Evaluation of the antibacterial activity of calcium hydroxide, chlorhexidine, and N-acetylcysteine against anaerobic bacteria.

• Grant number: 24/01687-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2024
• End date: February 28, 2025
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Amjad Abu Hasna
• Grantee: Júlia Andrade de Oliveira
• 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

In endodontic infections, the character of the bacterial biofilm, adhered to the interfaces of the root canal complex, demonstrates an important and determining role in the progression and persistence of pulpal and periapical changes. Given that, the elimination of microorganisms or reduction of the microbial load defines the treatment prognosis. It is known that the biofilm dispersed in the root complex is polymicrobial, with a predominance of anaerobic bacteria, so that bacterial complexity hinders the immunological response, adding challenges to the success of endodontic treatment. Therefore, the objective of this study will be to evaluate the effectiveness of calcium hydroxide, chlorhexidine and N-acetylcysteine, and their associations, under obligate anaerobic bacteria, in an in vitro study. Five strains of P. micra (ATCC 23195) and P. intermedia (ATCC 33563) will be used, inoculated, standardized, on Brucella agar (Himedia, Mumbai, India) enriched with blood and incubated in an anaerobic chamber. Then, the minimum inhibitory concentration (MIC) will be determined using the broth microdilution method, and the minimum microbicidal concentration (MCC). Furthermore, antibiofilm activity will be evaluated using the MTT test, and biomass evaluation using the crystal violet test. The data will be statistically analyzed, initially through the normality test, aiming at the application of the appropriate statistical test. The significance level adopted will be the conventional value of 5%. With the development of this project, it is expected to comparatively evaluate the action of intracanal medications on anaerobic bacteria present in infected root canals.