Effects of High-Calcium/Phosphorus Bioactive Glass on Human Dental Pulp Stem Cells and Interfacial Reactivity Observed by 31P Nuclear Magnetic Resonance.

INTRODUCTION AND AIMS: This study aimed to evaluate the biocompatibility and regenerative potential of a novel bioactive glass with high calcium and phosphorus contents (HCaP-BG) in human dental pulp stem cells (hDPSCs), and to investigate the formation of apatite-like calcium phosphate on the bioactive glass surface using ³¹P solid-state magic-angle spinning nuclear magnetic resonance (NMR). METHODS: HCaP-BG was synthesized via the melt-quench method. Its effect on hDPSCs proliferation was assessed using a colourimetric cell viability assay (CCK-8), and cytotoxicity was evaluated using a lactate dehydrogenase assay. Cell morphology was observed using field-emission scanning electron microscope. Mineral deposition was examined using Alizarin Red S staining. Odontogenic differentiation was assessed by real-time quantitative PCR analysis of dentin matrix protein 1 expression. To evaluate interfacial reactivity, HCaP-BG was immersed in simulated body fluid for 21 days, followed by analysis via solid-state 31P NMR spectroscopy. RESULTS: HCaP-BG demonstrated no significant effect on the proliferation of hDPSCs and exhibited no cytotoxicity. hDPSCs directly exposed to HCaP-BG maintained normal morphology. Alizarin Red S staining showed visible calcium deposits in the experimental group. Expression of dentin matrix protein 1 was significantly upregulated at days 14 and 21 following HCaP-BG exposure. Solid-state 31P NMR analysis indicated the formation of amorphous calcium phosphate. CONCLUSIONS: HCaP-BG demonstrated good biocompatibility and promoted the formation of a biomimetic layer primarily composed of amorphous calcium phosphate, with minor hydroxyapatite component. CLINICAL RELEVANCE: HCaP-BG exhibited biocompatibility and modulation of hDPSC behaviour, indicating its potential for dentin repair.