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

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. 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. 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). 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.