Purpose: Although several prescriptions and techniques exist for comprehensive fixed appliance treatment, their treatment effects have not yet been adequately assessed in an evidence-based manner. The aim of this systematic review was to assess the therapeutic and adverse effects of various prescriptions or techniques for orthodontic appliances from randomized clinical trials on human patients.
Methods: Eight databases were searched up to July 2016 for randomized trials assessing any orthodontic prescriptions or techniques in human patients. After elimination of duplicate studies, data extraction, and risk of bias assessment according to the Cochrane guidelines, random effects meta-analyses with mean differences (MD) and their 95% confidence intervals (CIs) were performed.
Results: Compared to Roth preadjusted appliances, both Begg and modified Begg appliances were associated with statistically significantly worse occlusal outcome assessed with Peer Assessment Review (PAR) scores (1 trial, MD 3.1 points, 95% CI 1.9-4.3 points and 1 trial, MD 2.4 points, 95% CI 1.2-3.6 points, respectively) with low quality of evidence, due to bias and imprecision. Compared to a partially programmed fixed orthodontic appliance, a fully programmed appliance was associated with a statistically significant, but clinically irrelevant increase in treatment duration (1 trial, MD 2.4 months, 95% CI 0.6-4.2 months), supported by high quality of evidence. However, caution is needed in the interpretation of these results as only a limited number of small trials with methodological issues were available.
Conclusions: Based on existing trials, there is limited evidence to support any robust clinical recommendation regarding the prescriptions or techniques for fixed orthodontic appliances. Registration: PROSPERO (CRD42016042727).
Keywords: Adverse effects; Meta-analysis; Orthodontics; Randomized controlled trials; Treatment duration.