上前牙角度与低角安氏Ⅱ类牙性错畸形拔牙矫治的相关性研究

Study on the relationship between the angle of upper anterior teeth and tooth extraction orthodontic treatment for lower angle Angle classⅡmalocclusion

目的研究上前牙角度与低角安氏Ⅱ类牙性错畸形拔牙矫治设计的相关性并得出临界诊断值。方法选择2009年1月至2019年12月在包头市中心医院口腔正畸科矫治结束的牙列拥挤在Ⅰ度以内、下颌平面角(MP-FH角)≤25°的低角安氏Ⅱ类牙性错畸形患者100例,其中拔除4颗第一前磨牙矫治患者50例(拔牙组),不拔牙矫治患者50例(不拔牙组)。对两组患者的矫治前头影测量数据进行统计分析,研究上前牙角度与拔牙矫治设计的相关性。结果反映上下颌骨位置关系的SNA角、SNB角、ANB角在拔牙组与不拔牙组的差异无统计学意义(均P>0.05),不能作为低角安氏Ⅱ类牙性错畸形拔牙设计的参考依据。反映上前牙角度的U1-NA距、U1-NA角、U1-L1角、U1-SN角以及MP-FH角在两组间的差异有统计学意义(均P<0.05)。接收者工作特征曲线(ROC曲线)分析可知,上前牙角度相关测量指标对低角安氏Ⅱ类牙性错畸形拔牙与否有诊断价值[曲线下的面积(AUC)>0.5]。根据约登指数求出最佳临界诊断值:U1-NA距为7.25 mm;U1-NA角为20.50°;U1-SN角为109.50°;U1-L1角为119.25°;MP-FH角为19.25°。结论上前牙角度与低角安氏Ⅱ类牙性错畸形病例进行拔牙矫治设计相关并具有诊断价值,相关测量项目的临界诊断值对于是否进行拔牙矫治设计有一定参考意义。

Objective To study the correlation between the angle of upper anterior teeth and the tooth extraction treatment design of lower angle Angle classⅡmalocclusion,and to obtain the critical diagnostic value.Methods Totally100 patients who finished orthodontics treatment were chosen from January 2009 to December 2019 in Department of Stomatology,Baotou City Central Hospital.All of them were diagnosed as the low angle Angle classⅡmalocclusion cases withinⅠdegree crowded and MP-FH≤25°.Fifty cases were treated by extraction of 4 first premolars(extraction group)and fifty cases without extraction(non-extraction group).The cephalometric data before treatment of the two groups were statistically analyzed to study the relationship between the angle of upper anterior teeth and the design of extraction.Results There was no significant difference in SNA angle,SNB angle or ANB angle between the two groups(P>0.05),which could not be used as the reference for extraction of low angle Angle classⅡmalocclusion.The variance of U1-NA distance,U1-NA angle,U1-L1 angle,U1-SN angle and MP-FH angle of mandibular plane angle between the two groups had significant difference(P<0.05).ROC curve analysis showed that the related measurements of the angle of upper anterior teeth had diagnostic value for the extraction of low angle Angle classⅡmalocclusion cases(AUC>0.5).According to the Youden index,their optimal critical diagnostic values were U1-NA distance being7.25 mm,U1-NA angle 20.50°,U1-SN angle 109.50°,U1-L1 angle 119.25°,and MP-FH angle 19.25°,respectively.Conclusion The upper anterior teeth angle is related to the extraction treatment design of low angle Angle classⅡmalocclusion cases,and it is diagnostic value.The critical diagnostic value of relevant measurement items has certain reference significance for whether or not performing extraction orthodontic design.