下颌第一磨牙半切术后两种双端固定桥修复的光弹性应力分析

Photoelastic Stress Analysis of Two Kinds of Rigid Fixed Bridge Design after Hemisection of Mandibular First Molar

目的观察下颌第一磨牙半切术后两种双端固定桥修复对牙槽骨应力分布的影响。方法以正常下颌第一磨牙受载为对照组,以下颌第一磨牙近中根半切术后,⑤⑥和⑤⑥⑦桥两种固定桥设计为实验组,运用光弹应力分析法,分析两种修复设计对第一磨牙半切术后余留区牙根周围支持组织应力分布状况的影响。结果两种双端固定桥修复后的牙槽骨应力值均大于对照组,但未超出其2倍;三基牙与双基牙两种双端固定桥设计的应力值间无显著性差异(P>0.05)。结论下颌第一磨牙半切术后选用双基牙双端固定桥的修复设计较适宜。

Objective To observe the effects of the two kinds of rigid fixed bridge design on the stress of the alveolar bone of mandibular first molar after hemiseetion. Methods The normal mandibular first molars were selected as control group. The two-abutment teeth and three-abutment teeth rigidly fixed bridge designs were selected as trial group. Stress distributions in the remaining sections of the alveolar bone models were evaluated with photoelastic stress analysis method. Results The stress values of two kinds of rigid fixed bridge design were higher than the control group but still below the twice. There was no significantly difference be tween two-abutment teeth rigidly fixed bridge design and three-abutment teeth rigidly fixed bridge design （ P 〉 0. 05 ）. Conelusion Two abutment teeth rigidly fixed bridge of mandibular first molar should be chosen after hemisection.