Monitoring of infectious contents, endotoxic and gene presence of resistance to antibiotics of symptomatic and asymptomatic primary infections during endodontic therapy

Abstract

Teeth with pulp necrosis, painful symptomatology and periapical bone destruction tend to be colonized by anaerobic and predominantly Gram-negative microbiota. The main virulence factor of Gram-negative bacteria is represented by the release of endotoxins (LPS) present in the outer membrane of the bacterial cell wall. With the indiscriminate use of antimicrobial agents, these bacteria have developed resistance to them. Thus, the present study aims to: a) to verify the susceptibility of the microbiota of symptomatic and asymptomatic infected root canals to the chemical-mechanical preparation and to the use of intracanal medication for 30 days by counting the colony forming units (CFU); b) to monitor the microbiota composition of symptomatic and asymptomatic infected root canals, and of the periapical abscesses during endodontic therapy, using the checkerboard technique; c) to characterize the cultivable microbiota by Next Generation Sequencing (NGS) in cases of symptomatic and asymptomatic infections, and correlate them with the LPS levels; d) to analyze the effect of the chemical-mechanical preparation and the intracanal medication in the reduction of endotoxin levels of the root canal; e) to monitor the presence of 14 antibiotic resistance genes at different phases of endodontic treatment; f) to correlate these findings with the clinical signs and symptoms presented by the patients. Patients with a need for endodontic intervention due to the pulpal necrosis with the presence or absence of symptomatology will be selected. Monitoring of the stages of endodontic treatment will be done microbiologically through checkerboard and CFUs counting; and trough the quantification of LPS levels and antibiotic resistance genes. The data will be tabulated and statistically analyzed. (AU)