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目的:基于有限元数值计算方法探讨不同基底瓷厚度对IPS e.max press全瓷冠应力的影响。方法:建立下颌第一磨牙形态试件,基底瓷厚度分别为0.30 mm、0.50 mm、0.75 mm、1.00 mm、1.20 mm五组全瓷冠轴对称的有限元模型,模拟最大咬合力600 N垂直加载于半球形加载头,得出全瓷冠应力分布状态。结果:五组模型应力分布区域相似,全瓷冠最大主应力峰值均位于基底瓷层内,主要集中在加载区下方邻接粘结剂的基底瓷处;饰面瓷的最大主应力峰值主要集中在饰面瓷咬合面与半球形加载头接触的外侧周围;基牙及粘结剂最大主应力峰值均集中在肩台处。全瓷冠压应力峰值主要集中在加载区下方与半球形加载头接触的饰面瓷区域;IPS e.max press全瓷冠的基底瓷厚度对全瓷冠、基底瓷、饰面瓷、基牙及粘结剂的最大主应力均有影响。结论:IPS e.max press全瓷冠在正常咬合力作用下,可以在满足美观的基础上,尽量增加基底瓷厚度,以期增加全瓷冠整体断裂强度,提高使用寿命。
OBJECTIVE: To investigate the effect of different porcelain base thickness on the stress of IPS e.max press all-ceramic crown based on the finite element method. Methods: The mandibular first molars specimens were prepared and the base porcelain thicknesses were 0.30 mm, 0.50 mm, 0.75 mm, 1.00 mm and 1.20 mm, respectively. In the hemispherical loading head, obtained all-ceramic crown stress distribution. Results: The stress distributions of the five models are similar, and the maximum principal stress peaks of the all-ceramic crowns are all located in the basement porcelain layer, mainly concentrated in the base porcelain of the adjacent adhesive below the loading area. The peak of the maximum principal stress of veneer porcelain is mainly concentrated in The facing porcelain occlusal surface and the hemispherical loading head contact around the outside; the maximum principal stress peak of the abutment and the adhesive are concentrated at the shoulder. All ceramic crown compressive stress peak concentrated in the loading area below the hemispherical loading head contact veneer porcelain area; IPS e.max press all porcelain crown base porcelain crown on the all-ceramic crown, base porcelain, veneer porcelain, abutment And the maximum principal stress of the binder have an impact. Conclusion: Under normal occlusal force, IPS e.max press all-ceramic crowns can increase the base porcelain thickness as much as possible while satisfying the esthetic appearance, in order to increase the fracture strength of the whole porcelain crowns and improve the service life.