目的:通过测量28例患者正畸治疗前后角化龈宽度的变化以及牙齿位置的变化,分析正畸牙齿移动与角化龈宽度变化的关系。方法:对患者照片与模型进行匹配,通过测量牙冠长度而获得角化龈的宽度。在rapidform 2006上将治疗前后的上颌模型重叠,准确测量正畸移动前后牙齿(包括切牙、尖牙、前磨牙)的位置变化。统计牙齿压低伸长、内收与唇向移动、转矩变化与角化龈宽度的计量数据,分析其变化的关系。结果:对28例患者共213颗牙齿治疗前后数据的相关性进行分析发现,牙齿转矩角度的变化与角化龈宽度的变化有较强相关性(r=-0.47,P<0.001),并在多水平线性回归分析中验证了它们之间的相关性(回归系数<0,P<0.001),同时,牙齿内收和压低与角化龈宽度的变化没有显著相关性(P>0.05),尖牙和前磨牙回归系数为负(尖牙回归系数=-0.35,前磨牙回归系数=-0.38,P<0.05)。结论:正畸过程中的牙齿移动对角化龈的宽度会造成影响,唇向正转矩的增加更有可能引起角化龈宽度的减小;牙齿内收和压低与角化龈宽度的变化没有显著相关性;切牙相对于尖牙和前磨牙,在牙齿移动过程中更容易发生角化龈宽度的变化。正畸过程中,应该对牙齿位置变化可能对角化龈宽度造成的影响进行预判,关注角化龈宽度的变化。

Objective: The relationship between the orthodontic tooth movement and the change of keratinized gingival width was analyzed by measuring the keratinized gingival width and position of the teeth before and after 28 orthodontic treatments. Methods: The photos were matched to the model and the width of the keratinized gingival was obtained by measuring the length of the crown, and the keratinized gingiva. The pre- and post-treatment models were overlapped on rapidform 2006 and the change of tooth position before and after orthodontic movement could be accurately measured, and the relationship between tooth intrusion and extrusion, retraction and forward movement, torque variation and keratinized gingival width was statistically investigated. Results: Analysis of the correlation between data before and after treatments for 213 teeth in 28 patients revealed a strong correlation between changes in tooth torque angle and changes in keratinized gingiva width (r=-0.47, P<0.001). In the multi-level linear regression analysis, the correlation between them was verified (regression coefficient<0, P<0.001), and there was no significant correlation between the intrusion and retraction of the teeth and the change of the width of keratinized gingiva (P>0.05). Regression coefficient was negatively relative to the reference incisor between the teeth for the canines and premolars (canine regression coefficient=-0.35, premolar regression coefficient=-0.38, P<0.05). Therefore, the study found that there was a strong negative correlation between the changes in tooth torque angle and width of keratinized gingival (r=-0.41, P<0.001), that is, an increase in positive torque led to the reduction of width of keratinized gingiva, and on the contrary the increase of negative torque would cause the width of keratinized gingiva increase. There was no significant correlation between the intrusion and extrusion of the teeth for the width of keratinized gingiva. The sensitivity of different teeth for the width of keratinized gingiva differed, with incisor compared with canines and premolars that were more prone to keratinized gingiva width changes. Conclusion: Tooth movement during orthodontics affected the width of the keratinized gingiva width, and the increase in positive torque was more likely to cause a reduction in the width of keratinized gingiva. There was no significant correlation between the intrusion and retraction of the teeth and the change in the width of keratinized gingiva. Incisors were more prone to changes in the width of keratinized gingiva relative to the cuspids and premolars during tooth movement. In the orthodontic process, it is possible to predict the effect of changes in the position of the teeth on the keratinized gingiva width, and attention shoud be to the changes in the keratinized gingiva width.