下颌固定义齿不同松动度基牙应力分布的三维有限元分析

目的建立不同动度基牙的下颌固定义齿模型,探讨松动牙作为固定义齿基牙的合理性,以期为进一步的临床应用提供实验依据和指导。方法采用螺旋CT扫描,应用PHOTOSHOP CS2与ANSYS 11.0软件相结合建立下颌复合式固定桥模型。结果当3Ⅰ°松动时各基牙应力值显著增大且能观察到明显应力集中现象;当5或7松动时各基牙应力值也有不同程度的增加,但应力变化过程中并未观察到突然的应力增大现象。结论复合固定桥当两端基牙松动时,尤其是单根牙松动时,对基牙应力分布影响较大不宜单独作为基牙;而多根牙对应力分布的影响较小,可单独作为基牙;复合固定桥中间基牙有松动时,其松动度不论是Ⅰ度还是Ⅱ度都不会引起明显的应力集中,可选作基牙。

Three-dimensional finite element analysis of stress distribution of loose abutment of mandibular fixed denture

Objective To establish 3-D finite element mode of mandibular fixed denture with loose teeth as abutment and discuss iis rationality in order to provide further clinical basis and guidance. Methods By SCT scanning technology in combination with PHOTO- SHOP CS2 and ANSYS 11.0 software,establish composite mandibular fixed bridge model. Results While the looseness was 3 I° de- gree,the stress of abutment teeth obviously increased,and stress concentration was observed through stress clouds; While the looseness was 5- or 7,the stress also increased to different degrees but no sudden increase of stress was observed. Conclusions When the abut- ment teeth at the two ends of composite fixed bridge are loose, especially when single rooted teeth are loose, the range of stress is ex- traordinary big,and they alone are not suitable to be abutment. Multi-rooted teeth have small effect on stress distribution,so they alone can be abutment. When the abutment teeth in the middle of composite fixed bridge were loose,no matter the looseness was I or 11 de- gree, they can not cause visible stress centralization, so they can be abutment.