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In mixed biofilms Enterococcus faecalis benefits from a calcium hydroxide challenge and culturing
Author(s) -
Waal S. V.,
Connert T.,
Crielaard W.,
Soet J. J.
Publication year - 2016
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12542
Subject(s) - enterococcus faecalis , biofilm , calcium hydroxide , microbiology and biotechnology , root canal , sodium hypochlorite , pseudomonas aeruginosa , chlorhexidine , enterococcus , biology , chemistry , bacteria , staphylococcus aureus , medicine , antibiotics , dentistry , organic chemistry , genetics
Aim To evaluate the fate of Enterococcus faecalis in dual‐species and multispecies biofilms after treatment with calcium hydroxide (Ca( OH ) 2 ). Methodology Biofilms were cultured from laboratory strains of E. faecalis and Pseudomonas aeruginosa , or from microbiota retrieved from primary root canal infections. The biofilms were then treated with Ca( OH ) 2 . The proportion of E. faecalis and P. aeruginosa and their susceptibility to disinfection were evaluated in a viability assay. In the mixed‐species assay, the presence and proportions of E. faecalis before and after Ca( OH ) 2 treatment were evaluated with a quantitative polymerase chain reaction assay. Groups were compared using Mann–Whitney U‐test and Student's t‐tests. An α <0.05 was considered statistically significant. Results After Ca( OH ) 2 treatment in dual‐species biofilms, the proportion of E. faecalis had increased ( P < 0.001), whereas the total number of CFU s per biofilm was equal. Enterococcus faecalis was equally susceptible to disinfection by sodium hypochlorite (Na OC l) or by chlorhexidine. Pseudomonas aeruginosa had become more susceptible to Na OC l disinfection. The root canal isolates contained no detectable amounts of E. faecalis . After biofilm culturing or Ca( OH ) 2 treatment, it appeared that E. faecalis must have been present in 5 of 6 (83%) root canal samples. Conclusions Calcium hydroxide favours the population of E. faecalis in a dual‐species biofilm. Culturing multispecies root canal isolates makes E. faecalis detectable. E. faecalis was often present in primary endodontic infections, albeit in low numbers.