Department of Orthodontics, Gazi University, Ankara, Turkey.
Eur J Orthod. 2011 Dec;33(6):691-9. doi: 10.1093/ejo/cjq143. Epub 2011 Mar 4.
The aim of this study was to determine whether different evaluation methods may be the cause of the varied outcomes of research that have evaluated the effects of extraction and non-extraction therapy on jaw rotation. This retrospective study consisted of the pre- (T1) and post- (T2) treatment lateral cephalograms of 70 skeletal Class I subjects with an optimal vertical mandibular plane angle, who had undergone fixed orthodontic treatment. Thirty-five of the subjects (20 females and 15 males, mean age: 14.7 years) were treated with four first premolar extractions and 35 (22 females and 13 males, mean age: 15 years) without extractions. T1 and T2 radiographs were superimposed using Björk's structural method and Steiner's method of sella-nasion line registered at sella. A Wilcoxon test was used to evaluate the changes between T1 and T2 and the Mann-Whitney U-test to determine differences between the extraction and non-extraction and Björk and Steiner groups. No significant difference was found between the methods of Steiner and Björk according to the spatial changes of the cephalometric points in the extraction and non-extraction groups. The maxilla showed forward rotation in the extraction group and backward rotation in the non-extraction group with both superimposition methods, but the differences were not significant in either inter- or intraclass comparisons. The mandible showed forward rotation in the extraction group with both superimposition methods but, in the non-extraction group, forward rotation was recorded with Björk's method and backward rotation with Steiner's method. These findings were not significant in either inter- or intraclass evaluations. No significant difference was found between the groups or methods.
本研究旨在确定不同的评价方法是否是导致评估拔牙和非拔牙治疗对下颌旋转影响的研究结果差异的原因。这是一项回顾性研究，共纳入 70 名具有理想垂直下颌平面角的骨性 I 类患者，这些患者均接受过固定正畸治疗。其中 35 名患者（20 名女性，15 名男性，平均年龄：14.7 岁）接受了上颌四颗第一前磨牙拔除，35 名患者（22 名女性，13 名男性，平均年龄：15 岁）未接受拔牙治疗。使用 Björk 结构法和 Steiner 法将 T1 和 T2 侧位头颅片重叠，在蝶鞍注册 Sella-Nasion 线。使用 Wilcoxon 检验评估 T1 和 T2 之间的变化，使用 Mann-Whitney U 检验确定拔牙和非拔牙组以及 Björk 和 Steiner 组之间的差异。根据拔牙和非拔牙组中头影测量点的空间变化，Steiner 法和 Björk 法之间没有发现显著差异。两种叠加方法均显示上颌在拔牙组中向前旋转，在非拔牙组中向后旋转，但在组间和组内比较中差异均无统计学意义。在两种叠加方法中，下颌在拔牙组中均显示向前旋转，但在非拔牙组中，Björk 法记录为向前旋转，Steiner 法记录为向后旋转。在组间和组内评估中，这些差异均无统计学意义。组间或方法间无显著差异。
