ABSTRACT
Background: Sealers are universally used along with gutta-percha to obturate the root canals in three dimensions. Push-out bond strength is considered appropriate to measure the adhesion capacity of sealers. Aim: To compare the bond strength of recently introduced bioceramic sealer with commonly used sealers and to evaluate the effect of plunger: base orifice size ratio on push-out bond strength. Methods:One hundred mandibular premolars with single canals were decoronated and instrumented up to master apical file F3 Protaper. Specimens were randomly divided into four groups (n=25) based on the sealer used: Group 1-EndoSequence BC Sealer, Group 2-MTA FillApex sealer, Group3-Apexit Plus sealer & Group 4-AH Plus sealer and obturated using cold lateral compaction technique. After two weeks, 1±0.1mm thick slice of each radicular third of specimens was subjected to push-out testing with modified and standardised plunger: base orifice size ratio for each slice and bond strength calculated. Subsequently the slices were observed under stereomicroscope for failure mode analysis. Results: Results showed that AH Plus sealer had the highest overall bond strength followed by EndoSequence BC sealer and MTA FillApex while as Apexit Plus had lowest bond strength. Bond strength of all sealers reduced from coronal to apical direction except in EndoSequence BC sealer which showed better strength in critical apical third. Higher bond strength values were obtained due to modified relation of plunger with base orifice size. Conclusion: Bond strength of all sealers tested except EndoSequence BC reduces in apical direction and is impacted by plunger: base orifice size ratio.