Synthesis and characterization of a dental cement based on bioactive glass/zinc oxide modified with organic resin as a novel pulp capping agent

Abstract

This study aimed to synthesize and characterize a novel dental pulp capping cement containing bioactive glass (BG)/zinc oxide modified with an organic resin. BG (45S5) with or without ZnO (Zn) and hemaphosphate (HP) combined with a liquid consisting of polyacrylic and itaconic acids (AA) were synthesized. Then, the structural, physical, and mechanical properties were assessed. Hydroxyapatite formation was evaluated by immersion in simulated body fluid. Biological analysis including methyl thiazolyl tetrazolium (MTT) assay, alizarin red staining, alkaline phosphatase (ALP) activity, and gene expression of odontogenic markers were performed to evaluate the cytotoxic effect and biomineralization potential of the cements on human dental pulp stem cells (hDPSCs). A commercial mineral trioxide aggregate (MTA) served as control. The highest compressive strength value and the shortest setting time were belonged to the BG+HP+AA and BG+AA groups, respectively. The shear bond strength to dentin was the highest for the BG+HP+AA cement. Scanning electron microscope showed only scarce deposits of calcium phosphate formation on the surface of the synthesized cements. BG+HP+AA and BG+HP+Zn+AA groups had significantly lower cytotoxicity than MTA. The mineralization potential of hDPSCs after stimulation by the novel cements increased. RT-qPCR showed higher odontogenic marker expression in hDPSCs exposed to the BG+HP+Zn+AA cement compared to other synthesized cements, although it was higher in MTA group. Based on the obtained results, the novel synthesized cements can be used as appropriate capping agents in the treatment of dental pulp.