Antimicrobial action of different final irrigation protocols in root canals infected with mixed biofilms: an ex vivo study

Abstract

Objective: To evaluate the antimicrobial action of passive ultrasonic irrigation (PUI) or conventional irrigation (CI) of NaCl 2.5% and 17% EDTA or QMiX after biomechanical preparation on the viability of mixed biofilms and neutralization of endotoxins in root canals ex vivo. Material and Methods: Ninety-six unirradicular human roots with single and straight canal will be selected and infected with C. albicans, E. faecalis and E. coli for 21 days. After confirmation of the contamination, the samples will be instrumented and randomly divided into 8 groups (n = 12) according to the final irrigation protocol with EDTA or QMiX: E1 - CI with NaOCl and EDTA; E2 - PUI with NaOCl and CI with EDTA; E3 - CI with NaOCl and PUI with EDTA; E4 - PUI with NaOCl and EDTA; Q1 - CI with NaOCl and QMiX; Q2 - PUI with NaOCl and CI with QMiX; Q3 - CI with NaOCl and PUI with QMiX; Q4 - PUI with NaOCl and QMiX. Two samples from each group will be prepared for SEM to illustrate the amount of bacterial cells in the root canal walls and dentinal tubules in each group and the others will be used for microbiological analysis and endotoxin quantification. The mean colony-forming units and endotoxin concentration will be determined and compared between groups using two-way ANOVA. (AU)