后牙全瓷冠不同形态设计的三维有限元分析

目的 分析下颌第一磨牙全瓷冠受载时的应力状况，考察全瓷冠不同形态设计的应力特征，旨在为全瓷冠的临床修复设计提供依据。方法 三维有限元法。结果 全瓷冠受载时产生的张应力及剪切应力因其He而厚度不同而有差异，当He面厚度为1.0mm时，应力值最大：张应力23.35MPa，剪切应力30.76MPa。结论 临床制作全瓷冠时，冠的He面厚度宜在1.5mm以上，以提高全瓷冠的抗折能力。

Three-dimensional Finite Element Stress Analysis of Different Designs of Shape in All-ceramic Crowns

Objective The purpose of this study was to examine the effect of different occlusal thickness on the stress distribution of all ceramic crowns of the mandibular first molar. Methods Three dimensional finite element analysis was made.Results It was found that under the simulated applied loads, the values of tensile and shear stress varied with the occlusal thickness, and much greater values of such stresses were noticed in the all ceramic crowns 1.0 mm in occlusal thickness, compared with those in the crowns 1.5 mm and 2.0 mm in occlusal thickness. Conclusion These results could serve as a theoretic foundation for the clinical application of all ceramic crown, suggesting that the occlusal thickness of the crown should not be lower than 1.5 mm in order that the resistance of the all ceramic crown against fracture might be strengthened.