儿童“颞下颌关节—下颌骨—颏兜矫治器系统”三维有限元模型的建立

Development of a three-dimensional finite element model of child mandible with chincap

目的 :建立儿童“颞下颌关节—下颌骨—颏兜矫治器系统”的三维正交各向同性有限元模型 ,为模拟研究Ⅲ类错牙合畸形矫形治疗中 ,颏兜作用力在下颌骨的应力分布提供基础条件。方法 :选择一名颏兜矫治的下颌前突儿童患者 ,通过CT扫描及图像处理、节点座标的数字化 ,采用ANSYS 5 .6软件建立“颞下颌关节—下颌骨—颏兜矫治器系统”模型 ,设计、模拟颏兜矫治器后牵引下颌的边界约束条件。结果 :建立了更接近临床实际应用颏兜情况的三维有限元模型 ,并可模拟不同工作状况下模型各部分的力学改变 ,确定了不同后牵引外载荷的加载作用点、方向及大小。结论 :利用CT三维影像重建技术与三维有限元方法结合 ,建立了儿童下颌骨一颏兜三维有限元模型 ,该模型可用于下颌颏兜矫形应力分布研究。

Objective:To build a three-dimensional finite element model of child temporomandibular joint including the mandible with chincap,and provide a basic condition for the study of the effects of chincap on the stress distribution of the base of mandible.Methods:The model was constructed from a child who accepted the treatment of chincap by ANSYS 5.6,using the reconstructive technique of spiral CT in combination with the three-dimensional finite element.The model consisted of 20045 bricks and 4442 nodes.On the model,mandible retraction was simulated under the different traction which included the different directions and magnitudes.Results:Three-dimensional model of the `Temporomandibular joint-mandible-chincap system of child' was established,which was better suited for the actual and practical situation of chincap in clinic,and the loading point and the different directions and magnitudes were determined by clinical application.Mechanical changes of various parts of the model in different working conditions could be simulated by means of adding different material properties and boundary conditions.Conclusion:The established model could be used for the study of stress distribution of chincap applying simulation.