Efficacy of indocyanine green-mediated photodynamic therapy in the treatment of Candida albicans-penetrated denture base material: an in vitro study

Denture stomatitis is a frequently encountered inflammatory condition among complete denture wearers. Candida species are the principal etiological agents and are capable of colonizing both the denture surface and surrounding oral tissues, as well as infiltrating the denture base material. Effective management necessitates the elimination of microorganisms from both surface and subsurface regions of the denture. Therefore, the aim of the present study was to evaluate the efficacy of indocyanine green (ICG)-mediated photodynamic therapy (PDT) against C. albicans inside acrylic resin. A total of 108 polymethylmethacrylate (PMMA) discs with a radius of 10 mm and thickness of 2 mm were produced. The samples were contaminated with C. albicans . The following nine groups were evaluated: control group (C); nystatin-treated (1 mL, 100.000 IU) group (N); microwave-disinfected (650 W, 3 min) group (M); laser-treated (810 nm, diode laser, continuous mode 30 s, 24 J/cm², 300 mW) group (L); ICG-treated (10 mg/mL) group (ICG10); 10 mg/mL ICG-mediated PDT group (L-ICG10), 5 mg/mL ICG-mediated PDT group (L-ICG5); 2 mg/mL ICG-mediated PDT group (L-ICG2); and 1 mg/mL ICG-mediated PDT group (L-ICG1). After being vortexed, the C. albicans on and in the denture base material were extracted, and the resulting solutions of the samples were inoculated into Petri dishes containing Sabouraud agar media. Colonies of C. albicans biofilms on media were counted with a colony counting device after incubation for 24 h. Eleven samples from each group were used for statistical analysis, and 1 spare sample from each group was used for scanning electron microscopy (SEM). The Kolmogorov‒Smirnov test and the Kruskal‒Wallis test with Bonferroni correction were used for statistical analysis (p˂0.05). L-ICG10, L-ICG5 and ICG10 reduced the number of C. albicans colonies on the denture base material (p˂0.05), whereas the other groups did not significantly differ from the control group ( p > 0.05). C. albicans forms were detected in the SEM images of the cross-sections of all the groups except the L-ICG10 group. Within the limitations of the current study, 10 mg/mL ICG-mediated PDT can be used to decontaminate the denture base from C. albicans .