Influence of EDTA and its Association with Benzalkonium Chloride on Enterococcus faecalis Adhesion to Dentin / Influencia del EDTA y su Asociación con Cloruro de Benzalconio en la Adhesión de Enterococcus faecalis a la Dentina

ABSTRACT: The aim of this in vitro study was to investigate the influence of ethylenediaminetetraacetic acid (EDTA) associated with the benzalkonium chloride (BAK) on the adhesion and formation of Enterococcus faecalis biofilms attached to coated dentin. Discs standard bovine dentin blocks were treated with the coating materials evaluated: Saline solution (control), 17 % EDTA, 17 % EDTA associated with 1 % BAK for 5 minutes and subsequently washed with saline solution. Afterwards, biofilms of E. faecalis (ATCC 29212) were grown on the surface of coated dentin blocks for time intervals of 1 hour and 7 days (n = 20) and were subsequently washed with phosphate-buffered saline (PBS). Bacterial viability and total biovolume were analyzed by confocal laser scanning microscopy (CLSM) using the Live/Dead technique. Nonparametric Kruskal-Wallis followed by Dunn tests were used to determine statistical differences (a = 5 %). The 17 % EDTA + 1 % BAK group showed significantly lower biovolume and bacterial viability values at the end of 1 hour (p < 0.05). After 7 days of contamination, the 17 % EDTA and 17 % EDTA + 1 % BAK groups showed similar results that differed statistically from those of the control group (p < 0.05). The saline solution group showed higher values. The use of BAK associated with EDTA on dentin blocks surfaces before exposure to contamination was able to interfere in the adhesion of E. faecalis to dentin. Also, dentin treatment by BAK associated with a chelating agent influences the secondary biofilm formation, which could have important effects on the long-term success of root canal treatment.

RESUMEN: El objetivo del estudio consistió en investigar in vitro, la influencia del ácido etilendiamino-tetraacético (EDTA) con cloruro de benzalconio (BAK) en la adhesión y formación de biopelículas de Enterococcus faecalis a la dentina. Discos de dentina bovina fueron tratadas con solución salina (control), 17 % de EDTA, 17% de EDTA asociado con 1 % de BAK durante 5 minutos y lavadas con solución salina. Las biopelículas de E. faecalis (ATCC 29212) se cultivaron sobre los discos de dentina durante intervalos de tiempo de 1 hora y 7 días (n = 20), lavados con solución salina tamponada con fosfato (PBS). La viabilidad bacteriana y el biovolumen total se analizaron mediante microscopía de barrido por láser (CLSM) utilizando la técnica Live / Dead. Se realizó prueba no paramétrica de Kruskal-Wallis, seguida por Dunn con una diferencia estadística (a = 5 %). El grupo de 17 % EDTA + 1 % BAK mostró valores significativamente menores de biovolumen y viabilidad bacteriana al final de 1 hora (p < 0,05). Después de 7 días de contaminación, los grupos de 17 % EDTA y 17 % EDTA + 1 % BAK mostraron resultados similares que diferían estadísticamente del grupo control (p < 0,05). La solución salina mostró valores más altos. La asociación de BAK con EDTA antes de la contaminación interfirió en la adhesión de E. faecalis. Además, el tratamiento de la dentina por BAK asociado con EDTA influye en la formación de biopelículas secundarias, lo que podría tener efectos importantes sobre el éxito a largo plazo del tratamiento del conducto radicular.

Effect of the irrigation protocols on the elimination of dentin debris from simulated lateral canals / Efeito do método de irrigação na eliminação de debris dentinários em canais late-rais simulados

Objective: Computed microtomography was used to evaluate the capacity of debris removal from simulated lateral canals, in conventional irrigation, passive ultrasonic irrigation (PUI), continuous passive irrigation (CUI), Endoactivator and EasyClean, for both types of motion (continuous and reciprocating). Material and Methods: Sixty acrylic incisors with 3 simulated lateral canals per tooth (cervical, middle and apical third) were instrumented with Reciproc 40/06 and then filled with dentin debris. The teeth were scanned and divided into 6 groups (n = 10) according to the irrigation protocol: G1 - conventional, G2 - PUI, G3 - CUI, G4 - Endoactivator, G5 - EasyClean continuous rotation and G6 - EasyClean reciprocating. After the irrigation protocols, the samples were scanned again. The initial and final volume images were analyzed and the percentage of debris removal were found for each group in all levels. Results: There were significant differences between the initial and final volume of debris after the protocols, with the exception of conventional irrigation group in the apical and cervical thirds, EasyClean reciprocating in the middle and cervical thirds, and CUI in the middle third. In the analysis between the groups: in the apical third, Endoactivator and PUI removed more debris than CUI (p < 0.05); in the middle and cervical thirds, PUI was more efficient than conventional irrigation, EasyClean reciprocating and CUI (p < 0.05). Conclusion: No method completely removed the debris. PUI was the method that showed greater effectiveness in cleaning the lateral canals. (AU)

Objetivo: O objetivo desse estudo foi avaliar a capacidade de remoção de debris de canais laterais simulados através da microtografia computadorizada (microCT), na irrigação convencional, ultrassônica passiva (IUP), ultrassônica contínua (IUC), Endoactivator e EasyClean, para os dois tipos de movimento (contínuo ou alternado). Material e Métodos: Sessenta incisivos de acrílico com três canais late-rais simulados por dente (terço cervical, médio e apical) foram instrumentados com Reciproc 40/06 e preenchidos com debris de dentina bovina. Os dentes fo-ram escaneados e divididos em 6 grupos (n = 10): G1 - convencional, G2 - IUP, G3 - IUC, G4 - Endoactivator, G5 - EasyClean rotação continua e G6 - EasyClean reciprocante. Depois do protocolo de irrigação, as amostras foram novamente escaneadas. O volume inicial e final das imagens foram analisados e o percentual de debris removidos foram encontrados para cada grupo nos três terços. Resultados: Todos os grupos obtiveram diferenças significantes após o proto-colo de irrigação, com exceção do grupo da irrigação convencional nos terços apical e cervical, EasyClean reciprocante (médio e cervical) e IUC no terço médio. Na análise intragrupo para o terço apical, EndoActivator e IUP removeram mais debris que IUC (p<0,05); no médio e cervical, IUP foi mais eficiente que a irrigação convencional, EasyClean reciprocante e IUC (p<0,05). Conclusão: Nenhum método foi capaz de remover completamente os debris. A irrigação ultrassônica passiva foi a que demonstrou melhor efetividade na limpeza dos canais laterais. (AU)