Efficacy of elastic memory chains versus nickel-titanium coil springs in canine retraction: A two-center split-mouth randomized clinical trial

Objective: The use of newly-introduced elastic memory chains (EMCs) in space closure is increasingly gaining popularity. However, no clinical studies have evaluated their efficacy. Therefore, this study was conducted. Methods: In this two-center split-mouth single-blind randomized controlled trial, 21 jaws were divided into 42 quadrants. The two treatments [canine retraction using EMCs versus nickel-titanium (NiTi) coil springs (as control)] were randomly assigned to two quadrants of each jaw. The premolar space was measured at the baseline, and in the 1st, 2nd, and 3rd months of canine retraction, by a blinded orthodontist. Space closure rates were compared using a paired t-test. Results: The rates of space closure using NiTi springs were 1.93 +/- 0.62, 1.71 +/- 0.75, and 1.36 +/- 0.51 mm/month, during the 1st, 2nd, and 3rd months of treatment, respectively. The 3-month average rates of space closure were 1.67 +/- 0.39 and 1.89 +/- 0.36 mm/month in the NiTi and elastic groups, respectively (faster in the elastic group, P = 0.022). Conclusions: The application of elastic memory chains is as effective as NiTi springs. (C) 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.