Impact of different capping materials extracts on proliferation and osteogenic differentiation of cultured human dental pulp stem cells

This study aimed to evaluate the effects of four bioactive capping material extracts on the proliferation and osteogenic differentiation of human dental pulp stem cells. Four capping material extracts were evaluated in this study [Harvard MTA (calcium silicate), Retro MTA (calcium zirconia complex material), Activa Bioactive Base/Liner (bioactive glass-based material) and an experimental MCP-based pulp capping material). The materials prepared according to their manufacturers' instructions in the form of discs. Each material disc was placed into one insert of a 6-well plate and covered with Dulbecco's Modified Eagle Medium to produce extracts at 1:1 ratio. Human dental pulp stem cells represent the negative control group, cells cultured in osteogenic media represent the positive control group, while cells cultured on the tested extracts represent the test groups. Each specimen was assessed in triplicate by three independent assays. The proliferation of stem cells was evaluated via MTT assay and cell viability was determined by measuring optical density. Osteogenic differentiation was assessed via the alizarin red stain test by measuring the H-score and calcium concentration. The proliferation and osteogenic differentiation data were analyzed using one-way ANOVA followed by Tukey's post hoc multiple comparison test (p ≤ 0.05). Regarding MTT assay results, osteogenic media was significantly greater than calcium zirconia complex and MCP-based material. In comparison with negative control and calcium zirconia complexes, calcium silicate significantly increased the optic density. Alizarin red staining revealed significantly low H-scores and calcium concentrations in the four tested capping materials in comparison with control group. The calcium concentration of calcium silicate material was significantly greater than the remaining tested materials.Calcium silicate-based materials seem to have the most reliable performance concerning the proliferation and osteogenic differentiation of human dental pulp stem cells. Newly introduced resin-based materials have shown acceptable results but need further investigation. The present study had a few limitations; mainly the need to perform more laboratory evaluations and in vivo studies.