Primary versus secondary endodontic infection: inflammatory and lipidic profile, microbial load, endotoxin and lipoteichoic acid levels before and during the root canal therapy and success after 18 months follow-up.

Abstract

The aim of this study are: a) to quantify endotoxins (EU/mL), lipoteichoic acid (LTA) and microbial load in teeth with primary and secondary endodontic infections, before and after biomechanical preparation and after the use of different intracanal medications; b) to analyze the levels of IL-1, IL-6, IL-10 and TNF-±, Resolvina E1, Resolvina E2 and Lipoxin A4 of the interstitial fluid in primary endodontic infections with the use of different medications; c) to monitor and relate levels of endotoxin (EU/mL), LTA and microbiological load (CFU/ mL) the periapical lesion volume in cases of secondary endodontic infection treated in single or multiple visits and correlate these data with the volume of the periapical lesion and with clinical signs and symptoms; d) to compare the success of endodontic treatment in cases of secondary endodontic infection after 18 months, performed in single and multiple visits. Sixty teeth with pulp necrosis and periapical lesion will be selected, being 36 teeth with primary infection and 24 teeth with secondary infection. After coronary opening, initial collection will be performed to verify the presence of infection in the root canals. Then, endodontic treatment will be performed using 2.5% NaOCl solution and Reciproc reciprocating system (VDW, Munich, Germany) and the teeth divided into 5 groups according to the treatment protocol: I) treatment of teeth with primary endodontic infection: i) endodontic treatment: G1- Ca (OH)2: calcium hydroxide PA + physiological saline; G2 - Ca (OH) 2 + CLX: calcium hydroxide PA + chlorhexidine gel 2%, G3 - NAC + SS: N - acetylcysteine + physiological saline solution and II) endodontic retreatments: G4 - and G5 - multiple session retreatment with Ca (OH) 2 PA + physiological saline (MR) medication. Root canal collections will be performed after biomechanical preparation, removal of the intracanal medication and after foraminal enlargement. For all the collections, tests of antimicrobial activity by microbiological culture (CFU/mL), analysis of endotoxin levels (EU/mL) by Limulus amebocyte lysate, detection and quantification of lipoteichoic acid (LTA) by ELISA method and analysis of the presence of cytokines by ELISA will be perfomed. Volumetry of periapical bone destruction will be performed through CBCT analysis using Nemotec® software for the retreatment groups. In addition, a 18 months follow up will be performed to compare periapical volume in the single and multiple visits groups in cases of secondary endodontic infection. All data will be analyzed statistically. (AU)