前牵方向逆时针改变反作用力的有限元分析  

A three-dimensional 3-D finite element study on the influence of reactive force when protraction direction changes anticlockwise

作　　者：董瑞[1] 王旭霞[2] 张文娟 陈云[1] 郑德华[1] 张君[1] 

机构地区：[1]山东大学口腔医学院,济南250012 [2]山东大学口腔医学院.山东省口腔生物医学重点实验室 [3]山东省中医药大学附属医院口腔科

出　　处：《现代口腔医学杂志》2013年第6期331-339,共9页Journal of Modern Stomatology

基　　金：山东省自然基金项目(ZR2011HM036);济南市高校院所自主创新计划项目(201202032);山东省医药卫生科技发展计划项目(2011QZ023)

摘　　要：目的建立并使用颅颌面三维有限元模型,分析前牵引角度逆时针减小时其反作用力在颌骨特别是颞下颌关节(TMJ)的应力及位移变化,为正畸临床更好地治疗骨性Ⅲ类错牙合,避免对TMJ的损伤提供实验依据。方法建立完整的包含TMJ的颅颌面三维有限元模型,模拟前牵引矫治器反作用力,直接在颏部施以一定大小的力并逆时针改变施力的方向,测定颌骨和TMJ区应力及位移的变化情况。结果应力方面:①从不同角度加载节点力之后产生最大应力点出现在加载部位颏部,关节窝、髁突头颈部等上下颌接触部位应力也比较集中,且随角度的逆时针变化,最大应力增大;②接触部位(TMJ)应力变化规律:从不同角度施加相同载荷时,上颌骨产生接触应力,角度由37°逆时针减小到22°时,接触应力呈逐渐增大的趋势;下颌骨同样产生接触应力,下颌头处节点的等效应力(如节点24757)随牵引角度的逆时针减小呈增大趋势,下颌颈处的节点(如点24301)也是如此。位移方面:①以一定力值不同角度施加载荷后,该模型产生微小的位移变化,位移最大部位产生在加载部位,下颌骨位移沿X轴正方向逐渐减小。牵引角度小于等于37°时,上颌骨位移沿Y轴由底部到顶部逐渐减小;②5个节点在X,Y方向的位移可以看出:X轴位移值均为正值,且随着角度由37°逆时针减小,位移基本呈上升趋势(31°位移值最小);Y轴位移值大部分为负值(只有37°时关节窝内节点和34°时关节窝内个别节点为正值)说明37°时下颌即发生了后下方(顺时针)旋转,随着角度逆时针减小,上下颌均发生了后下方(顺时针)旋转,且位移值基本呈增大趋势。结论①颅颌面三维有限元模型成功建立;②前牵引矫治器在牵引上颌向前的同时,确实对颌骨及TMJ产生反作用力,如下颌的后下旋转,颏部的应力变形等,因此临床上在保证上颌牵引效果的同时,要考虑将其�Objective To offer a scientific basis on treating Class m malocclusion more well, and avoid injuring TMJ,a three-dimensional finite element model （FEM） of craniomaxillofacial complex is used to analysis the influence of the reactive force on TMJ when protraction direction magnifies clockwise. Methods Establish a complete three- dimensional 3-D finite element model which include TMJ, imitate the force pattern of maxillary protraction, exert a given force on chin, change the direction clockwise , the stress distribution and displacement on jaw and TMJ are analysed. Results Stress distribution： ①The biggest stress points appeared in the loading position chin after loading nodal force from different angle.The stess in the contact region such as the glenoid fossa, condylar head and neck are also relatively concentrated. ②Under the action of different angle, the maxilla produce contact stress. When exert the same size load , the contact stress has a trend of gradual increasewhen the angle change from 37° to22°; under the common action of different angle, the mandible also produce contact stress. In the condition of nodal force equal, the nodes stress of mandibular head and neck showed a trend of increase with angle decrease. Displacement： ①In a certain angle on the nodal force, the model produce tiny displacement change, the largest position displacement produced in loading part,mandible displacement decrease from chin to rear gradually;The maxillary displacement reduced gradually from the bottom to the top when the traction angle is less than 37°; ②The displacement in axis X are all positive, and it increases with the angle increases anticlockwise from 37°; Y displacement in condylar head and neck are negative when 37°,with angle decline both nodes turn to negative ,and it has a trend of increse . Conclusion ①A three-dimensional 3-D finite element model is built successfully; ②Protraction appliance dose produce reactive force on mandible and TMJ when making maxilla forward,so we need think bot

关 键 词：前牵引 方向 反作用力 颞下颌关节 三维有限元 

分 类 号：R783.5[医药卫生—口腔医学]