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
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.