Root canal disinfection is one of the main factors governing success of endodontic
therapy. Antimicrobial photodynamic therapy (aPDT) is presented as a promising
antimicrobial therapy that can eliminate microbiota present in infected root canal
systems. In this study, a series of experiments investigated the effects of aPDT on cell
viability and biofilm degradation ability of endopathogenic microbiota. Enterococcus
faecalis and Pseudomonas aeruginosa strains as the versatile pathogenic microbiota in
endodontic infections were used as the tested strains. Curcumin (CUR) and lightemitting
diode (LED) were used as the photosensitizer and light source, respectively.
The antimicrobial and anti-biofilm effects of CUR-aPDT were assessed by colony
forming unit (CFU), and crystal violet assays. CUR-aPDT significantly decreased the
CFU/mL count of E. faecalis and P. aeruginosa compared to the control group (P<0.05).
The killing percentage of aPDT was achieved 95.0% for E. faecalis and 81.1% for P.
aeruginosa. In addition, the biofilm degradation ability of E. faecalis and P. aeruginosa
significantly decreased to 41.2% and 30.2%, respectively (P<0.05). According to the
results, neither CUR nor LED showed the antimicrobial and anti-biofilm effects when
used alone. In conclusion, the results of this study indicated that CUR-aPDT has an
appreciable effect on endopathogenic microbiota upon photoactivation.