Microbiological evaluation of primary endodontic infections in teeth with and without sinus tract

Aim To examine the microbiological status of primary endodontic infections in teeth with and without a sinus tract. Methodology Samples were collected by means of a size 15 H‐type file and two sterile paper points from 30 cases of primary endodontic infections with (n = 15) or without (n = 15) a sinus tract. The presence of 40 bacterial species was determined by the checkerboard DNA‐DNA hybridization method. Results The species found at the highest levels and prevalence were Fusobacterium nucleatum sp. vincentii, Porphyromonas gingivalis, Veillonella parvula, Enterococcus faecalis, Campylobacter gracilis and Neisseria mucosa. Total bacterial counts were similar between teeth with (44 × 10⁵) and without (50 × 10⁵) a sinus tract (t‐test: P > 0.05). E. faecalis, Streptococcus anginosus, Capnocytophaga sputigena and Capnocytophaga gingivalis had significantly higher counts in the absence of sinus tract (Mann–Whitney test, P < 0.05). Higher levels of P. gingivalis and Fusobacterium nucleatum sp. nucleatum were observed in cases with a sinus tract. Leptotrichia buccalis (OR = 1.83; CI 95%) and Porphyromonas endodontalis (OR = 2.15; CI 95%) were associated with an increased chance of subjects having a sinus tract. Conclusions Primary endodontic infections were associated with a large variety of bacterial species. Specific differences between the composition of the microbiota of primary root canal infections were observed in cases with or without a sinus tract.