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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牙合面部分。随着粘结剂厚度由50μm增加到140μm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。
Objective: To investigate the effect of different adhesive thickness on the stress distribution of all-ceramic crowns and adhesives with double-layer structure. Methods: Three-dimensional finite element method of three-dimensional finite element method (CT-CT) was used to construct the all-ceramic crowns with double-layer structure (core porcelain and porcelain enamel layer), adhesive layer, dental tissue, root, periodontal ligament and alveolar bone Model, the loading method of vertical concentrated load 600 N was designed and the stress distribution and the stress distribution of core porcelain, porcelain and adhesive layers after different thickness of cement were analyzed. Results: The stress of the core layer mainly concentrated in the porcelain core. The stress of the porcelain layer mainly concentrated near the loading point. The stress of the binder layer mainly concentrated on the mesial buccal shoulder and the palatal side of the palatal face. With the increase of the thickness of the adhesive from 50μm to 140μm, the maximum principal stress located in the porcelain layer, the core porcelain layer and the adhesive layer shows a gradual upward trend. Conclusion: Clinical application of all-ceramic crowns and dental tissues should be ensured as much as possible to reduce the stress distributed on all-ceramic crowns and adhesive layers of double-layer structure and improve the fracture resistance of all-ceramic crowns.