Effect of post translucency on bond strength of different resin luting agents to root dentin

Abstract

Translucent fiber posts were developed to conduct light into the root canal more effectively, thereby contributing to the polymerization of dual-polymerized resin luting agents. However, there is no consensus in the literature regarding their effectiveness. The purpose of this study was to evaluate the tensile bond strength of fiber posts with different degrees of translucency to bovine dentin with 3 types of resin luting agents. Ninety bovine roots were endodontically treated and divided into 9 groups (n=10) according to the type of post (translucent, white, and black) and resin luting agent (dual-polymerized self-adhesive; dual-polymerized + etch-and-rinse adhesive system; and autopolymerized + etch-and-rinse adhesive system). Tensile tests were performed on a universal testing machine (0.5 mm/min). To determine tensile stress, the bond area of each specimen was calculated. Data were statistically analyzed with ANOVA, Kruskal-Wallis, and Mann-Whitney tests (α=.05). Mean (standard deviation) tensile bond strength values (5.53 ± 2.29 MPa) were significantly lower for translucent posts than for white (9.51 ± 1.31 MPa) and black posts (10.12 ± 3.44 MPa) with a dual-polymerized luting agent in combination with an adhesive system (P=.012). For white (6.02 ± 1.88 MPa) and black posts (4.14 ± 0.6 MPa), the self-adhesive luting agent led to lower tensile bond strength than the dual-polymerized luting agent in combination with an adhesive system (P=.003). Irrespective of post type, the autopolymerized luting agent provided the lowest tensile bond strength (P<.001). Microscopic analysis revealed that resin luting agents adhered more to the post surface than to the root dentin. Post translucency did not increase the tensile bond strength of dual-polymerized resin luting agents.