Prevalence of Enterococcus faecalis and Porphyromonas gingivalis in infected root canals and their susceptibility to endodontic treatment procedures: a molecular study.

INTRODUCTION Because apical periodontitis is recognizably an infectious disease, elimination or reduction of intracanal bacteria is of utmost importance for optimum treatment outcome. OBJECTIVE The prevalence of Enterococcus faecalis and Porphyromonas gingivalis in infected root canals was studied Also, the effect of endodontic therapy by using intracanal medicaments, calcium hydroxide paste (CH) or gutta-percha points containing calcium hydroxide (CH-GP) or chlorhexidine (CHX-GP) on these microorganisms was assessed by polymerase chain reaction (PCR) assay. METHODS Fifty-one patients with chronic apical periodontitis were randomly allocated in one of the fol- lowing groups according to the intracanal medicament used: CH, CH-GP and CHX-GP group. Bacterial samples were taken upon access (S1), after chemomechanical instrumentation (S2) and after 15-day medication (S3). PCR assay was used to detect the presence of selected bacteria. RESULTS E. faecalis was detected in 49% (25/51) and P. gingivalis in 17.6% (9/51) of the samples. Samples which showed no bacterial presence at S1 were excluded from further analysis. Overall analysis of all 29 samples revealed significant differences between S1 and S2 (p < 0.001), S2 and S3 (p < 0.05), and S1 and S3 (p < 0.001). When distinction was made between the intracanal medications, there was a significant difference in the number of PCR positive samples between S1 and 52, S1 and S3, but not between S2 and S3 samples. CONCLUSION E. faecalis is more prevalent than P. gingivalis in primary endodontic infection. Intracanal medication in conduction with instrumentation and irrigation efficiently eliminates E. faecalis and P. gingivalis from infected root canals.