正畸治疗中上颌第二磨牙颊侧倾斜萌出相关因素的研究

Study on related-factors of buccal malposition of upper second molars in orthodontic treatment

目的探讨正畸治疗过程中影响上颌第二恒磨牙颊侧倾斜萌出的因素,为临床工作提供参考。方法选取84例正畸治疗患者,初诊时上颌第二磨牙均未萌出,正畸治疗结束时,上颌第二磨牙萌出建,且第二磨牙未经治疗。用Logistic回归分析正畸治疗后上颌第二磨牙颊倾的发生与第三磨牙的牙胚存在与否、是否拔牙、下颌平面角、错类型、治疗前牙弓后段拥挤度、治疗后牙弓后段拥挤度和第一磨牙前移量之间的关系。结果上颌第二磨牙颊侧倾斜与治疗后牙弓后段拥挤度密切相关(P<0.001),其它因素排除在外,逐步回归方程为Y=1.238X治疗后牙弓后段拥挤度-2.919。结论上颌第二磨牙的颊侧倾斜与治疗后牙弓后段拥挤度密切相关,牙弓后段越拥挤越容易发生颊倾。拔牙矫治可通过增加第一磨牙的前移来减少牙弓后段拥挤度,间接影响第二磨牙颊侧倾斜的发生。

Objective To investigate factors related to the buccal malposition of upper second molars in orthodontic treatment.Methods Eighty-four orthodontic patients were enrolled in this study. At first visit, the upper second molars of each subject have not erupted and erupted after the treatment but without any adjustment. Then Logistic regression was used to analyze the correlation between upper second molars buccal malposition and seven factors （including the existence of third molar germ, treatment with or without extracting teeth, ∠SN-MP, ∠ANB, crowding of posterior arch before treatment, crowding of posterior arch post-treatment and mesial movement of lower first molar）.Results Logistic regression revealed significant correlation between the buccal malposition of upper second molars and the crowding of posterior arch posttreatment （P0.001）, but other factors were excluded. The regression equation is Y=1.238X-2.919.Conclusion There is significant correlation in the crowding of posterior arch between the patients with and without buccal malposition of the upper second molar. Buccal malposition of the upper second molar tend to occur more frequently in patients with more crowding of posterior arch, and extracting teeth could reduce the crowding.