Micro push-out bond strengths of 2 fiber post types luted using different adhesive strategies

Objective. The objective of this study was to evaluate the push-out bond strengths of carbon and glass fiber posts adhesively luted with Panavia F 2.0 and RelyX Unicem luting cements, as well as a modified application procedure using RelyX Unicem cement in combination with a single-bottle total-etch adhesive in 3 segments of teeth. Study design. Sixty single-rooted human maxillary central incisors and canines were sectioned below the cementoenamel junction, and the roots were endodontically treated. The roots were divided into 2 fiber-post groups, and then divided into 3 subgroups of 10 specimens each to test different luting strategies. Bonded specimens were cut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a stereomicroscope at original magnification X40. Results. Micro push-out bond strengths were significantly affected by the type of luting agent and the type of post (P < .05). In all root sections, the push-out bond strength values of glass fiber posts were significantly higher than that of carbon fiber posts (P < .05). Moreover, the highest push-out bond strengths were measured for Panavia F 2.0 and RelyX Unicem cements. These values were significantly higher than that of modified application procedure in the medium section for both glass-and carbon-fiber posts, and in the apical root sections only for glass-fiber post (P < .05). In each region, the modified application procedure showed the lowest bond strength values. Adhesive failure between dentin and cement was the most frequent type of failure. Conclusions. In all root segments, the glass fiber post provided significantly increased post retention compared with the carbon fiber post, regardless of the luting strategy used. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:534-544)