Synthesis of Core–Shell Chitosan–TiO2 Nanoparticles and Its Impact on Candida albicans Biofilm Inhibition on 3D-Printed Denture Base Resins: An In Vitro Study

Objective: This study aimed to obtain a core–shell chitosan–TiO2 nanoparticle and to investigate its ability to inhibit Candida albicans biofilm formation when added to 3D-printed polymethyl methacrylate (PMMA) denture base resins. Materials and Methods: Ionic gelation was employed to prepare and characterize the nanoparticle, and Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray diffraction were used to identify the structure and morphology. Nanoparticle was added to 3D-printed denture resins at four different weight percentages (0.25%, 0.5%, 0.75%, and 1%) and antibiofilm activity was determined by carrying out Colony Forming Unite (CFU) counts after exposure to C. albicans. Results: The 0.25 wt.% chitosan–TiO2 group exhibited a significant reduction in colony-forming units (CFUs) compared to the control (p < 0.05). Although higher nanoparticle concentrations showed improved biofilm formation, this was most likely caused by nanoparticle aggregation, which interfered with surface homogeneity and biofilm resistance. Conclusions: Incorporating a 0.25 wt.% core–shell chitosan–TiO2 nanoparticle into 3D-printed denture base resin markedly improves its antibiofilm activity against Candida albicans while maintaining the material’s integrity.