摘要目的 用三维有限元法对两种桥体设计的金沉积基底冠熔结镍铬桥体烤瓷桥进行应力分析,以期为烤瓷桥的临床修复设计提供参考.方法 建立两种金沉积基底冠熔结镍铬桥体烤瓷桥(桥体固位部分分别设计为半包型和环状型)的三维有限元模型,分别在桥体袷面中央窝轴向加载200 N垂直载荷和从桥体颊(牙合)边缘嵴中央指向舌侧、与(牙合)平面成30°角方向加载400 N侧方载荷,分析两种模型的应力分布.结果 两种烤瓷桥的应力分布基本相似,最大主应力集中区主要位于远中连接体.垂直加载时,半包型和环状型镍铬桥体的最大主应力分别为24.17 MPa和24.85 MPa;侧方加载时,两者最大主应力分别为42.83 MPa和42.69 MPa.垂直加载时和侧方加载时,金沉积基底冠的边缘区为最大主应力区.结论 金沉积基底冠熔结镍铬桥体烤瓷桥的应力集中于连接体,金沉积基底冠边缘是薄弱区.

abstractsObjective To analyze stress distribution of two framework designs in compound galvanoceramic bridges made with three-dimensional finite element models. Methods Three-dimensional finite element models were developed for compound galvano-ceramic bridges with two designed retainers of Ni-Cr frameworks which ringed or partially covered the electroformed gold caps. The models were vertically loaded 200 N on the center of the occlusal surface of the pentic and loaded 400 N on the center of buccoclusal marginal ridge from buccal aspect to lingual aspect at a 30° angle with the occlusion plane respectively. The stress distributions and the level of stress concentration in the two models were analyzed by the FEA software. Results Stress distributing in two designed framework of compound galvano-ceramic bridges were similar. The highest von Mises stress of compound galvano-ceramic bridges was concentrated in the distal connector of the pontic and retainer. Under the vertical loading, the von Mises stress was 24.17 MPa for the partial cover retainer of the Ni-Cr framework and 24.85 MPa for the circular retainer. Under the lateral loading, the corresponding figures were 42.83 MPa and 42.69 MPa, No matter vertical or lateral loading,the margin of electroformed cap was the concentration area of the yon Miese stress. Conclusions In this study, the stress concentration area of compound galvano-ceramic bridges with Ni-Cr framework and electroformed gold caps was the connector and the margin of electroformed cap was the unsubstantial area.