Periodontal Phathogens in Persistent Periapical Lesions

Objectives: Periodontal pathogenic bacteria are implicated in severe forms of periodontal diseases and exist in root canal infections. The purpose of this study was to assess the occurrence of the red complex bacteria in persistent periapical lesions. Materials and Methods: Samples were obtained from 24 patients with persistant periapical lesions who were referred for surgical endodontic treatment. Samples were taken using sterile paper point inserted into the periapical lesion for 10 seconds. The point was stored in special sterile transfer tubes and analyzed with checkboard DNA-DNA hybridization. Results: At least one periodontal pathogenic bacteria was found in 7 of 24 cases. Bacterial species present were T. denticola (3 cases), P. gingivalis (3 cases), B. forsythus (4 cases), P. intermedia (one case), and A. actinomycetemcomitans (3 cases). No particular signs or symptoms was associated with the presence of these bacterial species. Conclusions: Periodontal pathogenic bacterial species are recognized in persistant periapical lesions. This suggests that they may play a role in the pathogenesis of periapical and periradicular diseases and bone resorption.