Lombardo Luca, Bragazzi Romina, Perissinotto Carlo, Mirabella Davide, Siciliani Giuseppe
Postgraduate school of orthodontics, Ferrara University, Via Montebello 31, Ferrara 44100, Italy.
Prog Orthod. 2013 Sep 11;14:29. doi: 10.1186/2196-1042-14-29.
The aim of this study was to evaluate, in particular, whether bone resorption occurred at the extraction sites of a group of patients under orthodontic treatment, and, in general, whether extraction treatment predisposes patients to a greater degree of root resorption.
The study group comprised 12 class II division 1 malocclusion patients who underwent orthodontic treatment and extraction, and the control group comprised 10 class II division 1 patients who underwent orthodontic treatment without extraction. In both groups, treatments were carried out by the same operator using the same techniques. Cone-beam computed tomography performed before (T1) and after (T2) treatment was used to determine and compare the root length, the distance from the cementoenamel junction to the base of the defect and to the bone peak, the width of the defect and the buccolingual bone thickness.
Root length was reduced following treatment in both groups, although to a statistically significantly greater extent in the study group. The buccolingual bone thickness was reduced after treatment in both groups, with no differences found between the study and control groups. The bone loss at the sites assessed was greater in the patients after extraction treatment, with a statistically significant difference revealed between the two groups. The site that showed the greatest variation in both groups was distal to the upper canines.
In the present study, extractive orthodontic treatment appeared to predispose patients to a greater degree of root resorption. Indeed, the bone at the extraction site showed greater resorption in the study group with respect to the control group, and the appearance of intraosseous defects was noted in the former.
本研究的目的尤其在于评估一组接受正畸治疗的患者拔牙部位是否发生骨吸收，以及总体而言拔牙治疗是否使患者更易发生牙根吸收。
研究组由12例接受正畸拔牙治疗的安氏II类1分类错牙合患者组成，对照组由10例接受正畸非拔牙治疗的安氏II类1分类患者组成。两组治疗均由同一名操作者采用相同技术进行。利用治疗前（T1）和治疗后（T2）进行的锥形束计算机断层扫描来确定和比较牙根长度、从牙骨质釉质界到缺损底部和骨嵴的距离、缺损宽度以及颊舌侧骨厚度。
两组治疗后牙根长度均缩短，不过研究组缩短程度在统计学上显著更大。两组治疗后颊舌侧骨厚度均减小，研究组与对照组之间未发现差异。拔牙治疗患者评估部位的骨丧失更多，两组之间存在统计学显著差异。两组中变化最大的部位在上颌尖牙远中。
在本研究中，正畸拔牙治疗似乎使患者更易发生牙根吸收。事实上，研究组拔牙部位的骨吸收相对于对照组更明显，并且在研究组中发现了骨内缺损。
