Photobiostimulation as a modality to accelerate orthodontic tooth movement

Photobiostimulation refers to the alterations, produced by relatively low levels of irradiation, in chemical, physical, and metabolic processes in target tissues with little or no temperature changes. A number of investigations have focused attention on the use of two photobiostimulation modalities, low-level laser therapy (LLLT) and light-emitting diodes (LED), to accelerate orthodontic tooth movement (OTM). Many of these studies have been performed on animal models and patients, often with mixed results. The increase in tooth movement in studies that showed positive effects of laser therapy was about 0.5 mm/month in humans. However, no statistically significant changes in tooth movement rates were observed in some other studies. Conflicting results from different studies are attributed to the variability in parameters and lack of rigorous research design and statistical analyses. We conclude, upon review of the available literature, that the apparent increase in tooth movement obtained from use of LLLT can be of significant benefit in the clinic provided that more rigorous research, in both animal models and humans, is conducted to improve the consistency and predictability of laser and LED therapy usage.