Influence of low-level laser therapy on the rate of orthodontic movement: a literature review.

Objective: The purpose of this study was to review low-level laser therapy (LLLT) protocols that have been used to date, and to indicate which parameters appear to be most effective to guide future research.

Background Data: Studies assessing the influence of LLLT on the rate of orthodontic tooth movement have produced controversial results as a result of methodological differences.

Methods: The MEDLINE(®) database (1975-2012) and the Cochrane library (subject 8) were reviewed. Clinical studies and animal experiments written in English and focusing on the effects of LLLT on the rate of orthodontic movement were browsed. Article selection was conducted by one reviewer and checked by a second investigator.

Results: A total of 109 articles were identified, of which 14 were selected for detailed analysis. Diode laser was used in all studies with different energies, frequencies, and doses. In animal studies, the most common and effective energy input was 54 J per session daily; in humans, it was 2 J per session on the first days of each month, with 72-96 h intervals. Orthodontic force also influenced orthodontic movement. A force of 10 g/force seems to be indicated for moving molars in rats, versus 150 g for canines in humans.

Conclusions: Most authors report positive effects of the use of LLLT on speed increase of orthodontic tooth movement when compared with control or placebo groups. Diode laser, especially gallium aluminum arsenide, used continuously and in direct contact with the irradiated areas, was the most frequent protocol. Further studies are warranted to determine the best protocols with regard to energy, dose, and intervention schedule.