目的：建立上颌唇向倒置埋伏中切牙及其支持组织的三维模型，分析其在不同工况下的牙周应力分布，为治疗上颌埋伏中切牙提供参考。方法利用锥形束CT（CBCT）原始数据，结合Mimics 10.01和Ansys 14.0软件建立上颌唇向倒置埋伏中切牙及其牙周组织的有限元模型。在埋伏牙切端沿其长轴垂直方向，分别加载20、30、40、50、60、70 g集中力，并测定不同工况下牙周膜Von Mises应力分布。结果牙周膜应力随牵引力的增加而增大，30 g力时最大Von Mises应力值为24919.0 Pa，在牙周膜的最适应力范围内且接近其最大值。结论矫治初期，上颌唇向倒置埋伏中切牙的适宜牵引力较小，约为30 g。%Objective This study aims to do the following: construct a three-dimensional finite element model of an labial inverted impacted maxillary central incisor and its supporting tissues, analyze stress distribution in the periodontal tissue when various tractions are exerted, and provide references for treating impacted maxillary central incisor. Methods A three-dimensional finite element model of labial inverted impacted maxillary central incisor and its periodontal tissues was established using Mimics 10.01 and Ansys 14.0 software based on original cone beam computed tomography (CBCT) data. Various traction values (20, 30, 40, 50, 60, and 70 g) were exerted on the incisal margin in the direction perpendicular to the impacted tooth. Different Von Mises stress values were determined. Results Stress distribution on the periodontal ligament increased with traction size. When 30 g traction was exerted on the labial inverted impacted maxillary central incisor, the Von Mises stress was 24 919.0 Pa, which was within the range of the optimum force and close to its maximum value. Conclusion The optimum traction for early orthodontic treatment of labial inverted impacted maxillary central incisor is nearly 30 g.
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