Comparative Analysis of Enterococcus faecalis Biofilm Formation on Different Substrates

IntroductionThe aim of this study was to compare Enterococcus faecalis biofilm formation on different substrates.MethodsCell culture plates containing growth medium and E. faecalis (ATCC 29212) were used to grow biofilm on bovine dentin, gutta-percha, hydroxyapatite, or bovine bone. Substrates were incubated at 37°C for 14 or 21 days, and the medium was changed every 48 hours. After the growth induction periods, specimens (n = 5 per group and per induction period) were stained by using Live/Dead, and the images were analyzed under a confocal microscope. The total biovolume (μm3), live bacteria biovolume (μm3), and substrate coverage (%) were quantified by using the BioImage_L software. Results obtained were analyzed by nonparametric tests (P = .05).ResultsBiofilm formation was observed in all groups. Gutta-percha had the lowest total biovolume at 14 days (P < .05) and hydroxyapatite the highest at 21 days (P < .05). No significant difference was observed in green biovolume at 14 days. At 21 days, however, hydroxyapatite had the highest volume (P < .05). The percentages of coverage were similar among all substrates at 21 days (P > .05), but at 14 days, bovine bone presented the highest coverage (P < .05).ConclusionsE. faecalis was capable of forming biofilm on all substrates during both growth periods; hydroxyapatite presented the highest rates of biofilm formation. The type of substrate influenced the biofilm characteristics, according to the parameters evaluated.