Low-level Laser Therapy in the Acceleration of Fixed Orthodontic Tooth Movement: Protocol for a Systematic Review and Network Meta-analysis

Abstract Background: Orthodontic treatment is a long-term therapy with time-related adverse effects. Low-level laser therapy (LLLT) has been used in the clinic as an intervention to accelerate orthodontic tooth movement (OTM) and prevent adverse effects. Previous systematic reviews have evaluated the effectiveness of LLLT in the acceleration of OTM. However, it remains unclear which treatment parameters are appropriate for LLLT. This review will evaluate the efficacy of LLLT on the acceleration of fixed OTM and the prevention of adverse effects.Methods: Several electronic databases will be searched. Grey literature also will be retrieved. Parallel or clustered randomised controlled trials that evaluated the effectiveness of different LLLTs on the acceleration of fixed OTM will be included. Two researchers will independently screen all titles, abstracts, and full-text articles retrieval, as well as data extraction. The risk bias of each study will be appraised using the Cochrane Risk of Bias tool (RoB 2.0). The primary outcome will be the efficacy of LLLT on the acceleration of fixed OTM (e.g., canine movement distance, orthodontic treatment duration). Secondary outcomes will be the effectiveness of LLLT to reduce orthodontic adverse effects such as pain and root resorption. The mean difference (MD) and relative risk (RR) with corresponding 95% confidence intervals (CI) will be chosen as effective measures for continuous and binary outcomes, respectively. When feasible, both fixed and random-effects pairwise meta-analyses and frequentist network meta-analyses will be conducted.Discussion: This network meta-analysis will compare the efficacy of LLLT on the acceleration of fixed OTM as well as whether LLLT can prevent adverse effects of this orthodontic treatment. By integrating the current evidence from direct and indirect comparisons and ranking all included interventions, our findings have the potential to help clinicians achieve more effective treatment goals.Systematic review registration: PROSPERO CRD42020175850