Antibiofilm Activity of Diclofenac and Antibiotic Solutions in Endodontic Therapy

The aim of this study was to compare the antibiofilm effects of a triple antibiotic solution (TAS); a double antibiotic solution (DAS); and 5%, 2.5%, and 1.25% diclofenac solutions (DCSs) against Enteroccocus faecalis biofilm.

Eighty-four sterile radicular dentin blocks were used as biofilm substrate for 3 weeks. The study groups were as follows: (1) 1 mg/mL TAS (minocycline, metronidazole, and ciprofloxacin), (2) 1 mg/mL DAS (metronidazole and ciprofloxacin), (3) 5% DCS, (4) 2.5% DCS, (5) 1.25% DCS, and (6) 0.9% saline solution. The antimicrobial activity was evaluated by bacterial count determinations and confocal laser scanning microscopy. The contact time for the antimicrobial tests was 5 minutes. Bacterial counts were expressed as the reduction percentage of colony-forming units; for the confocal laser scanning microscopic evaluation, the log₁₀ total biovolume and percentage of green population (live cells) were calculated.

The colony-forming unit reduction percentage ranged between 62.98 and 98.62, respectively, for TAS and 5% DCS. The DCS showed a concentration-dependent effect.For the confocal laser scanning microscopy, the log₁₀ total biovolume in all groups was very similar and showed a scarce (1.39-1.02) but significant reduction with respect to the control; 5% and 2.5% DCSs gave the lowest viable cell percentage. The TAS and DAS groups showed intermediate values without significant differences between them.

DCSs at 5% and 2.5% have greater antimicrobial effects than TAS and DAS and may be considered a valid alternative for controlling the infection of teeth with apical periodontitis.