Antifungal Efficacy and Surface Properties of Conventional and 3D-Printed Denture Base Materials Modified with Titanium Tetrafluoride (TiF4): In Vitro Study

<b>Background:</b><i>Candida albicans</i> adhesion to denture base materials is a primary contributor to denture stomatitis. To address this issue, numerous studies have explored the incorporation of various additives into denture base resins to enhance their antifungal properties. Titanium tetrafluoride (TiF₄) is an inorganic fluoride compound that has proven antimicrobial properties but has not yet been tested with denture materials. This study aimed to evaluate the effect of TiF₄ addition into different denture base materials on antifungal activity, surface roughness, hardness, and color properties. <b>Methodology:</b> A total of 200 disc-shaped specimens were prepared-100 heat-polymerized acrylic resins and 100 3D-printed NextDent resins. Four different concentrations of TiF₄ were incorporated: 1 wt%, 2 wt%, 3 wt%, and 4 wt% for both resins, while one group of each resin remained unmodified as a control. All specimens were subjected to thermal cycling for 5000 cycles, and four tests were conducted: <i>Candida albicans</i> adherence, surface roughness, hardness, and color change. A scanning electron microscope (SEM) was used to prove <i>Candida albicans</i> colonies' adhesion on the specimens' surfaces, and Fourier-transformed infrared (FTIR) analysis was performed to show the presence of TiF₄ in the resin material; data were analyzed using one-way ANOVA followed by a post hoc test (α = 0.05). <b>Results:</b> TiF₄ significantly reduced the <i>Candida albicans</i> adhesion to heat-polymerized specimens (<i>p</i> < 0.001). Compared to the control group, the incorporation of TiF₄ resulted in a substantial reduction in <i>C. albicans</i> colony counts, with reductions of approximately 97.6% in 1HP, 97.2% in 2HP, 97.4% in 3HP, and complete inhibition (100%) in 4HP. However, there was no significant difference between the 3D-printed ones (<i>p</i> = 0.913). Surface roughness, hardness, and color change of heat-polymerized groups were not significantly affected by TiF₄ (<i>p</i> > 0.05) except the color of the group treated with 4% (<i>p</i> < 0.05). For the 3D-printed groups, no significant differences were detected between the groups regarding candida count, hardness was significantly increased at 2% TiF₄ compared to the control (<i>p</i> = 0.002), and roughness was least with 4% TiF₄, while the color varied significantly between the groups (<i>p</i> < 0.001). <b>Conclusions:</b> TiF₄ addition decreased <i>Candida albicans</i> adhesion to heat-polymerized denture base materials but showed no antifungal effect on the 3D-printed resin. While roughness remained low in 3D-printed groups at higher concentrations. Hardness was not significantly altered in the heat-polymerized resin, whereas it increased significantly in the modified 3D-printed resin. Color stability was compromised at higher TiF₄ concentrations, particularly in the 3D-printed groups. The type of denture base material and TiF₄ concentration both influenced antifungal activity and denture surface properties.