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目的:比较平直不锈钢方丝、前牙段带20°正转矩的不锈钢方丝与复合转矩弓丝在内收上颌前牙时上颌4个切牙的位移趋势和牙周组织应力分布。方法:建立包含矫治器的上颌三维有限元模型,运用三维有限元分析,分别为复合转矩弓丝和带20°正转矩的不锈钢方丝上颌四颗切牙施加相对应的方向为牙冠唇向、牙根舌向的位移载荷,并对3种弓丝整体施加1.47N的内收力,计算得到牙周膜应力分布情况。结果:在前牙内收时,使用平直不锈钢方丝时,主要表现为冠舌向的转矩运动,使用另外2种弓丝时,主要表现为冠唇向的转矩运动,使用复合转矩弓丝的牙周膜应力分布与带转矩的不锈钢丝类似,但最大主应力分布面积明显小于不锈钢丝组,其最大主应力值与带转矩不锈钢丝相比也大为减小。结论:在前牙内收阶段使用复合转矩弓丝,能保持4个前牙的正常唇倾度,前牙接近整体移动,且最大主应力值明显较带20°正转矩的不锈钢方丝小,更符合生理移动的要求。
OBJECTIVE: To compare the displacement trend of maxillary incisors and the stress distribution in periodontal tissues during the insertion of maxillary anterior teeth with stainless steel square wire with a positive torque of 20 ° and square anterior teeth in the anterior teeth. Methods: The maxillary three-dimensional finite element model including appliance was established. The three-dimensional finite element analysis was performed on the composite torque arch wire and the four maxillary incisors of stainless steel square wire with a positive torque of 20 ° Lips, teeth of the tongue to the displacement load, and the three kinds of arch wire as a whole exertion of 1.47N internal force, calculate the periodontal ligament stress distribution. Results: When the anterior teeth were adducted, the use of flat stainless steel square wire, the main performance of the crown tongue to the torque movement, the use of the other two kinds of arch wire, the main performance of the crown lip to the torque movement, the use of composite turn The stress distribution of periodontal ligament of moment arch wire is similar to that of stainless steel wire with torque, but the distribution area of maximum principal stress is obviously smaller than that of stainless steel wire group. The maximum principal stress value is also greatly reduced compared with that of torque stainless steel wire. Conclusions: The use of composite torque arch wire in the adduction phase of the anterior teeth can maintain the normal lip inclination of 4 anterior teeth and the anterior teeth move closer to the whole, and the maximum principal stress value is significantly higher than that of stainless steel square wire with 20 ° positive torque Small, more in line with the requirements of physiological movement.