Objective: To compare the magnitude of external apical root resorption (EARR) of incisors in patients undergoing the initial phase of orthodontic treatment with two sets of brackets.
Materials and methods: According to the results of the power analysis for sample size calculation, 19 Angle Class I patients (anterior crowding: 3 to 5 mm; mean age: 20.6 years) were included in the study and randomly divided into two groups: group I (n = 11, self-ligating brackets) and group II (n = 8, conventional preadjusted brackets). The degree of EARR was detected in 152 upper and lower incisors by using cone-beam computed tomography (CBCT) scans and a three-dimensional program (Dolphin 11.5, Dolphin Imaging & Management Solutions, Chatsworth, Calif) with 25% level of sensitivity. The CBCT scans were obtained before (T1) and 6 months after initiation of treatment (T2). Differences between and within groups were analyzed by nonpaired and paired t-test, respectively, with 5% significance level.
Results: Significant differences were found for both groups between T1 and T2. However, no differences in the degree of EARR were detected between the groups studied.
Conclusions: Although EARR has occurred in all teeth evaluated, the bracket design (self-ligating or conventional) did not demonstrate any influence on the results observed.