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_<i>S</i> series) was synthesized through a chemical reaction between tricalcium silicate (C₃S) powder and chitosan solution pretreated with acetic acid. Following this, the AC_<i>S</i> powders were subsequently physically blended with additional C₃S to enhance the mechanical properties, thereby developing a chitosan-based bioceramic composite, named the AC_<i>S</i>-C series. The antibacterial properties of the AC_<i>S</i>-C materials were systematically evaluated using minimum inhibitory concentration (MIC) assays, inhibition zone tests, and antibacterial assessments against <i>Escherichia coli</i> and <i>Streptococcus mutans</i> as well as biofilm testing with <i>Porphyromonas gingivalis</i>. 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_<i>S</i>-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_<i>S</i>-C samples exhibited key functional groups, including amino, amide, Si-O, CaO, and PO₄^3-. In this study, the AC_<i>S</i>-C series represent promising antimicrobial bioceramic pulp-capping materials that combine effective antibacterial activity with favorable biocompatibility.