后牙全瓷冠的三维有限元分析

全瓷冠因其美观、生物相容性好,正逐渐应用于临床.本研究采用三维有限元法,分析下颌第一磨牙全瓷冠不同颈缘形态的应力分布规律,旨在为全瓷冠的临床应用提供依据.结果:全瓷冠承受垂直载荷时,龈向主要产生压应力,颊侧颈缘有张应力集中;全瓷冠表面应力＞冠内应力＞制备体应力;台肩型较凹面型全瓷冠的应力值小.由此提示,临床制作全瓷冠时宜设计台肩型,冠颈缘厚度应在0.5 ～1.0mm之间,冠表面应高度抛光,去除微裂纹,以提高全瓷冠的抗折能力.

Three-dimensional Finite Element Analysis of All-ceramic Crowns of the Posterior Teeth

The all-ceramic crown has been applied in clinical practice for its esthetic value and excellent biocompatibility. The purpose of this study was to examine the effect of different cervical marginal shapes on the stress distribution of all-ceramic crowns of the mandibular first molar by three-dimensional finite element analysis.The results showed that under vertical loading, the bearing compress stress on the occlusal region, the tensile stress concentration were observed at buccal cervical marginal of all-ceramic crowns; the stress at the surface of the crown was the highest, the stress inside the crown was higher than that inside the prepared teeth; the shoulder's stress value was lower than the cham fer's. These results lay the theoretic foundation for clinical application of all-ceramic crown, suggesting that the shoulder design should be recommended in clinical practice when the all-ceramic crowns are planned. The cervical thickness of the crown should be within 0. 5-1.0mm, and the crowns surface should be polished well to improve its resistance to fracture.