Muhammet YALÇIN¹, Halime KENAR², Burak DAYI^1,, Reyhan ŞİŞMAN¹, Erdal KARAÖZ³

The aim of this study was to evaluate the effect of different dental light curing units on cellular senescence and proliferation rate of human dental pulp mesenchymal stem cells (hDP-MSCs). hDP-MSCs were seeded at a density of 1x10⁴ cells/cm² into a 96 well plate. Cells were allowed to attach for 24 h and Halogen curing unit, Light-Emitting-Diode and Plasma arc units (PAC-MOD1, PAC-MOD2, PAC-MOD3) were applied on the cells from 1.2 cm distance (8 mm air + 4 mm growth medium). Media of the wells was refreshed after irradiation and cells cultured at 37 ^oC in a 5% CO₂ incubator for 48 h. Cell growth was determined using the WST-1 cell proliferation assay. The same samples were fixed and evaluated for cellular senescence, the irreversible growth arrest of cells, by staining for SA-β-galactosidase activity. As statistical analyses, Mann-Whitney U test was used for senescence data evaluation and One-way Anova and Tukey HSD tests were used for proliferation data evaluation. Cell proliferation rate was significantly higher under PAC-MOD3 conditions than under Halojen curing unit and PAC-MOD1( p< 0.05). According to the senescence test results, there was no statistically significant difference between the experimental groups and the control group ( p > 0.05), but senescence of hDP-MSCs exposed to PAC-MOD2 was greater than the others. When the dental light curing units are used for polymerization of adhesive systems in pulp capping, this procedure may have effects on senescence and proliferation of dental pulp stem cells.

light curing units, dental pulp mesenchymal stem cells, cellular senescence, cellular proliferation