Herbst双期拔牙矫治对颞下颌关节位置影响的CBCT研究

摘要

目的:探讨Herbst双期拔牙矫治对颞下颌关节位置关系的影响.方法:纳入15例恒牙列早期安氏Ⅱ类错(牙合)下颌后缩患者,一期矫治采用Herbst矫治器,然后拔除每位患者的4个前磨牙;二期矫治采用edgewise固定矫治器.在Herbst矫治器矫治前两周(T1期)、Herbst矫治器初戴入矫治时(T2期)、Herbst矫治器拆除时(T3期)及二期固定矫治器拆除时(T4期)分别拍摄锥形束CT(cone beam computed tomography,CBCT).应用InvivoDental软件对CBCT图像进行三维重建,再对颞下颌关节间隙进行测量,并进行统计分析.结果:T1-T2-T3期,关节前间隙先减小后增大,关节上间隙、关节后间隙先增大后减小;T3-T4期,关节上、后间隙进一步减小,关节前间隙无明显变化;与T1期比,T4各关节间隙的变化均无明显差异.结论:髁突在关节窝中的位置在Herbst矫治开始时向前下移位,一期功能矫治结束时尤其双期矫治结束时几乎回到了治疗前的位置.%Objective:To assess the effects of Herbst two phase treatment on temporomandibular joint(TMJ) position analyzed by CBCT.Methods:15 patients of permanent dentition with class Ⅱ malocclusion combined with mandibular retrusion were treated by Herbst appliance as the 1st phase,then the 4 1st premolars of each patient were extracted,the fixed appliance of edgewise was applied as the 2nd phase of treatment.CBCT examination was carried out at the following stages:2 weeks before Herbst treatment(T1),at the start of the treatment when Herbst appliance was placed(T2),immediately after Herbst appliance was removed(T3) and immediately after the edgewise appliance was removed(T4).The InvivoDental software was used to calculate the joint space of TMJ from the three -dimensional CBCT images.The acquired data were then statistically analyzed.Results:During T1-T2-T3 stages,the anterior joint space was decreased and then increased,superior joint space and posterior joint space were increased and then decreased.During T3-T4 stages,the superior joint space and posterior joint space decreased further,but anterior joint space did not change.No significant difference was found in the anterior joint space,superior joint space and posterior joint space between T1 and T4 stage.Conclusion:At the start of treatment with Herbst appliance,the condyle is displaced in an anterior and inferior direction.At the end of functional treatment,especially the end of two phase treatment,the condyle is drawed back nearly to the original position.