CLINICAL EVALUATION OF THE ANTIMICROBIAL AND ANTI-INFLAMMATORY EFFECTS OF INTRACANNEL MEDICATIONS ASSOCIATED WITH N-ACETYL CYSTEINE

• Grant number: 22/12570-5
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2023
• End date: February 29, 2024
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Marcia Carneiro Valera Garakis
• Grantee: Beatriz Kowalski Fiamini
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

The interaction between microbial factors in root canals with necrotic pulp, and the inflammatory reaction against the invasion of these aggressive agents in the periradicular tissues of the host cause the development, progression and dissemination of apical periodontitis. This randomized clinical study aims to evaluate root canal disinfection and periapical inflammatory process after biomechanical preparation and use of different intracanal medications (MIC), monitoring the profile and bacterial load; endotoxin and lipoteichoic acid (LTA) levels; Inflammatory modulation through the quantification of lipid mediators, resolvin D2 and maresins and IL-10 in teeth with primary endodontic infections and apical periodontitis. This analysis will be performed at different times during endodontic treatment: a) before treatment; b) after biomechanical preparation with a reciprocating file and 2.5% NaOCl solution; c) 14 days after the use of intracanal medications: Ca(OH)2 + serum: calcium hydroxide + physiological saline solution; Ca(OH)2 + NAC: calcium hydroxide + N-acetyl cysteine; and NAC + CHX: N-acetyl cysteine + chlorhexidine. Endotoxin levels, LTA, load and microbial profile will be related to clinical signs and symptoms and periapical lesion volume (mm³), through the use of cone beam computed tomography (CBCT). To achieve the proposed objective, 45 permanent and single-rooted teeth with pulp necrosis and periapical lesion will be submitted to endodontic therapy in multiple sessions. Samples will be collected from inside the canals after accessing the pulp chamber (S1); after biomechanical preparation (S2), and after 14 days of MIC (S3). The collected contents will be analyzed for antimicrobial activity by counting colony forming units (CFU/mL); microbiological profiling by Checkerboard DNA-DNA hybridization; quantification of endotoxins (EU/mL) by the Limulus Amebocyte Lysate - LAL test; and lipoteichoic acid by means of the Enzymatic Immunosorbent Assay (ELISA). Apical interstitial fluid will also be collected after biomechanical preparation (SF1) and after 14 days of intracanal medication (SF2) for quantification of lipid mediators (resolvin D2) and maresin (MaR1), through the Enzymatic Immunosorbent Assay (ELISA) and inflammatory cytokines (IL-1², IL-6, IL-10, IL-17 and TNF-±) by the multiplex assay. All data obtained from the mentioned tests will be tabulated in the GraphPad Prism 8 software, and will be submitted to the statistical normality tests of Kolmogorov-Smirnov and Lilliefors, Kruskal-Wallis and Dunn, and Friedman.