替牙晚期安氏Ⅲ类错畸形矫治后的髁突和下颌位置变化

Effects of orthodontic treatment on the condylar and mandibular positions of patients with class Ⅲ malocclusion in mixed dentition

目的探讨矫治替牙晚期安氏Ⅲ类错畸形后髁突和下颌位置的变化。方法选择患有替牙晚期安氏Ⅲ类错畸形的患者32例作为研究对象,均行前方牵引联合直丝弓矫治技术矫正,收集患者治疗前后的X线头颅侧位片进行头影测量分析。结果试验组患者矫治后的鞍角、Y轴角、下颌平面角、上齿槽座点-鼻根点-下齿槽座点角、颌凸角、髁顶点Co到y轴的距离等明显增大,面角、上下齿槽座角、髁顶点Co到x轴的距离、颏前点Pog到y轴的距离等明显减小,且差异具有统计学意义(P<0.05)。结论替牙晚期安氏Ⅲ类错患者通过正畸治疗后,下颌骨的生长可受到一定抑制,有效改善了上下颌骨的矢状不调状况,髁突点向后上移位,下颌的位置会发生明显的后移,并以髁突为中心发生了顺时针旋转。

Objective To evaluate the effects of orthodontic treatment on the condylar and mandibular positions of patients with class Ⅲ malocclusion in mixed dentition. Methods 32 patients with Angle class Ⅲ malocclu- sions in mixed dentition were chosen. They were treated with maxillary protraction and straight wire technique. Lateral cephalometric films were taken individually before and after treatment, and linear measurement were ob- served. Statistical analysis was performed using SPSS 16.0 software package. Results Cephalometric radiography： After treatment, SNA, ANS-Ptm, Co-y, At-y, Go-y, NSAr, NSGo, NSPog, ArGo＇-SN, Y axia, facial angle, ANB, Wits, NA-PA were increased significantly. Co-x, Pog-y, SNB, NP-FH, AB plane angle were decreased significantly （P〈0.05）. And Ar-y, Go-y, Pog-y change in value before and after correction of the order increases, NSAr, NSGo, NSPog changes in the value of the order also increased. Conclusion A significant backward upward shift of condylar point, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed, which contribute to the correction of a skeletal class Ⅲ relationship.