Identification of oral spirochetes at the species level and their association with other bacteria in endodontic infections

Objectives. Recent molecular approaches have revealed that fastidious organ isms such as Bacteroides forsythus and oral treponemes were frequently foun d in root canals with apical periodontitis. The purpose of this study was t o identify the isolates of oral spirochetes at the species level in endodon tic infections and to determine their association with B forsythus and Porp hyromonas gingivalis. Study design. Seventy-nine teeth with apical periodontitis were selected fo r this study. After sampling from the root canals aseptically, polymerase c hain reaction amplification for the 16S rRNA gene was performed with eubact erial universal primers. Subsequently, dot-blot hybridization was performed with 8 species-specific oligonucleotide probes. The microbial associations were analyzed by using the odds ratio. Results. The most frequently found species was P gingivalis (27.4%), follow ed by Treponema maltophilum (26%), B forsythus (16.4%), and Treponema socra nskii (2.7%). Other treponemes, including Treponema denticola, were not det ected in our samples. Significant microbial associations were identified be tween T maltophilum, B forsythus, and P gingivalis by performing analysis w ith the odds ratio. Conclusion. Our results indicate that T maltophilum should be included in e tiologic studies of endodontic diseases.