下颌第一磨牙面磨耗近中根受力影响的三维有限元分析  

Three dimensional finite element analysis of the influence of stress on occlusal surface of the mandibular first molar

作　　者：高国宁[1] 王国友[1] 宋继武[1] 卢守仪[1] 

机构地区：[1]潍坊市人民医院口腔科,山东潍坊261041

出　　处：《上海口腔医学》2016年第2期162-167,共6页Shanghai Journal of Stomatology

基　　金：潍坊市卫生局立项课题

摘　　要：目的 :采用三维有限元技术,分析下颌第一磨牙在面水平磨耗与倾斜磨耗2种情况下受力时,其牙体内的应力分布和瞬间位移情况,探讨近中根纵裂发生的生物力学依据。方法:运用Mimics有限元软件建立下颌第一恒磨牙三维有限元模型,分为无磨耗组(对照组)、水平磨耗组(实验组1)和倾斜磨耗组(实验组2)3组,实验组1和实验组2再根据4种磨耗程度,分别建立平切1、平切2、平切3、平切4和斜切5°、斜切10°、斜切15°与斜切20°8种研究模型。经面加载200 N的咬合力,运用MSC.Marc非线性有限元分析软件分析各种状态下模型内的等效应力和瞬间位移,分析牙根纵折发生的生物力学依据。结果:1无磨耗组第一磨牙应力主要集中在面中央窝沟处,位移等值线主要集中在牙冠近中偏颊面,向下延伸至牙颈部。2水平磨耗组应力主要集中于牙冠部及近远中根的根分叉水平,位移等值线整体逐渐偏向面近中偏颊侧牙颈部区域,类似于楔状缺损的V型。3在倾斜磨耗组,当磨耗平面向远中倾斜角度由5°增至15°时,瞬间位移等值线与牙长轴交角变小,近中根所受剪切力最大,产生的应力集中,发生牙根纵裂的可能性增大;当倾斜角度增大至20°时,应力主要集中在牙冠部,其位移等值线呈环形,最大位移出现在牙冠内。提示临床上当牙冠磨耗严重、牙尖斜面明显倾斜时,倾斜牙尖成为应力集中区,易发生折裂。结论:下颌第一磨牙面磨耗面向远中倾斜时,其近中根发生纵裂的可能性较大,为临床上预防性调磨过度磨耗的下颌第一磨牙,降低近中根纵裂的可能性提供了生物力学依据。PURPOSE： Use of three-dimensional finite element to analyze stress distribution and transient displacement of mandibular first molar both at the occlusal surface level, to investigate the biomechanical basis of vertical root fracture occurring in the mesial root. METHODS： Mimics finite element software was used to build the horizontal and tilt abrasion of the mandibular first permanent molar. Each status was then divided into 4 kinds of wearing degree and 8 models were then established including sliced 1, sliced 2, sliced 3, sliced 4 and miter 5°,miter 10°,miter 15°,miter 20° respectively. 200 N of bite force was loaded on the occlusal surface using MSC. Marc nonlinear finite element analysis software was used to investigate the distribution of stress and transient displacement. RESULTS： When distal tipping angle of the abrasion plane of mandibular first molar increased from 5° to 15°, the angle between instant displacement contours and tooth long axis become smaller, the mesial root suffered from the biggest stress concentration and thus the possibility of longitudinal root fracture increased. CONCLUSIONS： When the abrasion plane of mandibular first molar tilted distally, the possibility of the mesial root longitudinal fracture increased.

关 键 词：下颌第一磨牙 近中根 磨耗 三维有限元 等效应力 瞬间位移 

分 类 号：R781.05[医药卫生—口腔医学]