单侧加载对髁突表面应力影响的三维有限元研究

Three-dimensional finite element analysis of stress distribution by unilateral loading on condyle

目的:用三维有限元法探讨下颌单侧加载时对髁突表面应力分布的影响,以期为临床提供有益的参考。方法:利用所建的下颌骨三维有限元模型,约束模型颞骨区上表面全部节点的自由度,限制下颌运动;约束后牙咬合面节点和垂直方向的自由度。分别观察单侧(右)第二磨牙区和双侧第二磨牙区加载时,两侧髁状突表面22个区域应力分布变化情况。结果:双侧加载时在髁突表面产生的负荷,左右侧分布对称;单侧加载时,两侧髁状突表面应力分布不对称:工作侧髁突承受的最大拉应力大于非工作侧,而非工作侧髁突表面的最大压应力大于工作侧,非工作侧所有区域的VonMises应力和最小主应力均大于工作侧。结论:单侧加载可造成双侧髁突表面应力不对称改变,非工作侧髁突表面产生的负荷大于工作侧,提示临床下颌单侧受力可能是颞下颌关节紊乱综合病的病因之一。

Objective： To investigate the effect of unilateral occlusal loading on the surfaces stress of condyle by three-dimensional finite element analysis. Methods： On the basis of three dimensional fmite element model of mandible, condyle surfaces stress changes were observed under unilateral （rigt） and bilateral occlusal loading. Result： When the model loaded with bilateral location, the stress was equal on the bilateral condyle surfaces. When the model loaded with unilateral location, the maximum tension stress was larger on the working side than that on the non-working side, but the maximum compressive stress was larger on the non-working side than that on the working side, and the minimum principal stress and Von Mises stress on the non-working side were larger than that on the working side. Conclusion： The bilateral condyle surfaces stress will occur changes when unilateral occlusal loading, which might be one of the etiologic factor of temporomandibular joint disorders.