-based finite element (FE) model of implant-jawbone structure automatically for each individual patient, so that it can be integrated into current PISA (Personalized Implants and Surgical Aids) system to improve the design of dental implant surgery. Mothod CT images were preprocessed with a self-designed software, and 3D solid model was created and visualized basing on VTK technology; after that, implants were selected and positioned into the jawbone interactively according to 4 critera, finally the 3D FE model was created automatically by converting each voxel to an 8-nodes hexahedral elements. Bone material mechanical properties were calculated from the gray value of nodes directly.Result A new method was provided to create voxel-based FE models of jawbone-implant structure. It could be used to create FE model including precise geometry information and bone material properties in a few minutes for individual patient.Conclusion The method presented is fully automatic, and can be used to help dentist in predicting the biomechanical performance of dental implant surgery planning in clinic. It can also be used in the Micro-FEA research on bone remodeling around dental implant.