使用有限元分析对一种新型自锁正畸托槽进行生物力学评估：LUMACA系统。

文献信息

中文摘要

目的： 本研究旨在使用二维静态有限元分析（FEA），在相同加载和建模条件下，比较评估两种LUMACA托槽配置与一种传统托槽配置相关的初始生物力学响应。方法：使用COMSOL Multiphysics构建包含牙齿、皮质骨和松质骨以及牙周膜（PDL）的二维有限元模型。在腭-前庭负荷下模拟三种配置：（1）标准位置的LUMACA托槽，（2）龈向（根尖向）位置的LUMACA托槽，（3）标准位置的传统托槽。每种配置在0.25至2.00 N的五个力水平下进行分析，并以1.47 N作为参考负荷。分析Von Mises应力、纵向和横向应变分布以及冠部和根尖探针点的位移，以表征机械响应和牙齿移动模式。结果：在所有三种配置中，牙冠和根尖均沿相同方向移动，旋转中心位于根尖之外；因此，所有配置均产生控制性倾斜。沿施加负荷方向的位移分量的根尖与牙冠比值（纯整体平移时等于1，绕根尖旋转时等于0）在龈向粘接的LUMACA托槽为0.771，在标准位置的LUMACA托槽为0.469，在传统托槽为0.227。相应的旋转中心分别位于根尖之外37.0、9.7和3.2 mm处。在1.47 N负荷下，牙冠与根尖之间的差异位移分别为0.050、0.211和0.516微米；因此，传统托槽产生的差异位移约为龈向粘接LUMACA托槽的十倍。在整个所检查的力范围内响应呈线性，表明三种配置的排序与负荷大小无关。结论：托槽槽沟位置显著影响牙-牙周膜复合体的生物力学响应。根尖向粘接的LUMACA托槽使旋转中心更远离根尖，并产生比传统设计更均匀的牙周膜变形模式。计算得到的应力分布和位移应解释为托槽配置之间的比较指标，而非临床结果的直接预测因素。

英文摘要

Objectives: This study aimed to comparatively assess, using a two-dimensional static finite element analysis (FEA), the initial biomechanical response associated with two LUMACA bracket configurations and a conventional bracket configuration under identical loading and modelling conditions. Methods: A two-dimensional finite element model comprising the tooth, cortical and trabecular bone, and periodontal ligament (PDL) was constructed using COMSOL Multiphysics. Three configurations were simulated under a palato-vestibular load: (1) the LUMACA bracket in the standard position, (2) the LUMACA bracket in a gingival (apical) position, and (3) a conventional bracket in the standard position. Each configuration was analysed at five force levels ranging from 0.25 to 2.00 N, with 1.47 N used as the reference load. Von Mises stress, longitudinal and transverse strain distributions, and the displacements of coronal and apical probe points were analysed to characterise the mechanical response and tooth-movement pattern. Results: In all three configurations, the crown and apex moved in the same direction and the centre of rotation lay beyond the root apex; therefore, all configurations produced controlled tipping. The apex-to-crown ratio of the displacement components along the applied load, which equals 1 for pure bodily translation and 0 for rotation about the apex, was 0.771 for the gingivally bonded LUMACA bracket, 0.469 for the LUMACA bracket in the standard position, and 0.227 for the conventional bracket. The corresponding centres of rotation were located 37.0, 9.7, and 3.2 mm beyond the root apex, respectively. Under a load of 1.47 N, the differential displacement between the crown and apex was 0.050, 0.211, and 0.516 micrometres, respectively; thus, the conventional bracket produced approximately ten times the differential displacement observed with the gingivally bonded LUMACA bracket. The response was linear across the entire force range examined, indicating that the ranking of the three configurations was independent of load magnitude. Conclusions: Bracket slot position substantially influenced the biomechanical response of the tooth-PDL complex. The apically bonded LUMACA bracket displaced the centre of rotation farther beyond the root apex and produced a more uniform PDL deformation pattern than the conventional design. The calculated stress distributions and displacements should be interpreted as comparative metrics between bracket configurations and not as direct predictors of clinical outcomes.