Abstract:

Objective　To assess the effects of maxillary protraction using facemask and the correlation between these effects and variables of quantitative cervical vertebral maturation（QCVM）. Methods　A total of 35 patients with skeletal Class Ⅲ malocclusion treated by maxillary protraction in the Orthodontic Department in Stomatology Hospital of China Medical University from Feb.2014 to Dec.2017 were selected in this study. Lateral cephalograms were taken before and after treatment. Skeletal and dental variables were measured，and the correlation between these effects and variables of QCVM was assessed by multiple-regression analysis. Results　There were no significant differences in A-X，ANS-X or B-Y（P > 0.05）. However，there were significant increases in the other measurements，such as SNA，ANB，FMA，U1-NA，Co-A，A-Y，U1-Y，PNS-X，B-X，Co-Gn，ANS-Me and Wits. SNB，IMPA and L1-Y were decreased（P < 0.05）. H4/W4 had a significantly negative influence on the change in A-Y and U1-Y（P < 0.05）. Conclusion　The facemask therapy shows a favorable effect on maxillary growth in patients with skeletal Class Ⅲ malocclusion. The more slender the fourth cervical vertebra is，the more difficult it is to treat.

Key words: skeletal Class Ⅲ malocclusion, facemask protractor, cervical vertebral maturation

摘要：

目的　评价使用面具式前方牵引器矫治生长发育期骨性Ⅲ类错牙合畸形患者的效果，并探讨颈椎骨龄定量分期法（quantitative cervical vertebral maturation，QCVM）中的变量与矫治效果的相关性。方法　选取2014年2月至2017年12月在中国医科大学附属口腔医院正畸一科进行面具式前方牵引矫治的生长发育期骨性Ⅲ类错牙合畸形患者35例，比较患者矫治前后的头影测量结果，并将矫治效果与QCVM中的变量进行多元线性回归分析。结果　相较于矫治前，矫治后测量结果中SNA角（由蝶鞍中心点、鼻根点及上齿槽座点所构成的角）、ANB角（由上齿槽座点、鼻根点及下齿槽座点所构成的角）、FMA角（眼耳平面与下颌平面的交角）和U1-NA角（上中切牙长轴与鼻根点-上齿槽座点连线交角），以及Co-A（髁顶点到上齿槽座点的距离）、A-Y（上齿槽座点到Y轴的距离）、U1-Y（上切牙切点到Y轴的距离）、PNS-X（后鼻棘点到X轴的距离）、B-X（下齿槽座点到X轴的距离）、Co-Gn（髁顶点到颏顶点的距离）、ANS-Me（通过前鼻棘点和颏下点做水平参考平面的平行线间距离）、Wits值增大，SNB角（由蝶鞍中心点、鼻根点及下齿槽座点所构成的角）、IMPA角（下中切牙长轴与下颌平面相交之上内角）和L1-Y（上切牙切点到Y轴的距离）减小，差异均有统计学意义（P < 0.05）。而矫治前后A-X（上齿槽座点到X轴的距离）、ANS-X（前鼻棘点到X轴的距离）和B-Y（下齿槽座点到Y轴的距离）的测量结果比较，差异无统计学意义（P > 0.05）。H4/W4（第四颈椎颈椎体上缘中点到最前下点和最后下点连线距离与第四颈椎颈椎体前缘中点到最后上点和最后下点连线距离的比值）与矫治前后A-Y、U1-Y的变化量呈负相关（P < 0.05）。结论　对于生长发育期骨性Ⅲ类错牙合畸形患者，面具式前方牵引矫治能有效促进上颌骨生长；患者第四颈椎越细长，矫治难度越大，前方牵引上颌骨的效果可能越不理想。

关键词: 骨性Ⅲ类错牙合畸形, 面具式前方牵引器, 颈椎骨龄