Effects of pre-reacted glass-ionomer cement on the viability and odontogenic differentiation of human dental pulp cells derived from deciduous teeth

Surface reaction-type pre-reacted glass-ionomer (PRG) fillers have the ability to slowly release various ions. This study investigated the effects of cement-containing surface reaction-type PRG filler (PRG cement) on the viability and differentiation of human dental pulp cells derived from deciduous teeth (hDPC-Ds). Other materials generally used for pulp capping, Dycal and Fuji glass-ionomer cement Type II, were also tested by culturing hDPC-Ds with the extract of each material. The viability of hDPC-Ds was measured by methyl-thiazol-tetrazolium [3-(4, 5-di-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay. Odontogenic differentiation of hDPC-Ds was evaluated by alkaline phosphatase (ALP) activity and immunocytochemistry. The concentration of each ion in the extract was assessed by ion pair chromatography, inductively coupled plasma, and fluoride ion meter. Based on the results of ion analysis, a medium containing fluoride (F) and aluminum (Al) ions was reconstituted. Human DPC-Ds were cultured in this medium, followed by 3-(4, 5-di-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assays and measurement of ALP activity. PRG cement extracts were found to significantly enhance the viability, ALP activity, ALP staining in the extracellular matrix of hDPC-Ds, and release of F and Al ions. These ions, in turn, enhanced the viability and differentiation of hDPC-Ds. Taken together, these results indicate that the proliferation and differentiation of hDPC-Ds was enhanced by PRG cement and that F and Al, which elute from the PRG filler, were most likely involved in the proliferation and differentiation of hDPC-Ds. These findings suggest that PRG cement is potentially useful as a pulp capping agent.