Enterococcus faecalis in dental root canals detected by culture and by polymerase chain reaction analysis

Objective. The objective of this study was to investigate the presence of Enterococcus faecalis in endodontic infections by culture and polymerase chain reaction analyses. Study design. Microbial samples were obtained from 50 teeth with untreated necrotic pulps (primary infection) and from 50 teeth with failing encloclontic treatment (secondary infection). Culture techniques were used including serial dilution, plating, incubation, and biochemical identification. For PCR detection, samples were analyzed using a species-specific primer of the 16S rDNA and the downstream intergenic spacer region. Results. Culture and PCR detected the test species in 23 of 100 and 79 of 100 of the teeth, respectively. E faecalis was cultured from 2 (4%) of 50 necrotic canals and from 21 (42%) of 50 root-treated canals. PCR detection identified the target species in 41 (82%) and 38 (76%) of 50 primary and secondary infections respectively. Conclusion. E faecalis was detected as frequently in teeth with necrotic pulp as in teeth with failing endodontic treatment when a PCR analysis was used.