双端固定桥两基牙牙周膜厚度分别不同时的生物力学分析

摘要

Objective: To study the effects of the different thickness of periodontal membranes around abutments to stress distribution of rigid fixed bridge. Methods: Two-dimensional images of mandible bones, teeth and periodontal supporting tissue of healthy people were scanned by spiral CT. Three-dimensional digital model was developed by imaging software. The three-dimensional finite element model of fixed denture on mandible posterior teeth was then developed. Stress distribution of fixed bridge loaded with the same vertical and horizontal forces was analyzed during different thickness of periodontal membranes around abutments. Results: There were no apparent differences in stress between the fixed bridge abutments and the surface of alveolar bones when the thickness of periodontal membrane around the abutments were less than 0.1 mm.When the thickness of periodontal membranes were between 0.1 mm and 0.4 mm, the stress of the alveolar bones surface reduced with the increase of the thickness of periodontal membranes, and there was a non-linear relationship between them. There was no change in the stress of the alveolar bones surface with the increase of the thickness of periodontal membranes when the thickness was more than 0.4 mm. Conclusions: Periodontal membranes around abutments exhibited cushioning effect when their thicknesses were in certain area. When it was too thicker or thinner, the cushioning effect will disappear.%目的:研究双端固定桥两基牙牙周膜厚度分别不同时对固定桥各部位应力分布的影响.方法:采用螺旋CT扫描获取健康人下颌骨、牙齿及牙周支持组织的二维图像,通过图像合成软件建立三维数字模型,并应用三维有限元分析软件生成下颌后牙固定桥的三维有限元分析模型.在相同垂直载荷和水平载荷情况下,分析两基牙牙周膜厚度分别不同时固定桥的应力分布.结果:当基牙牙周膜厚度小于0.1mm时固定桥基牙与牙槽骨表面应力大小相当;当基牙牙周膜厚度大于0.1mm小于0.4 mm时固定桥牙槽骨表面应力随牙周膜厚度增大而减小但非线性关系;基牙牙周膜厚度大于0.4 mm时固定桥牙槽骨表面应力不随牙周膜厚度增加而变化.结论:牙周膜的缓冲作用是在基牙牙周膜厚度的一定范围内,当牙周膜过窄或过宽时缓冲作用均减弱.