Abstract:
Endodontic failures are mainly caused by persistence of microorganisms in the root canal system. Enterococcus faecalis has been reported as the most commonly isolated species from root canals with endodontic treatment failure in many studies, but was not the dominant species in others. Recent studies showed that Candida albicans is found together with Enterococcus faecalis within infected root canals in a polymicrobial community and both species can form biofilm. Therefore, this study aims to investigate the prevalence of Enterococcus faecalis and/or Candida albicans in root canals requiring retreatment by using both culture-based and polymerase chain reaction (PCR) techniques, and examine its relationship with clinical parameters and the capacity for biofilm formation. Clinical samples obtained from previously filled root canals that required retreatment were taken from 41 teeth (35 adult patients). Clinical parameters, including presence of signs and symptoms, presence of periapical lesion, size of periapical lesion in radiographs, quality of previous root filling and quality of the coronal restoration, were obtained by clinical and radiographical examination. We determined the prevalence of Enterococcus faecalis and Candida albicans by using both culture-based and PCR. The capacity of biofilm formation of Enterococcus faecalis clinical isolates were tested by crystal violet staining assay and calculated into percentage relative to that of Enterococcus faecalis ATCC29212. Fisher's Exact test analysis was used to assess relationship between the prevalence of Enterococcus faecalis and clinical parameters. The results showed that the prevalence of Enterococcus faecalis was 9.8% and 75.6% by culture and PCR, respectively. Our result did not detect any Candida albicans in the samples. The Clinical parameters examined were not significantly associated with the presence of Enterococcus faecalis (as detected by PCR) in root canals (p>0.05). The clinical isolates of Enterococcus faecalis showed different levels of biofilm formation. However, due to small sample size, we could not make a conclusion or the association between biofilm formation and clinical parameters which should be studies further.
