Effect of 635-nm Photobiomodulation on Orthodontic Tooth Movement: a Randomized Split-mouth Clinical Trial

This study evaluated whether photobiomodulation (PBM), a form of low-level light therapy, can accelerate orthodontic tooth movement during canine distalization in adult patients undergoing fixed orthodontic treatment.

Eighteen adult patients requiring extraction of maxillary first premolars as part of orthodontic treatment for Class II malocclusion were enrolled. The study used a randomized, controlled, split-mouth design, in which one side of the maxilla was randomly assigned to receive PBM therapy, while the contralateral side served as an untreated control. This design allowed each participant to act as their own control.

All patients underwent standard orthodontic treatment with fixed appliances and absolute anchorage provided by orthodontic mini-implants. Canine distalization was performed using nickel-titanium closed-coil springs delivering comparable orthodontic forces on both sides. Photobiomodulation was applied on the experimental side using a 635-nm diode laser according to a predefined schedule over a 45-day period, while no laser treatment was applied on the control side.

The primary outcome was the amount of canine tooth movement, measured in millimeters at baseline and at follow-up visits using a calibrated orthodontic caliper. Tooth movement on the laser-treated side was compared with movement on the control side over time.

The purpose of this study was to determine whether photobiomodulation could safely and effectively increase the rate of orthodontic tooth movement without additional surgical intervention or pharmacological treatment.