Antibacterial activity of blue high-power light-emitting diode-activated flavin mononucleotide against Staphylococcus aureus biofilm on a sandblasted and etched surface

Background: Because of high affinity to the titanium implant surface, Staphylococcus aureus (S. aureus) has been reported as key microorganism that cause the peri-implantitis, even though it is not the typical periodontal pathogenic bacterial strain. The aim of this study was to evaluate the antibacterial property of the aPDT device, using blue high-power LED light activated flavin mononucleotide, comparing to the previously proven aPDT method using methylene blue and red laser on S. aureus biofilm. Methods: Commercial pure titanium grade 4 modified surface with SLA were used to form S. aureus biofilm for 48 h. Two aPDT systems were used in this study; 1) HELBO (R) Blue Photosensitizer (Bredent medical), which is methylene blue (MB) activated by 670-nm red diode laser and 2) FotoSan (R) Blue agent Gel (CMS Dental), which contains flavin mononucleotide (FMN) activated by FotoSan (R) BLUE LAD (Light Activated Disinfection) light. The antibacterial tests were performed by total viable count, crystal violet assay, and direct observation methods. Results: Using the light activated-PS, the log reduction in CFU/mL compared to non-treatment was 1.23 +/- 0.19 log(10) and 1.23 +/- 0.12 log(10) (about 93 % of reduction) for MB and FMN, respectively. The significant difference in the reduction could be determined when comparing with using only light (p < 0.01). Regarding two aPDT systems, the decrease in amount of bacteria after treatment was not significantly different (p > 0.05). Conclusion: The antibacterial activities of aPDT using blue high-power LED light activated flavin mononucleotide on S. aureus biofilm was comparable to those of previous research supporting aPDT using photoactivated MB.