Comparison of self-ligating brackets and conventional brackets in canine retraction during orthodontic treatment: systematic review and meta-analysis

The purpose of this study was to compare the canine retraction performance between orthodontic self-ligating and conventional brackets through a systematic review of the literature. Randomized clinical trials and controlled clinical trials, comparing canine retraction between self-ligating brackets and conventionally brackets, were identified through an electronic search in Medline, Embase, Web of Science, CENTRAL, China National Knowledge Infrastructure (CNKI), China Biology Medicine disc (CBM), and SIGLE, between January 1980 and December 2017. Primary outcomes included velocity of canine retraction and anteroposterior anchorage loss of first molars. Secondary outcomes included distal inclination of canines, mesial inclination of first molars, and canine rotation. Meta-analyses were conducted using Stata version 14.0. Seven studies were included, including six randomized controlled trials and one clinical controlled trial. The present meta-analysis revealed no significant differences regarding velocity of canine retraction (SMD=0.03; 95% CI: -0.59-0.64), anteroposterior anchorage loss of first molars (SMD=-0.47; 95% CI: -1.23-0.30), distal inclination of canines (SMD=0.001; 95% CI: -0.31-0.31), and mesial inclination of first molars (SMD=-0.07; 95% CI: -0.37-0.24) between self-ligating and conventional brackets. However, self-ligating brackets had less canine rotation than conventional brackets (SMD=-0.31; 95% CI: -0.60--0.01). Based on present evidence, self-ligating brackets control canine rotation better than conventional brackets in canine retraction.