Chitosan-Based Antibacterial Bioceramic Materials for Dental Pulp Capping

Conventional clinical approaches for regenerative endodontic procedures, root canal therapy, and vital pulp therapy often lack sufficient antimicrobial efficacy, thereby increasing the risk of post-treatment apical periodontitis. To overcome this limitation, a series of antimicrobial powders (referred to as the AC_S series) was synthesized through a chemical reaction between tricalcium silicate (C₃S) powder and chitosan solution pretreated with acetic acid. Following this, the AC_S powders were subsequently physically blended with additional C₃S to enhance the mechanical properties, thereby developing a chitosan-based bioceramic composite, named the AC_S-C series. The antibacterial properties of the AC_S-C materials were systematically evaluated using minimum inhibitory concentration (MIC) assays, inhibition zone tests, and antibacterial assessments against Escherichia coli and Streptococcus mutans as well as biofilm testing with Porphyromonas gingivalis. In addition, biocompatibility was assessed through cytotoxicity tests using L929 fibroblast cells. The results revealed that the AC₂₀-C formulation exhibited good antibacterial efficacy (exceeding 90%), maintained over 80% cell viability, exhibited a clear inhibition zone, and effectively inhibited biofilm formation. Regarding physical properties, the AC_S-C materials were able to set within 30 min and possessed sufficient compressive strength. Further structural analysis using energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy verified the successful synthesis and structural integrity of the material. The AC_S-C samples exhibited key functional groups, including amino, amide, Si-O, CaO, and PO₄^3-. In this study, the AC_S-C series represent promising antimicrobial bioceramic pulp-capping materials that combine effective antibacterial activity with favorable biocompatibility.