舌侧活动翼矫治器不同方式内收上前牙的三维有限元研究

3D FEM analysis of maxillary anterior teeth retraction by different methods with lingual active-wing appliance

目的:探讨舌侧活动翼矫治技术内收上前牙过程中,不同内收方式下,对上颌牙列的生物力学效应。方法:选取1例患者上颌骨和上牙列的CBCT数据,建立舌侧活动翼矫治器内收上前牙的三维有限元模型。设置3种内收方式:对上颌双侧中切牙分别施加0.49 N力(模型1);对上颌双侧中切牙及侧切牙分别施加0.49 N力(模型2);对上颌双侧中切牙、侧切牙及尖牙分别施加0.49 N力(模型3)。对比分析3种不同的内收方式下,上牙列的初始位移和牙周膜应力分布。结果:在模型1、2、3加力下,第一磨牙牙冠的近移量分别为-2.64E-04 mm、-7.24E-04 mm、-1.09E-03 mm。中切牙冠根位移差值分别为6.23E-03 mm、7.87E-03 mm、7.47E-03 mm。第二磨牙远中牙冠伸长位移分别为1.02E-04 mm、2.81E-04mm、4.22E-04 mm。结论:模型1的内收方式,最有利于后牙支抗的保护、转矩的控制和“拱形效应”的预防。

Objective:To evaluate the biomechanical characteristics of the lingual active-wing appliance on the maxillary dentition under different kinds of retraction methods by three-dimensional finite element method(3D FEM).Methods:The CBCT date of the maxillar and upper dentition of a patient was selected to establish a 3D FEM for retraction of anterior teeth with lingual active-wing appliance.3 types of conditions were set:The orthodontic force for each tooth with 0.49 N was applied on maxillary central incisors(model 1);0.49 N force for each tooth was applied on the maxillary central incisors and maxillary lateral incisors(model 2);0.49 N force for each tooth was applied on the maxillary central incisors,maxillary lateral incisors and canines(model 3).The initial displacement characteristics and the stress distributions of periodontal ligament of the maxillary dentition were compared among the 3 models.Results:On the m odel 1,2 and 3,the mesial displacement of the first molar crown were-2.64E-06 mm,-7.24E-06 mm and-1.09E-03 mm,the displacement difference between crown and root of the maxillary central incisor were 6.23E-03 mm,7.87E-03 mm and 7.47E-03 mm,the extrusion dis placement of the distal mesial crowns of the second molars were 1.02E-04 mm,2.81E-04 mm,and 4.22E-04 mm,respectively.Conclusion:Under the condition of model 1,the lingual active-wing orthodontic technique is the most conductive to the protection of posterior teeth anchorage,torque control and the prevention of“bowing effect”during the retraction of the anterior teeth.