Retracted: Push‐out bond strengths of two fiber post types bonded with different dentin bonding agents

Abstract

The aim of this study was to evaluate the regional push-out bond strengths for two fiber-reinforced post types using three different dentin bonding agents. Sixty single-rooted extracted human first premolar teeth were sectioned below the cemento-enamel junction, and the roots were endodontically treated. Following standardized post space preparations, the roots were divided into two fiber-post groups (Glassix and Carbopost), and further divided into three subgroups of 10 specimens each for the bonding systems self-etching dentin bonding agents (Clearfil SE Bond and Optibond all-in-one), and total-etching dentin bonding agent (XP Bond). A dual-cure resin luting cement (Maxcem) was then placed in the post spaces and posts were then seated into the root canals polymerized through the cervical portion. The roots were then cut into 3-mm thick sections. Push-out tests were performed at a crosshead speed of 0.5 mm/min. The data were analyzed with multivariate ANOVA (alpha = 0.05). The morphology of interface between different dentin bonding agents from the cervical sections were analyzed with SEM. Glass fiber-reinforced posts demonstrated significantly higher push-out bond strengths than carbon fiber-reinforced posts (p < 0.001). Bond strength values decreased significantly from the cervical to the apical root canal regions (p < 0.001). Self-etching dentin adhesive Clearfil SE Bond and total-etching dentin adhesive XP Bond demonstrated similar bond strengths values and this was significantly higher compared with the Optibond all-in-one in cervical root canal region. In conclusion, in all root segments, the glass fiber-reinforced posts provided significantly increased post retention than the carbon fiber-reinforced posts, regardless of the adhesive used.

Relining effects on the push-out shear bond strength of glass fiber posts

“…The apical third, in the deepest canal region, showed lower shear bond strength values in groups ARC-NR and U100-R, in agreement with earlier studies 5,24 . Unlike the cervical third, the apical root region is not well visualized and is difficult to reach.…”

“…Shear bond strength in the root thirds tended to decrease with root canal depth (Table 2), corroborating several studies 24,25 . Therefore, the third hypothesis tested in the present study, which was that post shear bond strength would be higher in the cervical than in the other root regions, was accepted.…”

“…This is explained by the deficient dentin hybridization 18,23,24 and incomplete smear layer removal promoted by its weak-acid monomers and hydrolysis of adhesive components 7 . Given these discrepancies, the bonding behavior of cements deserves further studies, especially since the high variability of the root canal environment hinders the application of cementation techniques.…”

“…Compared with the middle and apical thirds, it exhibits higher density of larger-diameter tubules per area 4,5,24 , facilitating the penetration of resin cement 4,5 . With easy visualization and accessibility, procedures such as cleaning, application of adhesive agents and evaporation of materials are efficient 19 .…”

Development of a new direct core build-up method using a hollow fiber-reinforced post

“…Pullout tests 15,16) , push-out tests [17][18][19] , and microtensile tests 20) are typically used to test the adhesion at the interface between the post and the restoration material. Push-out tests and microtensile tests were inadequate to test the adhesion of the hollow post in this study because a severed specimen is required for such tests.…”