Investigating the Effect of Photobiomodulation Therapy With Different Wavelengths of Diode Lasers on the Proliferation and Adhesion of Human Gingival Fibroblast Cells to a Collagen Membrane: An In Vitro Study.

Photobiomodulation (PBM) is considered a promising adjunctive approach in regenerative medicine. This study aimed to investigate the proliferation and adhesion of human gingival fibroblast (HGF) cells to a collagen membrane following PBM. Cultured HGF cells on a collagen membrane received PBM at wavelengths of 808 nm, 915 nm (2 and 4 J/cm), and 660 nm (2.1 and 4.2 J/cm) in interventional groups, while non-irradiated cells served as the control. On days 1 and 3 post-irradiation, cell proliferation was measured by MTT assay, and adhesion to the membrane was assessed under the scanning electron microscope (SEM). Cell proliferation significantly increased in interventional groups compared to the control, with the most significant increase at 915 nm (4 J/cm) in both time points. On the first day, the 808 nm and 660 nm lasers demonstrated similar results, significantly lower than the 915 nm laser (2 J/cm). On day 3, the 660 nm, 808 nm, and 915 nm (2 J/cm) groups showed comparable results. Qualitative analysis by the SEM identified spindle-shaped cells with multiple extended projections in 915 nm groups, especially at an energy density of 4 J/cm. Groups of 660 nm and 808 nm (4 J/cm) showed spindle-shaped cell morphology. No distinct cellular morphology indicative of enhanced adhesion was observed at 808 nm (2 J/cm). The most effective PBM setup for promoting HGF proliferation and adhesion to a collagen membrane was identified at 915 nm (4 J/cm).