الفهرس 
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Abstract
The aim of this study was to compare and evaluate the push-out bond strength of a bioceramic sealer (Endosequence BC sealer) and a mineral trioxide aggregate based sealer (MTA Fillapex).
Thirty extracted upper central incisor human teeth were used in this study. The teeth were instrumented using Endosequence NiTi rotary files. The specimens were then obturated using single cone technique and divided into three groups according to the sealer used. Group 1; Endosequence Bc sealer, group 2; MTA Fillapex and group 3; positive control group (zinc oxide eugenol-based sealer; Endofill). Each root was embedded in an acrylic resin in a custom-made copper mold. After setting of the acrylic resin, two transverse sections were cut from the root, a coronal and middle section each two millimeter thick using a water-cooled diamond disc.
Each group was further divided into two subgroups, subgroup a; representing the coronal sections and subgroup b; representing the middle sections. The specimens were then subjected to pushout test. Loading was done by a cylindrical 0.7 diameter plunger and compressive force was applied at a cross-head speed of 1mm/min. specimens were then examined under the stereomicroscope at magnification X5-6 to detect the mode of bond failure.
The results showed that the Endosequence BC sealer and the MTA Fillapex both showed higher pushout strength values than the Endofill sealer. Furthermore, the BC sealer showed significantly higher values than the MTA fillapex. In all group middle sections showed higher values than the coronal ones. Regarding the mode of bond failure, both BC sealer and MTA Fillapex showed mainly cohesive failure.