舌侧活动翼矫治器联合微种植钉内收上前牙的生物力学研究

Biomechanical study of maxillary anterior teeth retraction using lingual active-wing appliance combined with micro-implants

目的探讨舌侧活动翼矫治器内收上前牙过程中,双弓丝体系联合腭中缝微种植钉支抗时,上颌牙齿的生物力学效应。方法选取1例双颌前突患者的锥形束CT数据,分别建立单、双弓丝体系;有、无种植钉内收上前牙的4个三维有限元模型。在模型上加力内收上前牙,分析对比上牙列的初始位移趋势和牙周膜应力分布。结果单、双弓丝体系对比组中,第一磨牙牙冠的矢状向位移量分别为-3.62E-4 mm、-2.64E-4 mm,上中切牙冠根位移差值分别为8.64E-3 mm、6.23E-3 mm。联合微种植钉,第一磨牙牙冠水平向、矢状向、垂直向位移量为6.96E-10 mm、5.46E-10 mm、2.28E-10 mm,上中切牙冠根位移差为1.20E-2 mm。结论双弓丝体系,更有利于后牙支抗的保护和前牙转矩的控制。联合微种植钉后,后牙支抗控制更好,"拱形效应"减弱,前牙转矩控制相对减弱。

Objective To evaluate the biomechanical effects of double-wire system combined with palatine micro-implant screws during the process of anterior teeth retraction using a lingual active-wing appliance.Methods Maxillary cone-beam CT data of patients who met the inclusion criteria were selected.Four three-dimensional finite element models were established to simulate anterior retraction using a lingual active-wing appliance with single or double wires,with or without palatine micro-implants.Forces were applied to each model to retract the maxillary anterior teeth.The initial displacement of the upper teeth and distribution of periodontal ligament stress were compared and analyzed.Results In the comparison between single and double wire systems,the sagittal displacements of the first molar crown were-3.62E-04 mm and-2.64E-04 mm,respectively.The displacement differences between crown and root of the maxillary central incisor were 8.64E-03 mm and 6.23E-03 mm,respectively.When combined with micro-implants,the first molar crown exhibited lateral,sagittal and vertical movements of 6.96E-10 mm、5.46E-10 mm and 2.28E-10 mm,respectively.Additionally,there was a displacement difference of 1.20E-02mm between the crown and root of the maxillary central incisors.Conclusions The double-wire system is more beneficial for protecting posterior teeth anchorage and controlling anterior teeth torque.However,when retracting the anterior teeth with palatal implants,optimal anchorage control of the posterior teeth can be achieved,and undesirable"bowing effect"side effects can be mitigated.There may be a weakening in controlling anterior tooth torque.