基牙牙槽骨吸收对固定义齿应力分布的影响

Stress Distribution of Fixed Partial Denture Affected by Abutments with Absorbed Alveoli

目的观察基牙牙槽骨发生一定程度吸收时,固定义齿应力分布的变化。方法建立右侧下颌第一磨牙缺失的牙列模型,设计正常基牙的对照模型及基牙牙槽骨Ⅱ度吸收的实验模型,在ANSYS 5.5软件中进行有限元分析,观察最大应力值及其分布。结果与对照组相比,单个基牙牙槽骨Ⅱ度吸收时,固定义齿最大应力值及其分布无明显变化;当两侧基牙牙槽骨均有Ⅱ度吸收时,则基牙受力显著增加。结论从应力分布角度看,固定义齿修复中,当两侧基牙牙槽骨均有Ⅱ吸收时,增加基牙数目是有利的。

Objective To observe how the stress distributes when the alveolar absorption appears upon the abutments of fixed partial denture （FPD）. Methods The dentition models with the right mandibular first molar lost were established, and four models were then designed, including one contrast model and three experimental models which were based on the abutments with the alveolar absorption in Ⅱ degree. Finite element analysis was done with the help of software ANSYS 5.5. The maximum value of stress and its distribution were observed. Results Compared with the contrast model, when the alveolar absorption occurred only on unilateral abutment, it had little inference on the whole FPD. However, when it occurred on bilateral abutments, the stress increased significantly on the weakened abutments. Conclusion If the alveolar absorption appears on bilateral abutments, it is advised to add the amount of abutments in the designing of FPD for the sake of stress distribution.