Physical Characteristics of TiO2 Photocatalyst in Cold Cure Denture Acrylic

Infections by Candida albicans may present problems to edentulous patients on soft tissue-borne prosthetics. Oral candidiasis may be inhibited through novel antifungal medicaments introduced into denture base resins. Studies show that Titanium dioxide (TiO2) a photocatalyst exhibits antimicrobial properties in various UV light-aided applications. The photocatalytic process creates oxidation products of hydroxyl radicals and superoxide anions upon light activation. Objectives: This study considers the inclusion of TiO2 photocatalyst in MMA denture acrylic. The purpose is to determine the mechanical limits of incorporating variable amounts of TiO2 into denture acrylic. Methods: Forty acrylic test beam specimens were fabricated with varying amounts of TiO2 at 3%, 5%, 10%, 20%, 30%, 40%, and 50% by net volume. Specimens were subjected to 3-point flexural test via the Instron and Knoop hardness test. The ANOVA test was used for multiple comparisons, to MMA control specimens of cold cure MMA denture acrylic. Results: For all specimens, no changes in cure rate or hardness were noted at any of the TiO2 loading levels. The color stability at increased TiO2 loading caused a change in color from medium pink to light pink. At 3% and 5% loading by volume, the change in tensile strength 46.1 ± 3.7 and 44.5 ± 4.8 MPa, respectively was noted and compared to control (48.4 ± 4.9 MPa) (p<0.05). At 20% loading, a 21% decrease in tensile strength was noted. Progressive decrease in tensile strength was established as we increased the TiO2 net volume. Conclusion: Structural stability is maintained at 3%, 5%, and 10% levels of TiO2. However, at concentrations of 20% and higher, there is a sustained reduction in flexural strength. Accordingly, denture resin impregnated with a low volume of TiO2 photocatalyst exhibits sufficient mechanical properties for potential clinical use.