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

<b>Objective</b>: This study aimed to obtain a core-shell chitosan-TiO₂ nanoparticle and to investigate its ability to inhibit <i>Candida albicans</i> biofilm formation when added to 3D-printed polymethyl methacrylate (PMMA) denture base resins. <b>Materials and Methods</b>: 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 <i>C. albicans</i>. <b>Results</b>: The 0.25 wt.% chitosan-TiO₂ group exhibited a significant reduction in colony-forming units (CFUs) compared to the control (<i>p</i> < 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. <b>Conclusions</b>: Incorporating a 0.25 wt.% core-shell chitosan-TiO₂ nanoparticle into 3D-printed denture base resin markedly improves its antibiofilm activity against <i>Candida albicans</i> while maintaining the material's integrity.