DDS, UNI Dental Clinic, Seoul, Korea.
Am J Orthod Dentofacial Orthop. 2010 May;137(5):639-47. doi: 10.1016/j.ajodo.2008.05.016.
In this study, we used the finite element method to examine the optimum conditions for parallel translation of the anterior teeth under a retraction force.
Finite element models of the 6 maxillary anterior teeth and the supporting structures (periodontal ligament and alveolar bone) were generated as a standard model based on a dental model (Nissin Dental Products, Kyoto, Japan). After designating the position and length of the power arm as variables, the initial displacement of each tooth was measured with finite element simulation, and the rotation angle of each tooth was calculated.
The relationship between the position and length of the power arm was analyzed, and model equations for this relationship were proposed. As a result, the length of the power arm was either 4.987 or 8.218 mm when it was located either between the lateral incisor and the canine or between the canine and the first premolar, respectively.
The length of the power arm increased as its position was moved from the lateral incisor to the premolar. This was because the length of the power arm must be increased to be in equilibrium mechanically. Overall, it is expected that the efficient positions and lengths of the new dental models can be calculated if these total procedures are established as a methodology and applied to new dental models. Moreover, the parallel translation of the maxillary anterior teeth can be generated more effectively.
本研究采用有限元法，研究了在牵引下前牙平行移动的最佳条件。
基于牙科模型（日本尼辛齿科产品公司），生成上颌 6 颗前牙及支持结构（牙周膜和牙槽骨）的有限元模型。指定动力臂的位置和长度为变量后，通过有限元模拟测量各牙的初始位移，并计算各牙的旋转角度。
分析了动力臂的位置和长度之间的关系，并提出了该关系的模型方程。结果表明，当动力臂位于侧切牙和尖牙之间或尖牙和第一前磨牙之间时，其长度分别为 4.987 或 8.218mm。
动力臂的位置从侧切牙向尖牙移动时，其长度增加。这是因为动力臂的长度必须增加以达到力学平衡。总体而言，如果将这些总过程建立为一种方法并应用于新的牙科模型，则可以计算出新牙科模型的有效位置和长度。此外，上颌前牙的平行移动可以更有效地产生。
