Regional bond strengths of a dual-cure resin core material to translucent quartz fiber post.

Purpose: To evaluate the microtensile bond strength (muTBS) of a dual-cure resin core material to different regions of translucent quartz fiber post in a post cavity using different surface treatments.

Methods: 30 translucent quartz fiber posts (Light-Post) were used and divided into six groups according to the surface treatments: (1) no surface treatment (Control); (2) photo-cure bonding agent, Clearfil Liner Bond 2V Bond A (PLB); (3) dual-cure bonding agent, Clearfil Liner Bond 2V Bond A+B (DLB); (4) BdA+B followed by light-cured for 20 seconds (DLB & LC); (5) silane coupling bonding agent, Clearfil Photobond with Porcelain Bond Activator (PB+PBA); (6) PB+PBA followed by light-cure for 20 seconds (PB+PBA&LC). Treated post were cemented into artificial post cavities using a dual-cure composite core material (Clearfil DC Core) and light-cured for 60 seconds from the top of the cavity. After 24-hour storage in water, each specimen was serially sliced into twelve 0.6 x 0.6 mm-thick beams for the muTBS test. The data were divided into three regions (upper/middle/bottom) and analyzed using two-way ANOVA and Dunnet's T3 multiple comparisons (alpha = 0.05).

Results: The highest bond strength was present in the silane coupling bonding agent group for all regions (P < 0.05). Application of the bonding agent to the post surface significantly improved the bond strength compared with control (P < 0.05). There were no significant differences in muTBS at all regions between the photo and dual-cure type bonding agents (P < 0.05). The bond strength significantly decreased at the bottom region when the post surface was treated with bonding agents (P < 0.05), whereas no regional differences in bond strength were found in the silane coupling bonding agent group (P > 0.05).