The Effectiveness of LLLT on Orthodontic Tooth Movement Acceleration: A Systematic Review of Human Studies

Background: Low level laser therapy (LLLT) has been verified efficacious in pain reduction. But the research results remain unclear and debatable in terms of orthodontic tooth movement (OTM) acceleration. Therefore, this systematic review was conducted to scrutinize the ability of photobiomodulation to increase the rate of orthodontic tooth movement.

Methods: A total of three databases were searched until July 2022. Controlled randomized clinical studies assessing the effect of photobiomodulation on the rate of orthodontic tooth movement published during the last 10 years in English were eligible to be selected. Study selection and data extraction were undertaken independently by two reviewers. Risk-of-bias (RoB) assessment was evaluated using Grade guidelines. The reporting of this review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results: A total of nine studies were identified for inclusion among 95 articles. A metanalysis could not be performed due to the heterogenity of the included studies. Six studies found a positive correlation between LLLT and acceleration of tooth movement. However, three trials found no significant difference between control and test group.

Conclusions: Based on the current moderate evidence, photobiomodulation could be an effective method on tooth movement acceleration. More well-designed randomized controlled trials are called for to obtain more clinically significant conclusions.