Efeito da terapia fotodinâmica antimicrobiana frente a diferentes protocolos de agitação do fotossensibilizador na inibição de E. faecalis no sistema de canais radiculares

Abstract

The objective of this study was to evaluate, in vitro, the antibacterial activity of photodynamic therapy associated with different photosensitizer agitation protocols in the fight against Enterococcus faecalis in the root canal system. It was an experimental test, in which a total of 90 single-rooted human premolars were prepared and contaminated with E. faecalis (3 x 108 cel/mL). The teeth were randomly divided into five experimental groups with 15 teeth each, a negative control group with five teeth and a positive control group with ten teeth: Group C+ (Positive control - conventional needle irrigation); Group C – (negative control – no treatment); PDT group (photodynamic therapy); IUP group (2.5% NaOCl ultrasonic agitation), XP-endo group (2.5% NaOCl agitation with XP-endo); PDT + IUP group (Antimicrobial photodynamic therapy + ultrasonic agitation of the photosensitizer); PDT + XP-endo group (Antimicrobial photodynamic therapy + FS agitation with XPendo finisher). The light source used was a low power diode laser, with a wavelength of 660nm, power of 100 mW, energy of 9 J, for 90 seconds of irradiation. The photosensitizer used was 0.005% methylene blue, which remained in the channel for a pre-irradiation period of three minutes. The canal content was collected with sterile absorbent paper points at two moments: before the decontamination protocols, and 24 hours after the protocols. The number of E. faecalis colony forming units (CFU) was determined for each root canal. ANOVA and TUKEY tests were used, and the significance level was set at 5% (p < 0.05). The percentage of growth inhibition ranged from 0.0 (C-) to 62.5 (XP-endo), with different CFU/mL values among all tested protocols (p < 0.05). Percent growth inhibition ranged from 0.0 (C-) to 62.5 (XP-endo). The highest percentages of inhibition were observed in groups G4 (XPendo) (62.5%) and G7 (PDT + XP-endo) (62.4%). After carrying out this study, it was concluded that the agitation of the photosensitizer, either with the use of ultrasound or with XP endo, significantly improved the antimicrobial activity when compared to the PDT group without agitation. There was no significant difference between the agitation methods. Keywords: photochemotherapy; biofilms; enterococcus faecalis; endodontics.