Antibiofilm activity of irrigating solutions associated with cetrimide. Confocal laser scanning microscopy

To evaluate the antibiofilm activity of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) solutions associated with cetrimide (CTR), and QMiX using confocal laser scanning microscopy.

Enterococcus faecalis (ATCC- 29212) biofilms were induced on bovine dentine blocks for 14 days. The dentine blocks containing biofilm were immersed for 1 min in the following solutions: 2.5% NaOCl; 2.5% NaOCl + 0.2% CTR; 2% CHX; 2% CHX + 0.2% CTR; 0.2% CTR; QMiX. After contact with the solutions, the dentine blocks were stained with Live/Dead(®) BacLight for analysis of the remaining biofilm using confocal laser scanning microscope. Images were evaluated using the BioImage_L software to determine the total biovolume (μm(3) ), the green biovolume (live cells) (μm(3) ) and the percentage of substrate coverage (%). The data were subjected to nonparametric statistical test using Kruskal-Wallis and Dunn's tests at 5% significance level.

After exposure to irrigants, the total biovolume observed for CHX, CHX+CTR, CTR, QMiX was similar to distilled water (P > 0.05). NaOCl and NaOCl+CTR had the lowest total and green biovolume. The CTR and QMiX had intermediate green biovolume, with greater antibacterial activity than CHX and CHX+CTR (P < 0.05). The NaOCl and NaOCl+CTR solutions were associated with microorganism removal and substrate cleaning ability.

NaOCl and NaOCl+CTR solutions were effective on microorganism viability and were able to eliminate biofilm. The addition of cetrimide did not influence antibacterial activity.