Antimicrobial Photodynamic Therapy With Curcumin And Rose Bengal Against Oral Biofilms: Light-Dependent And Independent Effects

Abstract

Aim: Streptococcus mutans and Candida albicans serve as crucial microorganisms in oral illnesses, associated with tooth caries and opportunistic infections. Their biofilm-forming ability reduces susceptibility to conventional antimicrobials, complicating treatment.(1,2) This study aimed to evaluate the antimicrobial efficacy of curcumin (CUR) and Rose Bengal (RB) in photodynamic therapy (aPDT) against mono-species biofilms of Streptococcus mutans and Candida albicans, comparing light-dependent and light-independent effects.

Methods And Methods: Clinical isolates of S. mutans (n=100) and C. albicans (n=100) from patients (Jan–Sep 2024) were treated with optimized concentrations of curcumin (CUR, 100 μM) or Rose Bengal (RB, 50 μM), determined via pilot testing. Biofilms were exposed to blue light (450–470 nm, 1000 mW/cm², 1 min) or kept dark. Metabolic activity was assessed via resazurin assay. Statistics: ANOVA/Tukey’s (C. albicans) and Kruskal-Wallis/Mann-Whitney (S. mutans; p* < 0.05).

Results: Light-activated CUR and RB significantly reduced biofilm viability versus controls (p* < 0.05). C. albicans were more susceptible than S. mutans, with RB showing superior antifungal activity (p* < 0.05). CUR exhibited light-independent effects.

Conclusion: aPDT with CUR/RB effectively disrupts oral biofilms, demonstrating dual light-dependent and independent mechanisms. This supports its use as an adjunct for caries and candidiasis management.