IN VITRO EVALUATION OF AMBROXOL HYDROCHLORIDE AS AN ALTERNATIVE IRRIGANT IN REGENERATIVE ENDODONTIC PROCEDURES: ANTIMICROBIAL, ANTI-BIOFILM, AND DENTINAL ULTRASTRUCTURAL EFFECTS ANALYSIS

• Grant number: 24/18863-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2025
• End date: August 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Marco Antonio Hungaro Duarte
• Grantee: Letycia Accioly Simões Coelho
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Associated research grant: 23/01051-0 - Development and analysis of new irrigators and protocols for use in revascularization and pulp regeneration procedures, AP.R
• Associated scholarship(s): 25/06358-1 - Irrigation with Ambroxol Hydrochloride and Disodium EDTA in Regenerative Procedures: Effect on Growth Factor Expression, BE.EP.DR

Abstract

The efficacy of regenerative endodontic procedures depends on the disinfection of the environment, which is achieved solely through chemical solutions. The combined use of low concentrations of sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA) has been recommended for the cleaning and disinfection of immature necrotic tooth canals. However, studies have shown that NaOCl has deleterious effects on stem cells and the dentin matrix, and 17% EDTA has low antimicrobial efficacy. Therefore, the objectives of this research will be to evaluate, in vitro, the use of Ambroxol Hydrochloride and 15% disodium EDTA, alone or combined with different irrigant solutions and when ultrasonic or pulsed laser activation is used, focusing on: 1) Antimicrobial and anti-biofilm action, and 2) Ultrastructural effects on dentin. For all tests performed, the specimens will be divided into 9 groups (G1-G9) according to the irrigation protocol and further subdivided based on the irrigation method (n=3): conventional syringe and needle irrigation (SG1), ultrasonic agitation (SG2), and Thera Lase Surgery laser agitation (SG3). To assess the antimicrobial capacity (n=8), 8 bovine incisors per group will be selected and prepared for antimicrobial tests in dentinal tubules and anti-biofilm tests for Enterococcus faecalis and Streptococcus mutans. To evaluate the ultrastructural effects on dentin (n=3), a prototyped tooth will be prepared, creating a site similar to a trephine bur for fitting bovine dentin blocks. Then, irrigation protocols will be carried out using a closed system, and the amide III/phosphate and carbonate/phosphate (PO3-)/(CO3-) ratios will be determined through FTIR analysis, and scanning electron microscope images will be obtained. The Shapiro-Wilk normality test will be applied, followed by a parametric or non-parametric test, with a significance level of 5%.