Abstract
BACKGROUND: Root canal treatment (RCT) failure occurs due to persistent infections, missed canals, or anatomical complexities, with Enterococcus faecalis being the predominant microorganism associated with treatment failure. This study aimed to determine the prevalence of E. faecalis in failed root canal cases and its correlation with clinical parameters. MATERIALS AND METHODS: A cross-sectional study was conducted on 50 patients aged 18-50 years requiring nonsurgical endodontic retreatment. Samples were collected using sterile paper points, gutta-percha, and oral swabs. Clinical data such as age, gender, tooth location, and radiographic findings were documented. RESULTS: All samples exhibited polymicrobial infections. E. faecalis was the most prevalent species predominantly isolated using paper points. Other organisms included Streptococcus spp., Candida spp., and Escherichia coli. Oral swabs showed lower detection rates for E. faecalis as compared to other samples for microbial isolation, Gram-positive bacteria (86%) dominated, followed by Gram-negative bacteria (8.3%) and yeast (5%). The findings confirm E. faecalis as the most prevalent microorganism in failed RCT cases. Its resilience, ability to form biofilms, and resistance to conventional treatment contribute to persistent infections. No significant correlation was observed between bacterial prevalence and demographic factors or tooth position. Differences in microbial detection rates among sampling methods emphasize the importance of multiple sampling approaches for accurate microbial recovery. CONCLUSION: E. faecalis is highly prevalent in refractory endodontic infections, underscoring its role in treatment failure. The use of sterile paper points and gutta-percha samples effectively detects intracanal microbes. Advanced molecular techniques may further improve the understanding of endodontic microbiota and help reduce failure rates.