固定修复后倾斜基牙角度对牙周受力影响的有限元分析

Finite element analysis of the stress on dental surrounding tissues of different degree tilted tooth as a fixed bridge abutment

目的:分析第一磨牙缺失,采用双端固定桥修复,作为基牙的下颌第二磨牙倾斜不同角度时,基牙牙周膜等支持组织的应力分布情况,为临床修复提供理论依据。方法:采用三维激光扫描与Marc软件结合的方式,分别建立下颌第一磨牙缺失、下颌第二磨牙向近中倾斜时,行双端固定桥修复后的三维有限元模型,施加载荷计算并分析牙周膜支持组织中的应力分布状况。结果:当下颌第二磨牙近中倾斜24°时,其近中牙颈部牙周膜的应力值达到0°时的2倍,同时下颌第二前磨牙牙周膜受力也呈现上升趋势。结论:固定修复时,当牙齿倾斜达到或超过24°时,应慎重作为双端固定桥的基牙。

Objective： To analyze the stress distribution on the peridental membrane of different degree tilted abutment after the restoration of three-unit fixed partial denture. Methods： Five finite element models of three-unit fixed partial denture were constructed in which the second molar tilted at different degrees toward the second premolar by the combination of the three-demensional laser scanning technology and Marc software. A load of 230N was applied to the occlusal surface of the pontic from different direction. Stress distribution on the peridental membrane of the second molar and the second premolar were observed. Results： When second molar tilted at 24°, the stress peak value on the peridental membrane ofmesio-dental cervix was twice the normal second molar, and the stress value on the distal-dental cervix of the second premolar also increase accordingly. Conclusion： The tooth tilted more than 24° could not be selected as an abutment in the restoration of fixed partial denture.