Herbst双期拔牙矫治对颞下颌关节骨性结构影响的锥形束CT研究

Cone beam computed tomography analysis of the bony structure of the temporomandibular joint during two phase treatment with Herbst appliance

目的应用锥形束CT(CBCT)研究Herbst双期拔牙矫治对颞下颌关节骨性结构的影响。方法选取15例以下颌后缩为主要临床表现的恒牙列早期安氏Ⅱ类错患者,采用Herbst双期拔牙矫治,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)时进行CBCT扫描,应用Invivo Dental软件对CBCT图像进行三维重建和相关测量。结果 1)14例患者(28侧颞下颌关节)在T3期出现髁突后上区外侧边缘高密度、内部区域低密度类似"新月形"的增生影像。2)T3-T2期、T4-T1期,髁突前后径平均增加了0.62、0.66 mm(P<0.01);髁突头高度平均增加了0.54、0.53 mm(P<0.01)。结论 Herbst功能矫治器能促进髁突发生生长改建。

Objective This study assessed the effects of two-phase treatment with Herbst appliance on the bony structure of the temporomandibular joint via cone beam computed tomography （CBCT） analysis. Methods This study selected 15 patients exhibiting early permanent dentition and class Ⅱ malocclusion combined with mandibular retrusion treated by a two phase treatment （Herbst and fixed appliance）. The CBCT scans of the patients were obtained at the following stages： 2 weeks before Herbst treatment （T1）, at the start of treatment when the Herbst appliance was set in place （T2）, immediately after removal of the Herbst appliance （T3）, and immediately after removal of the edgewise appliance （T4）. Three-dimensional reconstruction and related measurements were performed using InvivoDental software, and the acquired data were statistically analyzed. Results 1） CBCT showed a crescent-shaped hyperplasia at the posterior-superior border of the condyles that the outer edge was highly dense and the inner region was lowly dense in T3 in 14 patients （28 condyles）. 2） In T3-T2 and T4-T1, the diameters of the anteroposterior condyles increased by 0.62 and 0.66 mm, respectively （P〈0.01）, and the condylar head height correspondingly increased by 0.54 and 0.53 mm （P〈0.01）. Conclusion Condylar growth remodeling occurs during Herbst treatment.