A comparative study of the effect of the intrusion arch and straight wire mechanics on incisor root resorption: A randomized, controlled trial

Abstract

Objective: To analyze and compare external apical root resorption (EARR) of maxillary incisors treated by intrusion arch or continuous archwire mechanics. Materials and Methods: This cone-beam computed tomography (CBCT) study analyzed 28 deep bite patients in the permanent dentition who were randomly divided into two groups: Group 1, 12 patients with initial mean age of 15.1 6 1.6 years and mean overbite of 4.6 6 1.2 mm treated with the Connecticut intrusion arch (CIA) in the upper arch (Ortho Organizers, Carlsbad, Calif) for a mean period of 5.8 6 1.27 months. Group 2, 16 patients with initial mean age of 22.1 6 5.7 years and mean overbite of 4.1 6 1.1 mm treated with conventional leveling and alignment using continuous archwire mechanics for 6.1 6 0.81 months. The degree of EARR was detected in 112 maxillary incisors by using CBCT scans and a three-dimensional program (Dolphin 11.7, Dolphin Imaging & Management Solutions, Chatsworth, Calif). The CBCT scans were obtained before (T1) and 6 months after initiation of treatment (T2). Differences between and within groups were assessed by nonpaired and paired t-tests, respectively, with a 5% significance level. Results: Significant differences were found for both groups between T1 and T2 (P, .05) indicating that EARR occurred in both groups. However, there were no significant differences when EARR was compared between group 1 (0.76 mm) and group 2 (0.59 mm). Conclusions: The Connecticut intrusion arch did not lead to greater EARR of maxillary incisors when compared with conventional orthodontic mechanics.