Effects of sodium hypochlorite and ethylenediaminetetraacetic acid on proliferation, osteogenic/odontogenic differentiation, and mechanosensitive gene expression of human dental pulp stem cells.

Sodium Hypochlorite (NaOCl) and Ethylene Diamine Tetraacetic Acid (EDTA) can change the biochemical and biophysical properties of dentin. However, the response of human dental pulp stem cells (hDPSCs) to NaOCl and EDTA-treated dentin remains unknown. This study was conducted to investigate the effect of NaOCl and EDTA on cell proliferation, osteogenic/odontogenic differentiation, and the response to mechanosensitive gene expression in hDPSCs. Dentin slices were treated with 5.25% NaOCl, 17% EDTA, and saline (0.9% NaCl) separately. The cell viability and osteogenic/odontogenic differentiation of hDPSCs were analyzed using scanning electron microscopy, cell counting assay, alkaline phosphatase (ALP) staining, and quantitative polymerase chain reaction (qPCR). Besides, the hardness was measured by a Vickers microhardness tester. The expression of mechanosensitive genes was detected by the qPCR assay. All the irrigant-treated dentin allowed cell attachment. The EDTA-treated dentin significantly boosted the ALP and osteogenic/odontogenic differentiation, followed by NaCl and NaOCl groups. Remarkably, these trends were similar to the expression of mechanosensitive genes but were different from the trends of hardness values. The effect of irrigant-treated dentin on regulating hDPSCs differentiation might correlate with mechanosensitive signals. Whereas, the hardness changes between groups might not produce significant roles in regulating osteogenic/odontogenic differentiation of stem cells on dentin surfaces.