Effect of Enterococcus faecalis on Pushout Bond Strength of Resin Based Sealer (An In-Vitro Study)

Introduction: When Enterococcus faecalis is present in sufficient amounts, resin sealer can be degraded by esterase-like activity. E. faecalis has potential ability to penetrate the methacrylate-tooth interface, enter the root canal, causing secondary infections. Adhesion of the sealer to dentin and gutta percha was measured by push out bond strength using universal testing machine and adaptation using scanning electron microscope. Aim: This study aims to determine the effect of E. faecalis on push out bond strength of AH Plus epoxy resin-based sealer. Material and methods: A total of 40 recently extracted teeth were used in this experiment. After chemo-mechanical preparation of all samples, they were randomly classified into four groups (n=10): Group 1: Root canals inoculated with E. faecalis. Group 2: Root canals with no bacterial inoculation. Group 3: Root canals inoculated with dead bacteria. Group 4: Root canals inoculated with media only. Obturation was performed by single cone obturation technique. Methods of evaluation: The bond strength of the samples of all groups was calculated by dividing the load by bonding area of the filling area. The load was converted to MPa. Results: Control group 2 “no bacteria” and group 4 “media only” showed the highest statistically significant values of push out bond strength both at apical and coronal sections with no statistically significant difference between them. This was followed by group 3 “dead bacteria” then group 1 “with bacteria” which showed the least values of POBS with statistically significant difference between them and with other groups. Conclusion: E. faecalis demonstrated biodegradation of resinbased sealers. AH Plus sealers cannot eradicate E. faecalis completely.