有限元法分析不同粘结剂厚度对全瓷冠应力分布的影响

目的：探讨不同粘结剂厚度对双层结构的全瓷冠及粘结剂应力分布的影响.方法：利用螺旋CT断层图像,构建双层结构的全瓷冠（核瓷层和饰瓷层）,粘结剂层,牙体组织,牙根,牙周膜,牙槽骨各部分的三维有限元模型,设计垂直集中载荷600 N的加载方式,分析不同厚度的粘结剂粘固后核瓷层、饰瓷层及粘结剂层的应力大小及分布状况.结果;核瓷层应力主要集中在核瓷内部,饰瓷层应力主要集中在加载点附近,粘结剂层应力主要集中在近中颊侧肩台和腭侧面近殆面部分.随着粘结剂厚度由50 μm增加到140 μm时,位于饰瓷层、核瓷层和粘结剂层的最大主应力呈现逐渐上升的趋势.结论：临床上应尽量保证全瓷冠与牙体组织的贴合,以减小分布在双层结构全瓷冠和粘结层上的应力,提高全瓷冠的抗折能力.

Three-dimension finite element analysis on stress of All-ceramic crown of different thickness of agglomerant applications

Objective：To investigate the relationship between the different thickness of agglomerant and stress distribution of All-ceramic crown and agglomerant,and provide the basis for the design of clinical repair.Method：The fault images of spiral CT were used to construct the finite element analysis mode,the model is separated into six parts：crown （include the core layer and the veneer layer）,agglomerant,prepared tooth,the root of the tooth,periodontal ligament,and alveolar bone,and load way was designed：600 N load was vertically concentrated,and ANSYS software was used to analyze the stress values of the core layer、the veneer layer and the agglomerant layer on different thickness of agglomerant.Result：The stress of the layer lies in the positions of the mesio-buccal shoulder and the teeth near occlusal surface from the lingual side; the stress of the core layer located in the inner surface from the colossal side; the stress loads in the veneer layer is applied on the location where the load applied.When the thickness of the agglomerant grows from 50 μm to 140 μm,the maximum principal stress also attends to a rise in the core layer,the venner layer and the agglomerant layer.Conclusion：Dentists should try to guarantee the accuracy of the ceramic crowns,in order to minimize the maximum principal stress on the double-layered ceramic crowns,which also leads to the improvement of the quality of fracture resistance.