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.