Effects of different culture media, cell densities and adhesion periods on stem cells from human exfoliated deciduous teeth after photobiomodulation

This study aimed to evaluate different culture media, cell densities and adhesion periods on stem cells from human exfoliated deciduous teeth (SHED) after photobiomodulation (PBM). SHED was cultured in either MEMα or DMEM with 10% Fetal Bovine Serum (FBS), let to adhere for 24 h or 48 h, submitted to 1%FBS, and irradiated. The following densities were tested: 2  ×  10³ (G1, G2), 1  ×  10⁴ (G3, G4), and 2  ×  10⁴ (G5, G6). PBM was applied at 20 mW for 10 s (5.0 J cm⁻²). Control groups were not irradiated (G2, G4, G6). MTT assay evaluated cell viability at 6 h, 12 h and 24 h. The comparison between different culture media revealed statistically significant differences among periods (p   <  0.05) and no difference among groups at all periods. The statistical analysis showed the interaction between cell density, period, and adhesion (p   <  0.001). The comparison between adhesion periods revealed that after PBM, at the first period G3 and G4 showed greater cell viability at 48 h of adhesion, while G5 and G6 had greater cell viability at 24 h of adhesion than at 48 h at both periods. G3, G5 and G6 had greater cell viability 24 h after PBM at 24 h of adhesion than at 48 h. Based on this study, the culture medium type MEMα or DMEM did not change the SHED viability after PBM. The adhesion period of 24 h, 6 and 24 h after PBM, the SHED density of 2  ×  10⁴ exhibited greater viability. However, with the adhesion period of 48 h, this SHED density showed a decreasing in viability, 6 and 24 h after PBM. Higher cell density (1  ×  10⁴ and 2  ×  10⁴) and shorter adhesion period (24 h) led to greater cell viability after PBM. (letter)