Influence of passive ultrasonic irrigation on bacterial and endotoxin reduction from root canal system: a randomized clinical study

Abstract

Chemomechanical procedures along sodium hypochlorite (NaOCl) irrigation promote a substantial elimination of microorganisms and endotoxins from root canal; however, almost 50% of the canals still harbor bacteria after chemomechanical debridement, as detected by molecular methods. Therefore, supplementary approaches have been proposed to optimize root canal disinfection; including a passive ultrasonic irrigation (PUI). The purpose of this clinical study is to compare the results of 2 irrigation protocols, PUI and standard irrigation, in obtaining bacterial and endotoxin reduction from root canals. A total of 50 patients requiring endodontic therapy of teeth with apical periodontitis will be recruited for the study. The patients will be randomly distributed in 2 groups, according to the irrigation protocol to be used during the therapy: PUI - Passive Ultrasonic Irrigation (n=25) and standard irrigation (n=25). The chemomechanical preparation will be performed with rotary nickel-titanium instruments. The irrigant used during instrumentaion will be NaOCl 2.5%; and EDTA 17% will be used to remove smear layer. The root canals were filled with calcium hydroxide for 14 days and then the canals will be obturated. Samples will be taken before (S1) and after preparation (S2); after the different irrigation prorocols (S3); and after intracanal medication (S4). Quantitative PCR (Real Time PCR) will be used to quantify the reduction of the bacterial load after disinfection. The Limulus amebocyte lysate (LAL) assay will be used for the quantification of endotoxins. Statistical analysis will be performed on treatment group and outcome of microbiologic tests to evaluate for significance. (AU)