Evaluation of the presence of Enterococcus Faecalis in root cementum: A confocal laser scanning microscope analysis

The aim of this study is to address the cause of persistent infection of root cementum by Enterococcus faecalis.

A sample of 60 human single-rooted teeth were divided into three groups. Group I (control group) had no access opening and one-third of the apical root cementum was sealed using varnish. Group II had no preparation of teeth samples. In group III, apical root cementum was exposed to organic acid and roughened using diamond point to mimic apical resorption. After access opening in groups II and III, all teeth samples were sterilized using gamma irradiation (25 kGy). E. faecalis broth was placed in the root canal and apical one-third of the tooth was immersed in the broth for 8 weeks with alternate day refreshment followed by biomechanical preparation, obturation and coronal seal. Apical one-third of all teeth samples were again immersed in the broth for 8 weeks with alternate day refreshment to mimic secondary infection. The samples were observed under a confocal microscope after splitting the teeth into two halves.

E. faecalis penetrated 160 μm deep into the root cementum in group III samples and only showed adhesion in group II samples.

Penetration and survival of E. faecalis deep inside the cementum in extreme conditions could be the reason for persistent infection.