In vitro evaluation of Enterococcus faecalis biofilm with laser fluorescence after exposure to endodontic irrigants

Abstract

The aim of this study was to evaluate the performance of the DIAGNOdent Pen (KaVo, Biberach, Germany) with respect to the fluorescence detection and quantification of microorganisms after the use of root canal solutions. Forty roots from extracted bovine incisors were divided into four groups (n = 10) according to the contamination time (7 or 14 days) and irrigating solution (5.25% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX)). Prior to contamination, the fluorescence of root dentin were evaluated at three depths (3, 8, and 12 mm). The roots were autoclaved and contaminated with Enterococcus faecalis (E. faecalis). After contamination and the use of irrigating solutions, the number of colony-forming units (CFUs) and the fluorescence were determined. The number of CFUs obtained in 14-day biofilms was higher (P < 0.05). The fluorescence values were higher for 14-day biofilms than 7-day biofilms in the medium and apical thirds and at baseline (no contamination) (P < 0.05). The 2% CHX produced a greater reduction in the fluorescence values in 7-day biofilms (P < 0.05). The DIAGNOdent pen was able to detect and quantify different levels of fluorescence after the use of root canal solutions. Chemical solutions were effective in reducing the microbial load in biofilms of E. faecalis.