In vitro comparison of induction capacity and biomineralization ability of mineral trioxide aggregate and a bioceramic root canal sealer

Abstract

To compare the effect of mineral trioxide aggregate (MTA) and iRoot SP, a bioceramic root canal sealer, on the cell viability, hard tissue deposition capacity and odontogenic differentiation of human tooth germ stem cells (hTGSCs). The dental materials MTA, iRoot SP and Dycal were packed into Teflon rings and placed on transwell inserts for toxicity evaluations by the MTS assay on days 3 and 7. Dycal was used as a positive control for the cell viability assay. Teflon rings were cocultured with hTGSCs, followed by the induction of odontogenic differentiation. The odontogenic differentiation of hTGSCs and biomineralization ability of the materials were evaluated by analysing the mRNA expression levels of dentine sialophosphoprotein (DSPP) and collagen type 1A (COL1A) by real-time polymerase chain reaction expression analysis, measurement of alkaline phosphatase (ALP) activity and visualization of calcium deposits by von Kossa staining. MTA and iRoot SP exhibited no cytotoxicity, but Dycal caused cytotoxicity (P < 0.05) of almost all of the cells after 7 days. MTA significantly stimulated (P < 0.05) the odontogenic differentiation of hTGSCs compared with iRoot SP. MTA and iRoot SP increased (P < 0.05) the mRNA levels of COL1A and DSPP mRNA compared with noninduced hTGSCs, which served as a negative control (NC). iRoot SP, however, significantly decreased (P < 0.05) COL1A and DSPP mRNA expression levels compared with the PC. MTA and iRoot SP induced hTGSC differentiation into odontoblast-like cells, but MTA might provide more inductive potential and hard tissue deposition compared with iRoot SP.