Enterococcus faecalis‐mediated biomineralized biofilm formation on root canal dentine in vitro

Abstract

Enterococcus faecalis is the most predominant bacteria in teeth with failed root canal therapy and is found to survive harsh conditions prevailing in the root canals of endodontically treated teeth. This study aims to investigate the interaction between E. faecalis and root canal dentine substrate. Towards this end, tooth specimens were prepared and divided into two groups. The tooth specimens in group 1 were incubated with E. faecalis for periods of 2-, 4-, and 6-week intervals and the chemical composition of the biofilm was determined using X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. The tooth specimens in group 2 were incubated with E. faecalis for a period of 6 weeks and the topography and ultrastructure of the biofilm were examined using scanning electron microscopy (SEM), light microscopy, and laser confocal scanning microscopy. The sediments formed from the bacterial interaction on the dentine (in group 1) were also examined by SEM and FTIR. These experiments highlighted different stages in the interaction of E. faecalis with root canal dentine. Further, a bacterial-induced apatite reprecipitation on mature biofilm was also observed. This ability of E. faecalis to form such calcified biofilm on root canal dentine may be a factor that contributes to their persistence after endodontic treatment.

Comparative Analysis of Enterococcus faecalis Biofilm Formation on Different Substrates

“…Development of biofilms in vitro has been conducted by using several different types of substrate: human dentin (21,22), bovine dentin (16), bovine dental enamel (23), silicone disks (24), cellulose acetate membranes (25), and hydroxyapatite (14,15). Substrates with complex anatomic configuration lead to formation of irregular biofilm, alternating thicker areas with others that contain sparse bacterial cells.…”

Light activated disinfection: an alternative endodontic disinfection strategy

“…The structure of in vitro biofilm formed by E. faecalis on root canal dentine at different stages of incubation was confirmed by previous studies. 30,31 The cumulative structural and chemical modifications of biofilm with maturation could contribute to its increased resistance to antimicrobial agents. It was shown that the biofilm formed by E. faecalis on root canal dentine was capable of mineralizing, and pockets of viable bacterial cells survived within the mineralized biofilm structure.…”

“…28 Earlier investigations have highlighted the ability of E. faecalis to penetrate into the dentinal tubules and form distinct mineralized biofilm within the root canal. [29][30][31] The objective of this ex vivo study is to evaluate the antibacterial efficacy of different LAD based techniques on immature (four-day-old) and mature (four-week-old) biofilm models of E. faecalis on root canal dentine.…”

Effects of Myrcia ovata Cambess. essential oil on planktonic growth of gastrointestinal microorganisms and biofilm formation of Enterococcus faecalis

“…faecalis is an important opportunistic pathogen having the ability to adhere to biotic and abiotic surfaces allowing the formation of a biofilm that permits to grow and survive in harsh environments prevailing in the root canal (12,14,17). A number of infections caused by E.faecalis strains have proven to be particularly difficult to treat with current antibiotic therapies, partly owing to their intrinsic antibiotic resistance elements, capacity of growing in a biofilm (24).…”