两种方式修复下颌中切牙不同长度残根的光弹应力分析

目的:探讨残根长度对桩核单冠及桩核联冠修复后应力分布的影响。方法:建立不同长度残根的三维光弹模型,对其进行常规桩核单冠及桩核联冠修复,运用光弹应力分析法分析修复后应力分布的影响。结果:正常长度残根应力峰值与天然牙无明显区别(P>0.05),缩短1/6残根应力峰值小于天然牙2倍,缩短2/6残根应力峰值单冠修复略大于天然牙的2倍,联冠修复小于对照组2倍,缩短3/6残根应力峰值单冠修复远大于天然牙的2倍,联冠修复略大于对照组2倍。结论:正常长度残根,缩短1/6残根可用桩核单冠或者联冠修复,缩短2/6残根应慎用桩核单冠修复,可用桩核联冠。缩短3/6残根不能用桩核单冠修复,应慎用桩核联冠修复。

The photoelastic stress analysis of mandibular teeth roots with different length restored with post-and-core crown.

Objective： To investigate the effects of the stress distribution of the roots with different length after the sin- gle-core crown and combined crown restoration. Method： To establish the Photoelastic Model of the roots with different length and restore it with single-core crown and combined crown. To analyse the stress distribution of the roots with different length after single-core crown and combined crown with Photoelastic stress analysis method. Result： There was no signifi- cantly difference between the stress crest values of the the root with normal length and the nature tooth （P 〉0.05）.The crest value of the root with shorting 1 / 6 length is lower than two times of the crest value of the nature tooth. The crest value of the root with shorting 2 / 6 length with post-and-core crown is two times higher than the nature tooth a little and the crest value of the root with shorting 2 / 6 length with combined crown is lower than two times of the crest value of the nature tooth. The crest value of the root with shorting 3 / 6 length with post-and,core crown is two times higher than the nature far and the crest value of the root with shorting 3 / 6 length with combined crown is two times higher than the nature a little. Conclusion： The residual roots with normal length and the length of shortening 1 / 6 should be repaired with post-and,core crown and combined crown,the residual roots with the length of shortening 2/6 should be repaired with post-and-core crown cautiously but it could repaired with combined crown, the residual roots with the length of shortening 3/6 should not be repaired with single-core crown but it could repaired with combined crown coutiously.