Effectiveness of resveratrol as a root canal irrigation solution in inhibiting biofilm and bacterial metabolic activity of Enterococcus faecalis

Photodynamic therapy is a promising alternative to standard antimicrobial intracanal cleaning and shaping. The potential of resveratrol, a natural phytoalexin, as a photosensitizing and antibacterial agent for endodontic therapy remains uninvestigated. The aim of this study was to assess the effects of resveratrol, either alone as a root canal irrigation solution or activated with a diode laser, on Enterococcus faecalis (E. faecalis) biofilms, focusing on its antibiofilm and bacterial metabolic activities. Mandibular premolars were inoculated with E. faecalis for four weeks and subsequently disinfected using one of five methods (NaCl (0.9%); NaOCl (2.5%); resveratrol (128 µg/mL); resveratrol with diode laser (940 nm); diode laser). Microbial counts were measured before and after disinfection using colony-forming units. Dehydrogenase enzyme activity and polysaccharide synthesis of E. faecalis were also evaluated. Disinfection with the resveratrol with diode laser and NaOCl showed significantly greater bacterial reduction than the other disinfection protocols (p<0.001). No significant differences in dehydrogenase activities among the disinfection protocols (p>0.05). The lowest amount of polysaccharide was found in the resveratrol with diode laser group (p<0.001). The photoactivation of resveratrol with a diode laser may serve as an effective therapeutic strategy for reducing bacterial load and inhibiting polysaccharide formation.