支抗力作用下上颌第一磨牙牙周膜应力的三维有限元分析

目的研究上颌第一磨牙在支抗力作用下牙周膜的应力分布情况。方法应用薄层CT技术以及ANSYS10.0有限元分析软件建立上颌第一磨牙及其牙周膜、牙槽骨的有限元模型。模拟3种不同大小的支抗力对模型中的上颌第一磨牙进行加载,应用三维有限元法分析上颌第一磨牙在支抗力作用下牙周膜的应力分布情况。结果当上颌第一磨牙颊侧中心受到近中水平向支抗力时,近颊根的颊侧近中颈部、近中颈部和腭侧根的近中颈部主要受压应力,远颊根的远中颊侧颈部主要受拉应力,牙周膜表面的最大应力值出现在近颊根的近中颈部。牙周膜有向近中腭侧转动的趋势。随着加载力的增加,牙周膜表面的应力值也随之增大。结论在临床正畸治疗时,应考虑第一磨牙颊侧是否能提供足够的支抗。

Analysis of stress in the periodontium of the maxillary first molar under the anchorage forces through three-dimensional finite element method

Objective The aim of this study was to analyse the stress distribution in the periodontium of the maxillary first molar used as the anchorage forces to provide biomechanical basis for the clinical practice. Methods By CT scanning and ANSYS10.0 finite element analysis software, a three-dimensional finite element model of the maxillary first molar and the periodontal tissue was established. Then, three different magnitudes of anchorage forces were applied to the molar to analyse the stress distribution in the periodontium of the maxillary first molar. Results Under anchorage forces, compressive stress distributed mostly at the mesio-buccal neck and mesio neck of the mesio-buccal root and the mesio neck of the palatal root, tensile stress distributed mostly at disto-buccal neck of the disto-buccal root. The maximum stress in the periodontium was situated at the mesio neck of the mesio-buccal root. The periodontium had the tendency of mesio-palatal rotation. With the anchorage force increased, the stress in the periodontium increased. Conclusion It should be consider if the buccal of maxillary first molar can provide enough anchorage during clinical practice.