上颌第二磨牙应力分布的实验研究

目的研究上颌第二磨牙在不同载荷状态下的应力分布情况，为临床牙体病的诊断与修复提供理论依据。方法采用螺旋CT扫描数据建立上颌第二磨牙的三维有限元模型，在此模型上对4种不同载荷状态下的应力分布进行数据分析。结果模拟正中咬合状态受力时．应力峰值较低，内部应力分布均匀．应力高集中区域分布于牙颈部。非正中咬合状态受力时，其应力峰值明显升高．应力集中区域位于袷面窝沟。结论牙折裂的发生与牙体受力集中于单个牙尖的斜面和近远中向窝沟处有关。

Mechanical Study of the Maxillary Second Molar on Stress Distribution

Objective To study the stress distribution of the maxillary second molar under different loading conditions.Methods A three-dimensional finite element model of the maxillary second molar was constructed by spiral CT scan technology.Based on this model,stress distribution of the tooth under 4 different load patterns was analyzed.Results With loading on the occlusal surface of intact tooth and preparation with centric occlusion,the maximun principal stress was lower and the stress distribution was relatively uniform.Stress on the tooth was stowed to concentrate in the cervical area.When loading on the bevel of tooth,in eccentric occlusion the strength was increased with the increased distribution of stress.Stress on the tooth concentrated in the ditch on the occlusal surface.Conclusion Tooth fracture is related to the excess electric force loading on the bevel of cusps of tooth and ditch from direction on the occlusal surface.