Abstract

Tricalcium silicate (C 3 S) has been recognized as an important bioactive material and has attracted considerable attention in the field of endodontic therapy in recent years. However, pure C 3 S was found to exhibit insufficient X-ray opacity, while its setting time, antibacterial properties, and mechanical strength required improvement, thereby limiting its clinical applicability in pulp capping procedures. To improve the properties of C 3 S materials, a novel pulp capping material was developed in this study, composed of tricalcium silicate, calcium chloride, zirconium oxide, and Quaternized chitosan/ tannic acid hydrogel (QT hydrogel). The material was comprehensively characterized in terms of its setting time, compressive strength, handling properties, washout resistance, solubility, microstructure, pH variation, antibacterial performance, and cytotoxicity. Experimental results indicated that the 60% QT hydrogel/ C 3 S and calcium chloride (CaCl 2 ) powder mixture (QT/CSC) exhibited a shortened setting time, high compressive strength, excellent washout resistance, and significant antibacterial activity. Following the incorporation of 20% ZrO 2 , the 20% ZrO 2 /QT/CSC composite demonstrated outstanding radiopacity. Cytotoxicity assays confirmed the favorable biocompatibility of the material. These findings suggest that the 20% ZrO 2 /QT/CSC composite represents a highly promising candidate for clinical pulp capping applications.