Dose‐dependent effects of photobiomodulation on stem cells from human exfoliated deciduous teeth cultured on polylactic acid films: An in vitro study

Abstract This study investigated the effects of photobiomodulation (PBM) on stem cells from human exfoliated deciduous teeth (SHEDs) cultured on polylactic acid (PLA) films. Cells received a single 660‐nm PBM application at nominal radiant exposures of 1 or 4 J/cm 2 (L1 and L4); non‐irradiated cultures comprised the control group (C). Metabolic activity was assessed by Alamar blue assay at 24, 48, and 72 h, cell cycle distribution by flow cytometry at 72 h, and morphology and surface coverage by scanning electron microscopy at 72 h. L4 showed greater metabolic activity than C at 24, 48, and 72 h, whereas L1 differed from C at 48 and 72 h ( p < 0.05); L1 and L4 did not differ significantly. At 72 h, L4 showed a greater G2/M fraction than both C ( p < 0.001) and L1 ( p < 0.05). Irradiated cells exhibited greater apparent surface coverage while maintaining a fibroblast‐like morphology. PBM therefore modulated metabolic activity, cell cycle distribution, and cell–material interactions in SHEDs cultured on PLA films, with the 4 J/cm 2 condition showing the most consistent pattern. These results indicate a dose‐related effect of PBM at the cell–biomaterial interface and suggest its potential role in tissue engineering approaches.