An in vitro study on the efficacy of hydrogen peroxide mediated high-power photodynamic therapy affecting Enterococcus faecalis biofilm formation and dispersal

Objective: Biofilms are involved in failure of root canal treatment due to their high resistance to antimicrobial agents, which make their removal as a big challenge. The present study aims at utilizing hydrogen peroxide (HP) plus high frequency laser reinforced antimicrobial photodynamic therapy (a-PDT) as a complementary therapy against Enterococcus faecalis (E. faecalis) at planktonic and biofilm stages.Materials and methods: E. faecalis at planktonic and biofilm stages was treated with the photosensitizer HP, fol-lowed by no irradiation or irradiation with a power of 2.5 W (lambda = 980 nm). The cell viability, anti-biofilm, anti-metabolic potential, and temperature changes were evaluated.Results: The combination of HP and 980 nm diode laser intensely boosted antibacterial and anti-biofilm efficacy compared with either component alone, affirming HP reinforcement as a bacteriostatic agent. The maximum effect on biofilm occurs in 5.25% sodium hypochlorite (NaOCl) group. During laser irradiations, the mean of temperature changes remains below 5.6 degrees C.Conclusions: It could be concluded that the HP could improve anti-biofilm efficacy as a photosensitizer in a-PDT.