Antimicrobial and antifungal efficacy of Cassia fistula extracts incorporated in heat-cured acrylic resin: An in vitro study

Background: Denture-related stomatitis and other oral microbial infections are frequently observed among individuals wearing removable prostheses. The porous nature of polymethyl methacrylate (PMMA) denture bases promotes microbial adhesion and colonization. Incorporating plant-derived natural antimicrobials offers a promising strategy to enhance the bioactivity and antimicrobial potential of these materials.Aims and Objective: To evaluate and compare the antimicrobial and antifungal properties of Cassia fistula Linn. leaf extracts incorporated into PMMA acrylic resin against Staphylococcus aureus, Escherichia coli, and Candida albicans.Materials and Methods: Four experimental groups were prepared by incorporating Cassia fistula extract at 0.5%, 1.5%, 2.5%, and 3.5% concentrations into PMMA resin. Specimens (n=36 per group) were tested for antimicrobial activity using the agar diffusion method. Zones of inhibition were measured and statistically analyzed using ANOVA and post hoc Tukey’s test.Results: There was a significant dose-dependent increase in antimicrobial efficacy across all organisms. The 3.5% group produced the largest zones of inhibition for E. coli (17.10 ± 0.94 mm), S. aureus (14.92 ± 0.32 mm), and C. albicans (18.32 ± 0.40 mm) (p < 0.001).Conclusion: Cassia fistula extract demonstrated significant antimicrobial and antifungal properties when incorporated into PMMA, with enhanced effects at higher concentrations. This suggests its potential as a natural antimicrobial additive for prosthodontic materials.