Differences in prevalence of selected bacterial species in primary endodontic infections from two distinct geographic locations.

OBJECTIVE: This study intended to compare the prevalence of 7 putative endodontic pathogens in samples of primary endodontic infections taken from patients of 2 distant geographic locations. STUDY DESIGN: Samples from infected root canals associated with asymptomatic periradicular lesions or from pus aspirated from acute periradicular abscesses were collected from patients in Rio de Janeiro, Brazil, and Seoul, South Korea. South Korean samples were frozen and delivered to Brazil, where all steps in the molecular analysis were performed. DNA was extracted and a species-specific nested polymerase chain reaction assay was used to detect 7 target bacterial species. RESULTS: The most prevalent species detected in Brazilian samples were Porphyromonas endodontalis (79% of the cases) , Treponema denticola (79%), and Dialister pneumosintes (76%). The most prevalent species found in South Korean samples were Fusobacterium nucleatum (38% of the cases) , Tannerella forsythia (26%), and Treponema maltophilum (24%). Overall, P endodontalis, D pneumosintes, Filifactor alocis, T denticola, and T forsythia were significantly more detected in Brazilian samples than in South Korean samples ( P < .05). CONCLUSIONS: Findings indicated that the prevalence of some species in infections of endodontic origin may significantly differ from one geographic location to another.

Polymerase chain reaction identification of microorganisms in previously root-filled teeth in a South Korean population.

A large body of evidence indicates that microorganisms are the primary causative agents of endodontic treatment failures. This study intended to assess the occurrence of nine putative endodontic pathogens in root-filled teeth associated with periradicular lesions in a South Korean population using a culture-independent molecular approach. Fourteen root-filled teeth with persistent periradicular diseases were selected for retreatment. After removal of the root canal filling, the canals were sampled, and a polymerase chain reaction assay using taxon-specific oligonucleotide primers was used for microbial detection. Bacteria were present in all cases, as revealed by amplification using ubiquitous 16S rDNA primers. The most frequently detected taxon was Enterococcus faecalis (64%), followed by Streptococcus spp. (21%) and Tannerella forsythensis (14%). The results of this study using a highly sensitive identification method are concurrent with those from other geographical locations using diverse identification methods in that E. faecalis is the main species found in cases of root-filled teeth associated with periradicular lesions.