Residual activity of cetrimide and chlorhexidine on Enterococcus faecalis-infected root canals

Effective final irrigation regimen is an important step in order to achieve better disinfection and ensure residual antimicrobial effects after root canal preparation. The aim of this study was to compare the residual antimicrobial activity of 0.2% cetrimide, and 0.2% and 2% chlorhexidine in root canals infected with Enterococcus faecalis. Biofilms of E. faecalis were grown on uniradicular roots for 4 weeks. After root canal preparation, root canals were irrigated with 17% ethylenediaminetetraacetic acid (EDTA) to remove the smear layer. The roots were randomly divided into three experimental groups (n=26) according to the final irrigating solution: Group I, 5 mL 0.2% cetrimide; Group II, 5 mL 0.2% chlorhexidine; and Group III, 5 mL 2% chlorhexidine. Samples were collected for 50 days to denote the presence of bacterial growth. The proportion of ungrown specimens over 50 days was evaluated using the nonparametric Kaplan–Meier survival analysis. Differences among groups were tested using the log-rank test and the level of statistical significance was set at P<0.05. The highest survival value was found with 2% chlorhexidine, showing statistically significant differences from the other two groups. At 50 days, E. faecalis growth was detected in 69.23% specimens in Groups I and II, and in 34.61% specimens of Group III. There were no significant differences between 0.2% cetrimide and 0.2% chlorhexidine. Final irrigation with 2% chlorhexidine showed greater residual activity than 0.2% chlorhexidine and 0.2% cetrimide in root canals infected with E. faecalis. Cleaning root canals with chlorhexidine antiseptic leaves a sustained residual antimicrobial effect, research from Spain shows. Root canal surgery carries a high risk of infection: the bacteria Enterococcus faecalis is commonly found following the procedure. Effective irrigation of root canals during root canal treatment disinfects the area and can provide a barrier to future infection by leaving an antimicrobial residue to attack remaining bacteria. To verify the most effective treatment, Carmen Maria Ferrer-Luque and colleagues at the University of Granada compared three irrigation solutions on root canals infected with E. faecalis. After 50 days, the team found significant bacterial growth on 69% of roots treated with weak solutions (0.2%) of cetrimide and chlorhexidine. A more potent chlorhexidine solution (2%), however, indicated a longer-lasting residual effect, with E. faecalis growth on less than 35% of roots.