上中切牙全瓷冠切端瓷厚度与应力关系的三维有限元分析

目的　为全瓷冠的临床设计提供依据。方法　采用三维有限元法分析不同切端瓷厚度 (切龈向厚度 )的上中切牙全瓷冠受载的应力状况。结果　全瓷冠唇舌侧颈缘有张应力、压应力集中 ;全瓷冠表面应力 >冠内应力 >制备体应力 ;切端瓷厚度为 1.5mm及 2 .0mm全瓷冠的应力分布相似 ,应力值也非常接近。结论　建议在临床制作前牙全瓷冠时 ,预备切端瓷厚度在 1.5mm以保障全瓷冠的抗折能力 ,而磨除过多的切端牙体组织并不能提高全瓷冠的强度

Three-dimensional Finite Element Stress Analysis of Different Incisal Length of Ceramic in All-ceramic Crowns

Objective To examine the effect of different incisal length of ceramic on the stress distribution of all-ceramic crowns of upper central incisor. Methods Three-dimensional finite element analysis were used. Results The results showed that compressive stress and tensile stress and shear stress concentration were observed at some certain regions of the all-ceramic crowns under simulated applied loads. The values of stress at the surface of the crown was the highest, and that of the inside surface was higher than that inside the prepared teeth. There was little difference between the crowns with length of 1.5 mm and 2.0 mm in stress analysis. Conclusion The results suggested that it wouldn't help to increase the resistance to fracture by grinding off more incisal tissue when the incisal length of the ceramic crown had reached 1.5 mm.