(TC05) Analysis of Microorganisms and Cytokines in Periapical Lesions

Abstract: Microorganisms may be present in periapical lesions (PL) of endodontic origin, which mostly correspond to inflammatory reactions. The aim of this study was to investigate the presence of bacterial species in PL of teeth with endodontic infections using the Checkerboard DNA-DNA hybridization method and to investigate the levels of pro-inflammatory cytokines: IL1-α, IL1-β, IL-6, and TNF-α. Forty-eight PL were collected during endodontic microsurgery. The samples were prepared and submitted to Checkerboard with 40 probes for target species. Samples were also analyzed by the enzyme-linked immunosorbent assay method. The results were analyzed in an Excel table to test the frequency and mean of bacterial species, in addition to the mean and standard deviation of cytokines. Bacteria were detected in 44 PL. The most frequent bacterial species were Enterococcus hirae, Enterococcus faecium, Prevotella nigrescens, Fusobacterium periodonticum, Staphylococcus epidermidis and Leptotrichia buccalis with frequencies of 50%, 58.3%, 58.3%, 60.4%, 68.7%, and 54.2%, respectively. The number of species in the PL ranged from 1 to 40, with an average of 11.4 (±10.9) species. The mean (and standard deviation) of IL1-α, IL1-β, IL-6, and TNF-α levels were respectively 56.12 (76.58); 83.14 (88.01); 17.17 (17.37); and 2.18 (1.96) pg/ml. It was concluded that PL are composed of different bacterial species, both Gram-negative and Gram-positive, and have pro-inflammatory cytokines.