Reduction of Multispecies Biofilms on an Acrylic Denture Base Model by Antimicrobial Photodynamic Therapy Mediated by Natural Photosensitizers.

Objectives: The aim of this study is to investigate the antimicrobial efficacy of antimicrobial photodynamic therapy (PDT) using natural photosensitizers (curcumin, riboflavin, and phycocyanin) and light-emitting diode (LED) irradiation against multispecies biofilms in an acrylic denture base model.

Materials and methods: Forty-five acrylic specimens were fabricated using heat-curing acrylic resin. The specimens were then infected with a mixed culture of bacterial and fungal species (including Streptococcus mutans, Streptococcus sanguinis, Candida albicans, and Candida glabrata) for 4 days. The acrylic discs were divided into nine groups, with each group containing five discs: control, 0.2% chlorhexidine, 5.25% sodium hypochlorite, curcumin, riboflavin, phycocyanin alone or along with LED. After treatment, the number of colony-forming units (CFUs) per milliliter was counted. In addition, the extent of biofilm degradation was assessed using the crystal violet staining method and scanning electron microscopy.

Results: All experimental groups exhibited a significant reduction in colony numbers for both bacterial and fungal species compared to the control (p < 0.001). The PDT groups exhibited a statistically significant reduction in colony counts for both bacteria and fungi compared to the photosensitizer-only groups.

Conclusions: The results of this in vitro study show that PDT with natural photosensitizers and LED devices can effectively reduce the viability and eradicate the biofilm of microorganisms responsible for causing denture infections.