Abstract
BACKGROUND: This study assessed the effect of photobiomodulation (PBM) through single-dose diode 940 nm laser on pain after initial archwire placement. METHODS: This parallel-design clinical trial with 1:1 allocation ratio was conducted on 120 orthodontic patients with Class I molar relationship and 3-6 mm crowding, or overbite. Orthodontic brackets had been previously placed by an orthodontist. The patients were randomly assigned to three groups (n = 40) of PBM, placebo (laser in off mode), and control (no intervention). Right after initial archwire placement, patients in PBM group underwent 940 nm laser irradiation with 32 J/cm(2) energy density in contact mode, and five areas were irradiated. Laser in off mode was used for the placebo group. The level of pain experienced by patients after archwire placement was recorded subjectively by using a visual analog scale (VAS). The Pain Catastrophizing Scale (PCS) was filled out by patients after 7 days to assess the correlation of personal traits with actual pain. Data were analyzed by the Chi-square test, independent t-test, ANOVA, and ANCOVA (alpha = 0.05). RESULTS: Type of intervention had no significant effect on VAS pain score (P = 0.654) although slightly lower pain was recorded in the PBM group. Location of orthodontic wire placement (maxilla/mandible) had no significant effect on the pain score (P = 0.780), although the mean pain score in the mandible was slightly higher than that in the maxilla. CONCLUSION: In the present study, PBM delivered using a single-session 940 nm diode laser had no significant effect on pain after initial placement of orthodontic archwires. TRIAL REGISTRATION: Trial registration number: IRCT20230603058377N1. Retrospectively registered. Registration date: 08/07/2023.