牵张方向对下颌骨体部牵张成骨应力分布与位移的影响

Stress distribution and displacement by different distract directions on mandibu lar corpus

目的:研究牵张方向对下颌骨体部牵张成骨的影响。方法:建立下颌骨牵张成骨三维有限元模型,在下颌骨体部模拟牵张成骨,测量不同加载条件下,下颌骨的VonMises应力、颏顶点和右侧下颌角点的位移。结果:应力、位移量与加载力值成线性关系。应力集中在加载部位,双侧加载、与牙合平面平行方向加载时,VonMises应力更大,颏顶点、下颌角点表现为X、Z轴向的正位移和Y轴向的负位移;与下颌骨下缘平行方向的加载应力小,颏顶点、下颌角点表现为X、Y轴向的正位移和Z轴向的负位移。结论:单侧加载时下颌骨向对侧偏斜多,双侧加载时矢状向位移趋势大。与上颌牙合平面平行的加载较与下颌骨体下缘平行的加载应力大,但不会造成前牙开牙合。

Objective: To study stress distribution and displacement by different distract directioos on mandibular corpus with finite element method. Methods:A three-dimensional finite element model of mandibular distraction osteogenesis was established.Von Mises stress as well as the displac ement of gnathion and gonion under different loads were measured. Result s:The stress and displacement were positively related with distract forc e. Von Mises stress primarily accumulated in distracted areas and were higher un der bilateral distraction parallel to the occlusial plane. Gnathion and gonion w ere positively displaced on X and Z axes and negatively displaced on Y axis. Distraction parallel to the mandibular body induced positive displaceme nt of mandible on X and Y axes and negative on Z axis. Concl usion:Transversal displacement to the opposite side is greater during un ilateral distraction, while displacement on the saggittal plane is greater durin g bilateral distraction.