下颌骨缺损个体化修复体的应力分析与优化设计**☆

背景：采用钛网支架整复下颌骨缺损常因设计不合理、固定不当造成修复体松脱甚至折断导致失败。 目的：针对一侧髁状突的下颌骨缺损，探讨使下颌骨断端和修复体应力分布合理的最佳设计方案和固定方式。 方法：建立下颌骨断端的简易三维模型和三种修复体模型，模拟咀嚼运动，施加垂直方向载荷，进行有限元法应力分析。 结果与结论：3种设计方案中，延伸板形态与下颌骨外形一致并包绕下颌骨下缘，并在下颌骨下缘增加固定螺钉的设计，在负荷时修复体变形最小，下颌骨断端及固定螺钉受力也最小。提示在单端固定式下颌骨修复体的设计中，应将延伸板形态设计为与下颌骨外形一致且包绕下颌骨下缘，并有必要增加下颌骨下缘处的固定。

Stress analysis and optimization design of titanium framework for repair of individual mandibular defects

BACKGROUND: With the development of research in the field of bone substitute in recent years, more and more cases of mandibular bone defects were treated with titanium frameworks in plastic surgery. The titanium frameworks became loosen and broken in even worse cases due to unreasonable design and fixation. Therefore stress analysis and structure design and nice fixation were the key to this problem. OBJECTIVE: To analyze the stress and strain on titanium framework, stump of mandible and fixing screws in load when the defect area includes unilateral condyle. METHODS: The three-dimensional finite element models of defective mandible and three types of titanium frameworks were established, and then the vertical load were exerted to simulate the mastication movement. Finally, stress and strain situation of different design were analyzed. RESULTS AND CONCLUSION: Among the three types of frameworks, the one whose contour of extend plate was smooth and continuous with mandible and overcoated the inferior border of mandible got the minimum stress on stump and fixing screw, furthermore the framework got the least distortion. In design of titanium framework fixed unilaterally to repair the mandible bone defects including a condyle, the extend plate should be smooth and continuous with mandible and overcoat the inferior border, moreover, stronger fixation in inferior border of mandible is necessary.