Anticandidal Efficacy of Erythrosine with Nano-TiO2 and Blue LED-Mediated Photodynamic Therapy against Candida albicans Biofilms on Acrylic Resin: A Preliminary Study

Objective: Incorporating an enhancer such as nano-titanium dioxide into antimicrobial photodynamic therapy can improve treatment outcome. This study aimed to compare the anticandidal efficacy of photodynamic therapy by erythrosine with nano-titanium dioxide (nano-TiO2) stimulated by a blue light emitting diode with three standard dental antifungal agents. Materials and methods: Candida albicans biofilms on acrylic resin plates were treated for 15 minutes with either nystatin, fluconazole, Polident, 220 mu M erythrosine + 1% (w/w) nano-TiO2 + 15 J/cm(2) blue light photodynamic therapy (Ery PDT), or distilled water. For the Ery PDT group, blue light was applied for 1 minute after incubation. After 1, 3, and 6 hours, the colony forming units in log10 (log(10)CFU/mL) were compared. The ultrastructure of C. albicans on the acrylic resin plates treated with erythrosine + nano-TiO2 + blue light was examined using transmission electron microscopy at magnification of 30,000x. Results: After 1 hour, nystatin, Polident, and Ery PDT indifferently inhibited C. albicans. At 6 hours, Ery PDT reduced the number of viable C. albicans in biofilms by 0.28log(10) CFU/mL, which was equal to the effect of fluconazole and Polident. Transmission electron microscopy demonstrated that Ery PDT altered the C. albicans cell morphology by inducing cell wall/membrane rupture. Conclusion: Photodynamic therapy with erythrosine + nano-TiO2 + blue light at low light power density (15 J/cm(2)) was as effective at inhibiting C. albicans biofilm on acrylic resin as fluconazole and Polident.