Developing a customised flow cell biofilm model to evaluate various root canal irrigants against the Enterococcus faecalis biofilm - An in vitro study

Aim: The aim of the study was to construct a customized flow cell biofilm apparatus for the formation of Enterococcus faecalis biofilm and evaluate the effect of various root canal irrigants against the E. faecalis biofilm. Methods: Five customized flow cell apparatus were developed to grow E. faecalis biofilm. A total of 35 single-rooted mandibular premolars were selected. Coronal sectioning followed by root canal preparation using the Protaper universal system till size F1 was done. Samples were sectioned buccolingually. A total of 14 root sections were added to one-flow cell biofilm apparatus. All the five apparatuses were allowed to run for 7 days. After 7 days, root sections were removed and placed in 300 mL of appropriate irrigation solutions, namely, Group 1, saline; Group 2, chlorhexidine; Group 3, neem extract; Group 4, moringa extract; and Group 5, neem and moringa extract. A final rinse was performed with distilled water. Four root sections from each group were streaked in four different agar plates, and the total colony-forming units (CFUs) were counted. The remaining root sections were analyzed by a confocal laser scanning microscope and a scanning electron microscope for the mean live and dead bacterial count. Results: The total CFUs indicated that the customized biofilm model developed a significant amount of biofilm on all the samples ranging from 1.00 × 10 4 CFU/mL to 3.36 × 10 4 CFU/mL. The mean live and dead bacterial counts showed that chlorhexidine had a significant bactericidal effect against E. faecalis ( P < 0.05). Conclusion: The proposed customized in vitro biofilm apparatus developed E. faecalis biofilm. Chlorhexidine showed a significant antibacterial effect against E. faecalis biofilm. This customized flow cell biofilm apparatus will be a useful tool for biofilm research in analyzing various endodontic and cariogenic microbiology.