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 single-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 significantly 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.