摘要
目的 用三维有限元方法分析前牵引颏部反作用力对颌骨尤其是颞下颌关节应力及位移的影响,为前牵引的临床应用提供参考.方法 选择1名健康男性青年志愿者作为研究对象,对其头部行CT扫描,并借助Mimics等专用软件,建立完整的颅颌面三维有限元模型.根据前牵引矫治器反作用力原理,直接在颏部中央的最下方施加与（牙合）平面成后上22°～49°（每隔3°取1个角度）的载荷,大小为5N,测定颌骨尤其是颞下颌关节的应力及位移变化.结果 在不同角度施加相同载荷时,上颌骨产生接触应力,加载角度由22°增大到40°时,颞下颌关节窝内应力逐渐下降,加载角度由40°增大至49°时,颞下颌关节窝内应力略有增大;下颌骨同样产生接触应力,髁突头应力随加载角度增大而减小（由0.405 MPa减小至0.037 MPa）,髁突颈部随加载角度的增大呈先降后增的趋势.载荷与（牙合）平面呈后上40°时颞下颌关节区受力最小（0.018 ～0.327 MPa）.三维有限元模型上各节点X轴位移均为正值,且随加载角度增大而减小;Y轴位移出现负值,从40°开始变为正值,即载荷加载角度小于40°时下颌骨发生后下旋转.载荷与（牙合）平面呈40°时颞下颌关节区位移值较小（0.0005 ～0.0081 mm）.结论 前牵引矫治作用于颏部的反作用力在与（牙合）平面成后上40°时传导至颞下颌关节区的应力值和位移值均较小,有利于关节组织的健康.
Objective To analyze the influence of different reactive force direction of protractions on temporomandibular joint （TMJ） by establishing a three-dimensional finite element model （FEM） of craniomaxillofacial complex.Methods The CT image of the head of a healthy young male volunteer was obtained.With the help of Mimics software,we established a three-dimensional finite element model of craniomaxillofacial complex which included TMJ.The force pattern of maxillary protraction appliance was imitated.The force（5 N） was applied on the chin and the direction of force was from 22° to 49° relative to the occlusal plane.The displacement and stress distribution of TMJ were analyzed.Results The contact stress on the maxilla decreased with the angle of the force direction increased from 22° to 40°,and increased with the angle increased from 40° to 49°.The stress on the condyle decreased with the angle of the force direction increased.The stress on the condylar neck decreased initially and then increased with the angle of the force direction increased.Comprehensively,the stress was the smallest when the angle of the force direction was 40°.The clockwise rotation of the mandible was found when the angle of the force direction was smaller than 40°.The displacement value was relatively small when the angle was 40°.Conclusions Stress and displacement were relatively small when the angle of the force direction was 40° relative to the occlusal plane.
出处
《中华口腔医学杂志》
CAS
CSCD
北大核心
2013年第12期740-744,共5页
Chinese Journal of Stomatology
基金
山东省自然科学基金（ZR2011HM036）
山东省医药卫生科技发展计划（2011QZ023）
关键词
颞下颌关节
有限元分析
口外牵引器
Temporomandibular joint
Finite element analysis
Extraoral traction appliances
