In vitro antibiofilm effect of different irradiation doses in infected root canal model

Eradication of endodontic biofilms from the infected root canal system is still the main concern in endodontics. In this study, the role of the power density parameter in the efficacy of antimicrobial photodynamic therapy (PDT) with toluidine blue O (TBO) and phycocyanin (PC) activated by a 635 nm diode laser (DL) against Enterococcus faecalis biofilm in the root canal model was investigated.

The E. faecalis biofilm in the root canal was treated with TBO and PC with different power densities (636, 954, 1273, and 1592 W/cm²). The untreated biofilm represented the control group. After the treatments, the biofilms were analyzed based on the number of colonies per milliliter.

TBO and PC activated with 635 nm DL with a power density of 1592 W/cm² were more efficient in removing E. faecalis biofilms within the root canals than those with a power density of 636 W/cm² (p = 0.00).

The light power density optimized the bacterial reduction of E. faecalis biofilms in the root canal spaces. These results provide information on the decisive parameters for performing PDT on intracanal biofilms.