Efficacy of a simplified photobiomodulation protocol in orthodontic patients: a randomized crossover clinical trial

ABSTRACT Introduction: Pain in orthodontic treatments results from an inflammatory process due to the application of forces. Despite photobiomodulation having shown effectiveness in reducing pain sensitivity, the method requires multiple sessions, which complicates its practical application in orthodontic clinics. Objective: To test a simplified protocol of photobiomodulation with a single application in adults undergoing orthodontic treatment. Material and methods: This single-blind, randomized, crossover study evaluated 30 participants undergoing fixed orthodontic treatment. Half of them received a single application of photobiomodulation, while the other half received a placebo, with group crossover after one month. The application was performed at 10 points using a GaAlAs diode laser (100 mW/cm2) immediately after appliance activation. Pain was assessed using a visual analog scale (VAS) at T0 (before the orthodontic check-up appointment), T24h (24 hours after the orthodontic control appointment), and T48h (48 hours after the orthodontic control appointment), and data were analyzed using two-way repeated measures ANOVA (time and intervention). Results: A total of 27 participants were evaluated. Pain was significantly higher at T24h than at T48h in both groups. Although there was no difference in pain sensitivity between the groups at T24h, pain significantly decreased in the intervention group after 48 hours. The variables of sex and age did not influence pain perception. Conclusion: The study shows that photobiomodulation can help control orthodontic pain, being well accepted by participants and not extending clinical time. However, the analgesic effects are still limited, indicating the need to refine the protocol to enhance its effectiveness.