Comparative photobiomodulatory effects of 660 nm, 810 nm, and 940 nm diode lasers on platelet-rich fibrin: an ex vivo study on structural remodeling and VEGF/PDGF-BB release for enhanced periodontal healing

Photobiomodulation (PBM) using diode lasers has emerged as a promising adjunct to enhance tissue regeneration. This ex vivo study evaluated the effects of three diode laser wavelengths (660 nm, 810 nm, 940 nm) on platelet-rich fibrin (PRF) structural remodeling and growth factors (vascular endothelial growth factor (VEGF), platelet-derived growth factor-BB (PDGF-BB)) release to optimize periodontal healing. Twenty PRF samples from healthy volunteers were divided into non-irradiated controls and subgroups irradiated at specific wavelengths. Structural changes were analyzed via scanning electron microscopy (SEM), while VEGF and PDGF-BB concentrations were quantified using enzyme-linked immunosorbent assay (ELISA). SEM revealed that 940 nm irradiation induced the most pronounced structural alterations, with 80% irregular fibrin fiber arrangement under low magnification, compared to smoother fibers in controls. Conversely, 660 nm irradiation significantly increased growth factor release, with PDGF-BB levels rising to 52.89 ± 6.70 pg/mL (p < 0.001 vs. controls: 40.17 ± 2.75) and VEGF to 52.30 ± 27.54 pg/mL (p = 0.021 vs. controls: 41.83 ± 16.52). Statistical analysis (one-way ANOVA, paired t-tests) confirmed wavelength-dependent effects, with 660 nm and 810 nm showing comparable efficacy (p = 0.999), while 940 nm underperformed in growth factor release. These findings suggest that 660 nm irradiation maximizes growth factor secretion for accelerated healing, whereas 940 nm enhances structural integrity via fibrin network remodeling. This wavelength-specific duality offers a strategic framework for clinicians to tailor PBM protocols-prioritizing either biochemical or structural outcomes-in periodontal regenerative therapies. Further in vivo studies are warranted to validate these translational potentials.