A comparison of methods for detecting bacteria in root canal exudate

This study compared the ability of bacterial detection from intracanal exudate by two different methods. One is a conventional method (i.e. the samples were transported into anaerobic chambers immediately after sampling and then moved to an outside laboratory for identification of bacteria). Another is a preculture method (i.e. the samples were inoculated into semisolid medium immediately after sampling, incubated for 24 h under anaerobic conditions, and then moved to the laboratory for bacterial identification). In 22 cases, the preculture method detected bacteria in 18 of 22 cases, whereas the conventional method detected bacteria in 6 of 22 cases. The preculture method showed significantly higher frequency of bacterial detection (p = 0.0003). Gram-positive cocci (alpha-Streptococcus, Enterococcus, etc.) were detected in many cases. These results suggested that the preculture method could be helpful in detecting root canal bacteria and enhance antibiotic treatment of endodontic disease.