Physicochemical and antibacterial properties of ZnO/chitosan-modified mineral trioxide aggregate composites

As one of the essential materials in dentistry, mineral trioxide aggregate (MTA) has been extensively used for root fracture repair, apexification, and root filling material due to its good sealing ability and biocompatibility. However, poor mechanical properties and low antibacterial efficacy are significant limitations of MTA for medical applications. To overcome these problems, we modified MTA by incorporating ZnO and chitosan in this study. The modification was performed by adding ZnO in various concentrations (5, 10, and 15 wt%) while preparing MTA and 4% chitosan solution as the hydration liquid. The modified-MTA samples were characterized with TG/DTA, XRD, FTIR, and SEM instrumentations. The effects of ZnO and chitosan on mechanical strength, radiopacity, pH, Ca2+ and Zn2+ ions release, and antibacterial properties of MTA samples were evaluated. It found that the modified MTA altered to a more compact structure and ultimately influenced the properties of hydrated products. The modified MTA's radiopacity and weight loss measurements complied with ISO standards as endodontic materials. Antibacterial evaluation against Enterococcus faecalis and Pseudomonas aeruginosa demonstrated enhanced efficacy due to the synergistic effect of ZnO and chitosan in MTA. Incorporating 10 wt% ZnO and 4% chitosan solution into the synthesized MTA was the optimum composition, significantly improving the mechanical and antibacterial properties. All the demonstrated tests revealed the potential of the modified MTA as a promising candidate for dental restorative material.