Desenvolvimento de um gel de quitosana com carvacrol para tratamento endodôntico

Abstract

Endodontic research aims to improve root canal treatment, focusing on strategies such as intracanal medication between sessions. The recolonization of the root canal system by microorganisms such as Enterococcus faecalis, Enterococcus faecium, Streptococcus sp., and Candida albicans presents a challenge in preventing endodontic reinfection and maintaining periapical lesions. Carvacrol, extracted from essential oils, is studied for its antimicrobial and antioxidative properties. This study develops a chitosan-based intracanal gel containing carvacrol. MTT assays for cytotoxicity, reactive oxygen species (eROS) assays, and nitric oxide (NO) quantification for antioxidant potential, minimum inhibitory concentration (CIM) for antimicrobial activity, microbial growth curves, cell envelope action, and antibiofilm activity at different stages of biofilm formation were performed. Amoxicillin was used as the positive control. The results showed that carvacrol was not cytotoxic to BALB/c mice peritoneal macrophages and L929 fibroblasts, except at a concentration of 300 μg/mL. Carvacrol demonstrated antioxidant activity starting at 150 μg/mL, as measured by ROS and NO assays. The MIC of carvacrol ranged from 100 to 200 μg/mL, with more pronounced antibiofilm activity in pre-formed biofilms and less efficacy during the adhesion phase. In the NO assay, carvacrol showed statistically significant efficacy starting at 75 μg/mL, resulting in a 33% reduction. Carvacrol altered bacterial growth phases and increased membrane permeability, leading to higher release of nucleotides and proteins compared to nystatin and amoxicillin. In stability tests, 20% DMSO was the most suitable solvent post-centrifugation. FTIR analysis identified intermolecular interactions between the polymer and carvacrol. Antimicrobial analysis by disk diffusion showed the formation of inhibitory halos, with larger diameters as the carvacrol concentration increased, approaching the positive control at the highest concentration.