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Abstract

Background/purpose

Light-emitting diode-based photobiomodulation (LED PBM) potentially reduces pain and root resorption risk in orthodontics. This study evaluated 850-nm LED PBM effects on pain and dentin sialoprotein (DSP) levels during canine distalization.

Materials and methods

This single-blind, parallel-group randomized controlled trial included 16 orthodontic patients (8 per group). Participants were randomly allocated in a 1:1 ratio to either an active LED group or a sham control group. Pain intensity was assessed using a visual analog scale (VAS) at 0, 24, and 48 hours following canine distalization at four consecutive monthly visits (T1-T4) and expressed as the area under the curve (AUC0-48h). DSP concentrations in gingival crevicular fluid were measured at pretreatment (T0), initiation of distalization (T1), and follow-up visits (T2, T3) using sandwich ELISA. Longitudinal changes were analyzed using linear mixed-effects models.

Results

The LED group demonstrated a significantly lower pain intensity compared with the control group, with a significant group-by-time interaction (χ² = 9.46, P = 0.024). Adjusted mean values of AUC0-48h were significantly reduced in the LED group at T3 and T4, with the greatest difference observed at T3 (P < 0.001). A significant group-by-time interaction was observed for DSP (χ² = 9.75, P = 0.021), with lower DSP levels in the LED group being reported at T1, T2, and T3 compared with the control group (P < 0.05).

Conclusion

Repeated 850-nm LED PBM was associated with reduced cumulative pain and attenuated DSP increases during canine distalization, suggesting potential benefits for patient comfort and root resorption–related responses.

Publication Date

2026

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