Isabela N. Rôças

Bio: Isabela N. Rôças is an academic researcher from Estácio S.A.. The author has contributed to research in topics: Root canal & Periodontitis. The author has an hindex of 64, co-authored 197 publications receiving 12852 citations. Previous affiliations of Isabela N. Rôças include Federal University of Rio de Janeiro & Federal University of Rio Grande do Norte.

Polymerase chain reaction–based analysis of microorganisms associated with failed endodontic treatment

Abstract: Objective In this study, we aimed to investigate the occurrence of several microbial species in cases of failed endodontic therapy by means of the polymerase chain reaction (PCR). Study design Root canal samples were taken from 22 root-filled teeth with persistent periradicular lesions selected for re-treatment. DNA was extracted from the samples and analyzed for the presence of 19 microbial taxa by using the polymerase chain reaction. Results All samples were positive for at least 1 of the target microbial species. Enterococcus faecalis was the most prevalent species—detected in 77% of the cases. The other most prevalent species were Pseudoramibacter alactolyticus (52%), Propionibacterium propionicum (52%), Dialister pneumosintes (48%), and Filifactor alocis (48%). Candida albicans was found in 9% of the samples. The mean number of species in samples filled up to 2 mm short of the radiographic apex was 3 (range, 1-5), whereas cases in which the filling was greater than 2 mm from the apex yielded a mean of 5 species (range, 2-11). This difference was statistically significant (P Conclusions Microorganisms occurred in all cases of root-filled teeth associated with periradicular lesions, which lends strong support to the assertion that treatment failures are rather of infectious etiology, caused by persistent or secondary intraradicular infections. E faecalis was the most prevalent species, followed by 4 other anaerobic species: P alactolyticus, P propionicum, D pneumosintes, and F alocis. All examined samples harbored at least 1 of the following gram-positive bacterial species: E faecalis, P alactolyticus, or P propionicum.

Diversity of Endodontic Microbiota Revisited

Abstract: Although fungi, archaea, and viruses contribute to the microbial diversity in endodontic infections, bacteria are the most common micro-organisms occurring in these infections. Datasets from culture and molecular studies, integrated here for the first time, showed that over 460 unique bacterial taxa belonging to 100 genera and 9 phyla have been identified in different types of endodontic infections. The phyla with the highest species richness were Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. Diversity varies significantly according to the type of infection. Overall, more taxa have been disclosed by molecular studies than by culture. Many cultivable and as-yet-uncultivated phylotypes have emerged as candidate pathogens based on detection in several studies and/or high prevalence. Now that a comprehensive inventory of the endodontic microbial taxa has been established, future research should focus on the association with different disease conditions, functional roles in the community, and susceptibility to antimicrobial treatment procedures.