安氏Ⅱ~1错拔牙与非拔牙矫治对牙弓宽度的影响

目的比较拔牙与非拔牙矫治对安氏Ⅱ1错治疗前后牙弓宽度的影响。方法选取30例安氏Ⅱ1错病人的矫治前后模型作为研究对象,其中15例病人采取拔除4个第一前磨牙的方法矫治(拔牙组);15例病人采取非拔牙方法矫治(非拔牙组)。分别在上、下颌尖牙和磨牙区唇颊面最突出的位置进行牙弓宽度测量。结果拔牙组矫治前后比较上、下颌尖牙间宽度均增加,差异有显著性(t=2.23、2.78,P<0.05),非拔牙组矫治前后上、下颌尖牙间宽度变化比较差异无显著性(P>0.05);两组矫治前后下颌尖牙宽度变化差值比较差异有显著性(t=2.96,P<0.05),上颌尖牙间宽度增大,组间宽度变化差值比较差异无显著性(P>0.05)。两组上、下颌第二磨牙间宽度均无变化。结论安氏Ⅱ1错拔牙矫治与非拔牙矫治相比,前者不会引起牙弓的缩窄。

CHANGES OF ARCH WIDTH FOLLOWING EXTRACTION AND NONEXTRACTION TREATMENTS FOR CLASS Ⅰ1 MALOCCLUSION

Objective To compare the changes of arch width in anterior and posterior arch between extraction and nonextraction treatments in ClassⅡ1 malocclusions.Methods Thirty pre-and post-treatment study models of patients with ClassⅡ1 malocclusion were randomly selected,of which,15 were treated by four first-premolar extraction and 15 were treated without extraction.Measurements were made in the canine and molar regions from the most labial aspect of the buccal surfaces of the canines and the molars.Results The mandibular intercanine mean width and maxillary intercanine mean width of the extraction group were increased in both pre-and post-treatment groups,the difference was statistically significant(t=2.23,2.78;P<0.05).However,in the non-extraction group,changes of the width were not significantly different between the pre-and post-treatment groups(P>0.05);The mandibular intercanine mean widths were significantly different between the extraction and nonextraction groups before and after treatment(t=2.96,P<0.05),the maxillary intercanine mean widths increased,while the differences were not statistically significant(P>0.05).In both groups,changes of inter second-molar width were not statistically significant before or after treatment.Conclusion Regarding ClassⅡ1 malocclusion treatment,the extraction treatment is better than non-extraction treatment,in which,the former does not result in narrower dental arches.