Journal of Lasers in Medical Sciences

Abstract

Introduction: This in vitro study was conducted to assess the phototoxic effects of curcumin, nanocurcumin, and erythrosine on the viability of Streptococcus mutans (S. mutans) in suspension and biofilm forms.
Methods: Various concentrations of curcumin (1.5 g/L, 3 g/L), nano-curcumin (3 g/L), and erythrosine (100 μM/L, 250 μM/L) were examined for their impact on planktonic and biofilm cultures of S. mutans, either individually or in conjunction with light irradiation (photodynamic therapy or PDT). A blue light-emitting diode (LED) with a central wavelength of 450 nm served as the light source. The results were compared to 0.12% chlorhexidine digluconate (CHX) as the positive control, and a solution containing neither a photosensitizer (PS) nor a light source as the negative control group. The dependent variable was the number of viable microorganisms per experiment (CFU/mL).
Results: Antimicrobial PDT caused a significant reduction in the viability of S. mutans in both
planktonic and biofilm forms, compared to the negative control group (P<0.05). The highest cell
killing was observed in PDT groups with curcumin 3 g/L or erythrosine 250 μmol/L, although the
difference with PDT groups using curcumin 1.5 g/L or erythrosine 100 μmol/L was not significant
(P>0.05). Antimicrobial treatments were more effective against planktonic S. mutans than the
biofilm form.
Conclusion: PDT with either curcumin 1.5 g/L or erythrosine 100 μmol/L may be suggested as an alternative to CHX to inactivate the bacteria in dental plaque or deep cavities. Nanocurcumin, at the selected concentration, exhibited lower efficacy in killing S. mutans compared to Curcumin or erythrosine.