Photobiomodulation Promotes Odontoblast-Like Cell Activity via Reactive Oxygen Species and NF-κB: Implications for Dentin Regeneration.

Background: Low-level laser therapy has gained increasing attention in the field of dentistry as a promising modality due to its photobiomodulatory effects that facilitate tissue regeneration. Accumulating evidence suggests that neodymium-doped yttrium aluminum garnet (Nd:YAG) and erbium-doped yttrium aluminum garnet (Er:YAG) lasers, when applied at low-energy settings, can enhance cellular proliferation and promote mineralization in osteoblasts and mesenchymal stem cells. Objectives: This study aimed to investigate the photobiomodulation effects of low-level Nd:YAG and Er:YAG laser irradiation on rat odontoblast-like cells, with a particular focus on cellular proliferation, differentiation, and mineralization in vitro. Methods: Rat odontoblast-like cells (MDPC-23) were subjected to Nd:YAG and Er:YAG laser irradiation at a frequency of 10 Hz, with energy settings of 60, 80, 100, and 120 mJ for exposure durations of 0, 2, 5, 10, and 15 sec, respectively. The effects of low-level laser irradiation on cellular proliferation, differentiation, and mineralization were systematically evaluated. In addition, intracellular reactive oxygen species (ROS) levels were quantified, and an NF-κB inhibitor was employed to investigate its involvement in the regulation of cell proliferation and differentiation. Statistical analysis was conducted using one-way analysis of variance followed by post hoc Tukey's HSD tests. Results: Both Nd:YAG and Er:YAG laser irradiation at the energy of 80 mJ for 10 or 15 sec enhanced cell proliferation, differentiation, and mineralization in MDPC-23 cells. An elevation in cellular ROS levels was observed after laser irradiation, and the laser irradiation in the presence of the NF-κB inhibitor resulted in decreased cell proliferation and ALPase activity. Conclusions: Low-level Nd:YAG and Er:YAG laser irradiation enhanced the proliferation, differentiation, and mineralization of odontoblast-like cells in vitro. These effects appear to be mediated by the activation of the NF-κB signaling pathway through ROS, thereby promoting cellular proliferation followed by differentiation and mineralization.