Retention Force of Posts Fabricated by the Direct Core Build-up Technique Using Fiber-reinforced Composite Resin Posts

Abstract

 Purpose: Fiber-reinforced composite posts (FRC posts) with adhesive resin cement systems are used for post-and-core build-up on endodontically treated teeth. The objective of this study was to compare the retention force of posts built up by the direct technique and bonded with different adhesive systems.
 Methods: Post spaces 3 mm in diameter and 4 mm in depth were drilled on endodontically treated bovine roots. FRC posts were built up and then luted with three adhesive systems: a self-adhesive resin cement, a conventional composite-type adhesive resin cement with self-etching primer, and a normal bonding system combined with resin composite. The samples were stored in water for 1 or 14 days. Retention force was measured using the pull-out method with a universal testing machine. The maximum load was recorded as the retention force of the post.
 Results: No significant differences in retention force among adhesive systems were found in the 1-day samples. Conventional composite-type resin cement showed the largest retention force in the 14-day samples. In terms of failure mode, cohesive failure of resin cement was the most common.
 Conclusion: This study investigated the retention force of directly-built FRC posts bonded with adhesive resin cements. There were no significant differences among the adhesive systems in the 1-day samples. Although the retention force of the FRC post built-up with self-adhesive resin cement after 14 days storage was smaller than that of conventional composite-type resin cement, this value was similar to that of the normal bonding system.