[Are self-ligating brackets more efficient than conventional brackets ? A meta-analysis of randomized controlled and split-mouth trials].

The aim of this systematic review and meta-analysis was to compare self-ligating brackets (SLBs) considered as a whole to conventional brackets (CBs). An electronic search was performed in three databases (PubMed, MEDLINE via Web of Science, Cochrane Library) from their origin up to June 2017. Additional articles were hand searched from January 2006 to June 2017. This meta-analysis was restricted to randomized controlled trials (RCTs) and split mouth design studies (SMDs). No distinction was made between active and passive SLBs. The following variables were investigated : treatment duration, number of visits, alignment rate, rate of space closure, perception of discomfort during the initial phase of treatment, pain experience during wire insertion or removal, bond failure rate, time to ligate in or to untie an archwire, periodontal indices, occlusal outcomes, transverse arch dimensional changes and root resorption. 25 RCTs and 9 SMDs were finally selected. It was more painful to insert or remove a 0.019× 0.025 SS archwire in/from SLBs. It was significantly quicker to insert or remove an archwire from SLBs. There was less bleeding on probing with SLBs 4 or 5 weeks after bonding. All other variables did not exhibit any significant difference between SLBs and CBs. Out of the 31 comparisons between self-ligating and conventional brackets, 9 only revealed statistically significant differences. This meta-analysis contradicts most of the promotional statements put forward by the distributors.