RESUMO
AIM: This study aimed to investigate the association between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia employing polymerase chain reaction (PCR). MATERIALS AND METHODS: Microbial samples were obtained from 60 cases with necrotic pulp with primary teeth infections. DNA extracted from samples were analyzed for endodontic pathogens by using species-specific primers. RESULTS: P. gingivalis/T. denticola were detected in 15 symptomatic teeth associated with periapical lesions. T. forsythia/T. denticola were found in 16 symptomatic teeth associated with pain and swelling. P. gingivalis was detected in 9 teeth which were associated with pain, 2 with tenderness on percussion, and 15 with periapical lesions. Statistically significant associations were found between T. forsythia as well as T. denticola in relation to clinical findings of pain and swelling. (P < 0.05). Red complex bacteria showed no statistical significant association with the presence of signs and symptoms. CONCLUSION: Prevalence of P. gingivalis, T. denticola, and T. forsythia suggested association of these bacteria with symptomatic infected pulp and periradicular diseases.