Microbiology

Microbiology

Microbiology

Inhibitory activity of root canal irrigants against Candida albicans, Enterococcus faecalis and Staphylococcus aureus
Tatiana Kelly da Silva Fidalgo(a) Roberta Barcelos(b) Maristela Barbosa Portela(c) Rosangela Maria de Araújo Soares(d) Rogério Gleiser(c) Fernando Costa e Silva-Filho(e)

(a)

School of Dentistry of Rio de Janeiro, Federal University of Rio deJaneiro, Rio de Janeiro, RJ, Brazil. Department of Specific Formation, School of Dentistry, Fluminense Federal University, Nova Friburgo, RJ, Brazil. Department of Pediatric Dentistry and Orthodontics, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil. Professor Paulo de Goes Institute of Microbiology, University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

(b)

(c)

(d)

(e)

Abstract: The present study evaluated the antimicrobial activity of three root canal irrigants against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. These microorganisms were incubated in the presence of citric acid (6 and 10%), EDTA (17%),and NaOCl (0.5, 1.0, 2.5, and 5.25%). Agar diffusion tests were performed and redox indicator resazurin was used to evaluate the inhibitory effect of the irrigants on the metabolic activity of these microorganisms. The mean diameters of the inhibition zones for the C. albicans cultures were 11.6 mm (17% EDTA), 5.5 mm (0.5% NaOCl), 12.9 mm (1% NaOCl), 22.1 mm (2.5% NaOCl), and 28.5 mm (5.25%NaOCl). The mean diameters of the inhibition zones for E. faecalis were 2.8 mm (1% NaOCl), 5.4 mm (2.5% NaOCl), and 8.3 mm (5.25% NaOCl). For S. aureus, the mean values were 8.0 mm (17% EDTA), 3.0 mm (1% NaOCl), 8.8 mm (2.5% NaOCl), and 10.0 mm (5.25% NaOCl). Most of the irrigant solutions presented effective antimicrobial activity against C. albicans. A high inhibitory effect on the metabolic activityof E. faecalis was detected when the microorganisms were incubated with 17% EDTA. The same result was reached when S. aureus was incubated in the presence of ≥ 2.5% NaOCl. Altogether, these results indicate that 2.5% and 5.25% NaOCl are microbicides against S. aureus while 0.5% and 1% NaOCl are only microbiostatic against the tested bacteria. The 6% and 10% citric acid as well as 17% EDTA did notaffect the viability of any of the assayed microorganisms. Descriptors: Candida albicans; Enterococcus faecalis; Staphylococcus aureus; Root Canal Irrigants.

Introduction
Corresponding author: Tatiana Kelly da Silva Fidalgo Rua Joaquim Távora 244/202 - Icarai Niterói - RJ - Brazil CEP: 24230-541 E-mail: tatiana_kelly@yahoo.com.br

Received for publication on Feb 06, 2010 Accepted forpublication on Aug 09, 2010

Microorganisms are the major causative factor associated with endodontic treatment failure.1,2 The success of endodontic treatment depends on the reduction or elimination of bacteria present in the root canal system. Residual pulpal tissue, bacteria, and dentine debris may persist in the irregularities of root canal systems, even after meticulous mechanical preparation.3Therefore, irrigant solutions should be used in combination with canal preparation.4-6 Root canal irrigants are used during chemomechanical procedures not only as antimicrobial agents but also to flush out loose debris, to lubricate the dentinal walls, and to dissolve organic compounds in the

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Braz Oral Res. 2010 Oct-Dec;24(4):406-12

Fidalgo TKS, Barcelos R, Portela MB, Soares RMA,Gleiser R, Silva-Filho FC

canal.7,8 Chemomechanical preparation is one of the most important phases of endodontic treatment and irrigants such as sodium hypochlorite (NaOCl), citric acid, and ethylene diamine tetra-acetic acid (EDTA) are commonly used. The efficacy of these procedures also depends upon the vulnerability of the species involved.9 Many in vitro studies relate the antimicrobial...