EVALUATION OF PUSH-OUT BOND STRENGTH BETWEEN DIFFERENT SURFACE TREATED GLASS FIBER POSTS AND COMPOSITE

Push out bond strength of composite to glass fiber post

Abstract

Aim: To evaluate the effect of push-out bond strength between different surface treated glass fiber posts and resin composite.

Materials and Methods: Four Cylindrical Glass fiber post (GFP) of 1.3mm diameter were divided into four groups depending on the surface treatment of glass GFP. Group I– no surface treatment done for GFP, group II - silane coupling agent was applied to GFP, then coated with bonding agent, group III – GFP was etched with 37% phosphoric acid, then treated with silane coupling agent and later coated with bonding agent and group IV - GFP was etched with 5% hydrofluoric acid then treated with silane coupling agent and later coated with bonding agent. The surface treated posts were vertically stabilized in the centre of a matrix. Composite was filled circumferentially and incrementally and photo cured. It was then sectioned perpendicular to the vertical axis yielding ten 1.0mm thick discs per fiber post. Ten specimens per group were obtained. They were subjected to push-out bond strength using universal testing machine. One - way analysis of variance and Tukey’s test were performed to verify statistical differences between groups (P< 0.01).

Results: Superior bond strength was seen in 5% hydrofluoric acid etched group. Etching with 37% phosphoric acid or silane coupling agent alone did not show significant difference. GFP without surface treatment showed least bond strength.

Conclusion: Glass fiber posts should be etched with 5% hydrofluoric acid and treated with silane coupling agent before applying bonding agent for a better bond strength between composite and the GFP.

Keywords: Glass fiber post, push-out bond strength, custom made glass fiber post.