目的建立不同冠根比的埋伏上颌中切牙及其周围组织的三维有限元模型,分析不同工况下的牙周膜应力分布,从而为临床上牵引埋伏牙提供参考。方法选取一名上颌中切牙水平阻生患者的CBCT数据,建立上颌中切牙的模型并截成1∶0.25、1∶0.5、1∶0.75、1∶1四个冠根比,分别施加30 g、60 g、90 g的力,分析不同工况下牙周膜的应力分布。结果对于同一模型,当牵引力增大时牙周膜应力分布规律不变,仅应力值增大。同一牵引力下,随着冠根比不断减小,牙周膜应力越来越小,高应力区越来越集中。结论对于不同冠根比的埋伏牙可采用不同牵引力,牙根越长牵引力越大。
Objective To contruct 3 D finite element models of an impacted maxillary central incisor of different crown-root ratios and their supporting issues,to analyse stress distribution of periodontal ligament when various tractions were exerted,and to provide some reference for clinical treatment. Methods A patient whose maxillary central incisor was impacted was chosen and his CBCT data was used to construct 3D finite element models of the incisor which was cutted into four crown-root ratios： 1∶ 0. 25、1 ∶ 0. 5、1 ∶ 0. 75、1 ∶ 1,then their periodontal tissues were established. Various tractions（30 g,60 g,90 g） were exerted respectively. Then their Von Misis stress distribution was analysed. Results For the same modle,as the traction increased the stress distribution pattern remained the same,while stress value increased. For the same traction value,as the crown-root ratio decreased,the stress value also reduced,while the high stress aera became more and more concentrated. Conclusion We can apply different traction for tooth with different crown-root ratios. The longer the root is,the heavier extraction can be applied.
Journal of Harbin Medical University
finite element analysis