Influence of Low-Level Laser on the Speed of Orthodontic Movement

Introduction: This study evaluated the effect of low-level laser irradiation on the speed of orthodontic tooth movement of canines submitted to initial retraction. Methods: Twenty-six canines were retracted by using NiTi spring (force of 150 g/side). Thirteen of those were irradiated with diode laser (780 nm, 20mW, 10 sec, 5 J/cm(2)) for 3 days, and the other 13 were not irradiated and thus were considered the control group. Patients were followed up for 4 months, and nine laser applications were performed (three each month). The movement of the canines was evaluated through 3D casts, and the statistical analysis was performed with ANOVA and Tukey tests (p < 0.05). Periapical radiographs of the studied teeth were submitted to Levander, Malmgreen, and alveolar bone ridge analyses to evaluate tissue integrity and were compared with the Wilcoxon test (p < 0.05). Results: A statistically significant increase in the movement speed of irradiated canines was observed in comparison with nonirradiated canines in all evaluation periods. No statistically significant difference was observed in bone and root resorption of canines, whether irradiated or not. Conclusion: The diode laser used within the protocol guidelines increased the speed of tooth movement. This might reduce orthodontic treatment time.