Identification of Fusobacterium nucleatum in primary and secondary endodontic infections and its association with clinical features by using two different methods.

OBJECTIVE: Fusobacterium nucleatum is an important oral pathogen involved in endodontic infections. This study aimed to assess the frequency of Fusobacterium nucleatum in primary and secondary endodontic infections and its associations with the clinical features in a Brazilian population by using both culture and nested PCR methods. METHODS: A total of 100 microbial samples from patients with primary (n=50) and secondary endodontic infections (n=50) were analyzed by using culture and nested PCR methods. Strict anaerobic techniques were used for culture and identification of F. nucleatum. The DNA extracted from the samples was analyzed for the presence of target species by using species-specific primers. RESULTS: Culture and nested PCR methods detected F. nucleatum, respectively, in 11/100 and 82/100 root canals. F. nucleatum was isolated by culture from 10/50 (20%) root canals with primary infections and from 1/50 (2%) root canal with secondary/persistent infections. Nested PCR detected F. nucleatum in 42/50 (84%) root canals with primary infections and in 40/50 (80%) root canals with secondary/persistent endodontic infections. F. nucleatum was associated with spontaneous pain, tenderness to percussion, pain on palpation, swelling, tooth mobility, wet root canals, hemorrhagic exudate, tooth decay, inadequate restoration, and poor endodontic filling. CONCLUSION: F. nucleatum was found in more cases of primary endodontic infections than in cases of secondary/persistent ones. A higher prevalence of F. nucleatum was detected by using the nested PCR method than by using culture. The presence of F. nucleatum in the root canals was associated with several clinical features. CLINICAL RELEVANCE: The high prevalence of F. nucleatum in the root canals detected by molecular methods, and its association with several clinical features reveals the importance of these species in the development of apical pathologies and reinforces the need of an endodontic treatment directed to bacterial elimination.

Investigation of Filifactor alocis in primary and in secondary endodontic infections: A molecular study.

OBJECTIVE: Identification of specific bacteria in root canals (RCs) in distinct clinical conditions can support the comprehension of pathological processes. Thus, the objective of this clinical study was to investigate the presence of F. alocis in RCs of teeth with primary endodontic infection (PEI) and with persistent/secondary endodontic infection (SEI) by using molecular techniques. It was also aimed to associate its presence with the clinical features. In addition, the levels of F. alocis as well as the total bacterial cells in the samples were also quantitated. DESIGN: One hundred teeth (50 PEI and 50 SEI) were included. Microbial samples were performed using sterile paper points and assessed by using nested PCR and quantitative Real Time PCR (qPCR). The prevalence of F.alocis in RCs from PEI and SEI were compared by chi-square analysis. Fisher´s exact test or Pearson Chi-square, when appropriate, was used to test associations between clinical and radiographic features and the presence of F. alocis. Significance level was set at 5%. RESULTS: F. alocis was detected in 23 and 28 (PEI) and 12 and 11 (SEI) RCs using Nested PCR and qPCR, respectively. Statistically significant associations were found between the presence of F. alocis and PEI, pain, wet canals, swelling, abscess and purulent exudate (P < 0.05). Total bacterial count was similar in both conditions (P > 0.05). CONCLUSIONS: PEI harbour a significantly higher number of F. alocis than those with SEI. Filifactor alocis was significantly associated with clinical features in primary endodontic infections. Total bacterial count was similar in both clinical conditions.