目的研究在Forsus矫治力作用下的下颌髁突的应力-第三军医大学学报.doc

Forsus矫治力前导下颌有限元仿真及最佳施力角度探讨( 颜功兴 刘占芳 摘 要: 目的 研究在Forsus矫治力作用下下颌骨的应力分布情况和位移情况，探讨最佳的施力角度为临床应用提供生物力学基础。 选择临床恒牙牙合安氏Ⅱ类远中错牙合志愿者，运用螺旋CT扫描技术及三维影像技术完成初步重建并在此基础上利用Abaqus 软件建立下颌骨牙列和弓丝的三维有限元模型 在5种工况下，弓丝托槽和牙列上的Von Mises等效应力水平相对于下颌骨较高，最大应力出现在弓丝托槽。下颌骨上的应力集中主要位于髁突颈和牙槽嵴部位，下颌骨上最大的Von Mises等效应力出现在髁突颈处，下颌骨最大的位移都基本出现在颏部，髁突颈局部发生了塑性变形。 Forsus矫治力的加载角度最好0°～25°。 关键词下颌骨；有限元模型；生物力学 FEM analysis on submaxilla anterior guidance subjected to forsus orthopedic force and discussion on optimal angle of orthopedic force YAN Gong-xing, Liu Zhan-fang (Department of engineering mechanics, Chongqing university, Chongqing 400030) 【Abstract】 (1)Objective To research the stress and displacement distribution of submaxilla subjected to forsus orthopedic force，and to discuss the optimal angle of orthopedic force. It can provide biomechanical basis for clinical application. (2)Methods Take clinical volunteer with Angle classⅡ malocclusion, and helical CT and 3-D image technique were used to finish the primary model reconstruction. On the basis of scanned skull image , Abaqus software is used to construct a 3-D FE model of forsus-dent-submaxilla. (3)Results Under all five loading conditions, the Von Mises equivalent stresses level on forsus-dent are higher than on the submaxilla, the highest stress is on the forsus. Stress centralization on submaxilla mostly locates at condylar and alveolar ridge, the highest stress of submaxilla is on the condylar, and the largest displacement of submaxilla is on the chin basically. And plastical strain were appeared on the condylar. (4)Conclusion The optimal angle of orthopedic forsus force is between 0° and 25°. 【key words】Submaxilla; FEM model; Biomechanics Ⅱ类错牙合是临床常见的错牙合畸形之一，下颌后缩是II类错牙合畸形的重要特征之一，青少年Ⅱ类错牙合畸形中下颌后缩占46％[1]。下颌后缩畸形严重影响患者的颜貌和功能，根据畸形性质、程度和形成机制，在不同时期应用功能矫治器进行下颌前导是矫治的关键之一。一直以来，人们试图应用各种试验和计算力学方法对下颌前导过程进行研究，随着口腔医学和力学的交叉和进步，有限元法（Finite Element Method，简称为FEM）在口腔生物力学中得到了广泛应用，对矫治过程的有限元数值仿真能更好地指导临床。2002年马轩祥等[24]采用FEM方法建立了下颌骨、TMJ和关节盘的几何相似性模型分析了其不同加载下的应力分布，该有限元模型基于牙齿和