前牙烤瓷冠牙体预备颈缘形态与应力的三维有限元分析

Three dimensionlal finite element analysis of margin configurations and stresses of procelain fused to metal crowns

作者采用三维有限元法，对唇测颌绿三种形态设计的烤瓷冠，在承受不同方向力时，颈缘瓷体的应力变化进行分析。结果：唇侧颈缘凹型设计拉应力比肩台型和斜面肩台型者小；凹型颈缘形态金属与瓷体的应力差值小；冠的切缘受唇向外力时，唇侧颈缘担应力较大。该实验为以下两结论提供了力学依据，即颈缘设计凹型优于肩台型和斜面肩台型；烤瓷冠受唇向外力易引起瓷面折裂。

As to using the method of three dimensional finite element,this study hasanalyzed the stress distribution of the porcelain fused to metal crowns with three differentlabial margin configurations under the f0oces fr0m diverse directi0os. T The results showed thatthe chamber margins exhibited fewer tensole streoses than the sh0uoder 0r shoulder with a bev-el margins. The labial margin exhibited more tensil stresses when the incisal edge of the crownwas loaded with labial forces. so,we provide the mechanical basis for the conclusions as fol-lows: (1)The labial chamber margin is preferable to sh0ulder or shoulder with a bevel margin. (2)The porcelain may fracture when the incisal edge of porcelain fused to metal crown.isloaded with labial forces.