Efficacy of antimicrobial photodynamic therapy with chitosan nanoparticles for decontamination of dental implants contaminated with Aggregatibacter actinomycetemcomitans.

This study aimed to assess the efficacy of antimicrobial photodynamic therapy (aPDT) with chitosan nanoparticles (CNPs) for decontamination of dental implants inoculated with Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans). In this in vitro study, CNPs containing indocyanine green (ICG) were synthesized and characterized. Sandblasted large-grit acid-etched (SLA) titanium implants (n = 54) were inoculated with A. actinomycetemcomitans, and randomly assigned to 6 groups (n = 9) for decontamination: (I) negative control (PBS rinse for 60 s), (II) positive control [exposure to 0.2% chlorhexidine (CHX) for 5 min], (III) exposure to 0.25 mg/mL ICG at 37 °C for 5 min, (IV) exposure to 0.25 mg/mL ICG followed by 808 nm diode laser irradiation for 60 s, (V) exposure to 0.25 mg/mL ICG-loaded CNPs, (VI) exposure to 0.25 mg/mL ICG-loaded CNPs followed by 808 nm diode laser irradiation for 60 s. The A. actinomycetemcomitans colonies were counted, and data were analyzed by one-way ANOVA and Tamhane test (alpha = 0.05). The test groups showed a significant reduction in colony count compared to the negative control (P < 0.05). Laser plus ICG-loaded CNPs and CHX had comparably the highest decontamination efficacy. This study demonstrated that aPDT with ICG-loaded CNPs significantly reduced the A. actinomycetemcomitans colony count on dental implants, showing comparable efficacy to CHX.