Abstract
Introduction
Enterococcus faecalis is frequently recovered from root-filled teeth with refractory apical periodontitis.
The ability of E. faecalis to form a matrix-encased biofilm contributes to its pathogenicity; however, the role
of extracellular dextran and DNA in biofilm formation and its effect on the susceptibility
of the biofilm to chlorhexidine remains poorly understood.
Methods
E. faecalis biofilms were incubated on dentin blocks. The effect of a dextran-degrading enzyme
(dextranase) and DNase I on the adhesion of E. faecalis to dentin was measured using the colony-forming unit (CFU) counting method. CFU assays
and confocal laser scanning microscopy were used to investigate the influence of dextranase
and DNase I on the antimicrobial activity of 2% chlorhexidine.
Results
The CFU count assays indicated that the formation of biofilms by E. faecalis was reduced in cells treated with dextranase or DNase I compared with that in untreated
cells (P < .05). In addition, we found that treating E. faecalis biofilms with dextranase or DNase I effectively sensitized the biofilms to 2% chlorhexidine
(P < .05).
Conclusions
Both dextranase and DNase I decrease the adhesion of E. faecalis to dentin and sensitized E. faecalis biofilms to 2% chlorhexidine.
Key Words
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Article info
Publication history
Published online: May 21, 2012
Footnotes
Weilan Li and Hongyan Liu contributed equally to this study.
Supported by the Department of Science and Technology of Guangdong Province (2010B050700007, 2009B030801115).
Identification
Copyright
© 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
