Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil.
Eur J Orthod. 2012 Apr;34(2):170-5. doi: 10.1093/ejo/cjq178. Epub 2011 Mar 9.
This study evaluated the influence of intrusion mechanics combined with anterior retraction on root resorption of the maxillary incisors. A sample of 56 patients was divided into two groups: group 1 comprised 28 patients (12 females and 16 males), presenting with an increased overjet and deep overbite (6.48 and 4.78 mm, respectively) treated with reverse curve of Spee intrusion mechanics and group 2 comprised 28 patients (12 females and 16 males) with an increased overjet of 5.67 mm and a normal overbite of 1.12 mm. The initial mean ages for groups 1 and 2 were 13.41 and 13.27 years, respectively. Pre- (T1) and post- (T2) treatment periapical radiographs were used to evaluate root resorption. The groups were compared using the Mann-Whitney U-test. Correlation between root resorption and tooth movement was investigated with Spearman's correlation coefficient. The subjects in group 1 had statistically greater root resorption (P < 0.05) than those in group 2. The initial overbite severity and the amount of correction had significant positive correlations with root resorption (r = 0.324 and r = 0.320, respectively). The combination of anterior retraction with intrusive mechanics causes more root resorption than anterior retraction of the maxillary incisors alone.
本研究评估了前牙内收与压入联合作用对上颌切牙牙根吸收的影响。将 56 名患者分为两组：第 1 组包括 28 名患者（12 名女性和 16 名男性），表现为上颌前突和深覆颌（分别为 6.48mm 和 4.78mm），采用 Spee 反曲压入力学治疗；第 2 组包括 28 名患者（12 名女性和 16 名男性），上颌前突 5.67mm，正常覆颌 1.12mm。第 1 组和第 2 组的初始平均年龄分别为 13.41 岁和 13.27 岁。使用治疗前（T1）和治疗后（T2）的根尖周射线照片评估牙根吸收。使用 Mann-Whitney U 检验对两组进行比较。使用 Spearman 相关系数研究牙根吸收与牙齿移动之间的相关性。第 1 组的受试者有统计学上更大的牙根吸收（P<0.05）比第 2 组。初始覆颌严重程度和矫正量与牙根吸收呈显著正相关（r=0.324 和 r=0.320）。与单纯前牙内收相比，前牙内收与压入联合作用导致更多的牙根吸收。
