ACTION OF ER:YAG LASER AND DIFFERENT CONCENTRATIONS OF SODIUM HYPOCHLORITE ON BACTERIAL BIOFILM AND ON LPS

Abstract

The in vitro study proposes to evaluate the antimicrobial and endotoxin activityof different concentrations of sodium hypochlorite (NaOCl) solution associated with Er:YAG laser activation inside contaminated root canals. Eighty human teeth will have their crowns cut and the roots will be embedded in 24-well plates. The canals will be contaminated with Enterococcus faecalis and Escherichia coli and their endotoxin for 28 days. Afterwards, they will be dividedinto 8 groups (n=10) according to the irrigation protocol to be used: Control: irrigation with saline solution (SS) without activation; Er:YAG: irrigation with SS and activation with Er:YAG tip; NaOCl 1%: irrigation with NaOCl 1% withoutactivation; NaOCl 2.5%: irrigation with NaOCl 2.5% without activation; NaOCl 5.25%: irrigation with NaOCl 5.25% without activation; Er:YAG+NaOCl 1%:irrigation with NaOCl 1% and intracanal activation with Er:YAG; Er:YAG+NaOCl 2.5%: irrigation with NaOCl 2.5% and intracanal activation with Er:YAG;Er:YAG+NaOCl 5.25%: irrigation with NaOCl 5.25% and intracanal activation with Er:YAG. The canals will be instrumented with a reciprocating instrument and irrigation according to the experimental group. Instrumentation will beperformed with the crown-down technique, standardizing the volume of irrigating solution and activation technique. Collections will be made from the inside of the root canals after root canal contamination (S1), after instrumentation (S2) and 7 days after instrumentation (S3). The collected contents will be subjected to microbiological analysis (CFU/mL) and endotoxinanalysis (EU/mL). The results will be analyzed using the Kruskal-Wallis and Dunn tests, significance 95%.