Comparison of alignment efficiency of different sizes of superelastic nickel-titanium archwires in the initial phase of fixed orthodontic treatment: A single-center, double-blind randomized clinical trial

Abstract

Introduction: This 3-arm parallel, double-blind study aimed to evaluate the alignment efficiency of 3 different diameters of superelastic nickel-titanium (NiTi) archwires during the initial phase of orthodontic treatment. Methods: Ninety-three patients with nonextraction treatment in the mandibular arch (using 0.022-in Roth prescription brackets) were randomly allocated into 3 groups: 0.012-in NiTi (group 1), 0.014-in NiTi (group 2), and 0.016-in NiTi (group 3). The alignment change was measured using the modified Little's irregularity index before archwire placement and every 4 weeks. The alignment efficiency of the 3 groups was analyzed. Results: Ninety patients were analyzed (group 1: n = 29, group 2: n = 31, and group 3: n = 30; overall mean age, 16.6 years). The overall Wald test analysis revealed that wire type was not statistically significant (P = 0.91), whereas time exhibited significance as expected (P <0.001). Furthermore, the interaction between wire type and time was not significant (P = 0.93). The time-adjusted estimated difference between 0.014-in and 0.012-in was −0.49 (95% confidence interval, −2.83 to 1.85; P = 0.68). The time-adjusted estimated difference between 0.016-in and 0.012-in was −0.45 (95% confidence interval, −2.95 to 2.05; P = 0.72). No harm was observed. Conclusions: The clinical performance of 3 different sizes of NiTi archwires was similar. In addition, 0.014-in and 0.016-in NiTi archwires demonstrated better performances in aligning any irregularities because of a greater number of wire deformations in the 0.012-in group. Registration: IR.TBZMED.REC.1395.1039. Protocol: The protocol was not published before trial commencement. Funding: None.