Asim Al-Ansari1, Fahad Al-Harbi2, Nadim Z Baba3. 1. Assistant Professor, Department of Preventive Dental Sciences, College of Dentistry, University of Dammam, Dammam, Saudi Arabia. 2. Associate Professor, Department of Substitutive Dental Sciences, College of Dentistry, University of Dammam, Dammam, Saudi Arabia. 3. Professor and Director, Hugh Love Center for Research and Education in Technology, Loma Linda University, Loma Linda, Calif. Electronic address: nbaba@llu.edu.
Abstract
STATEMENT OF PROBLEM: Achieving adequate bonding of composite resin foundation materials to dentin can be a challenge. Bonding can be affected by the type of bonding material and method used. PURPOSE: The purpose of this in vitro study was to test the bond strengths of selected dual-polymerizing composite resin foundation materials to dentin using light, chemical, or dual-polymerized adhesive systems. MATERIAL AND METHODS: Eighty freshly extracted human third molars were sectioned vertically into mesial and distal halves and embedded in acrylic resin using a copper cylinder. Specimens were divided into 16 groups. Each group received a resin foundation that was bonded to dentin according to each manufacturer's instructions. All tested foundations were dual polymerized except Tetric Ceram, which was light polymerized. BisCore, Build-it, CompCore, CoreRestore, and FluoroCore resin foundation materials were bonded to dentin with the use of the corresponding adhesives in 3 different bonding methods: adhesive was light polymerized; adhesive was chemically polymerized; and adhesive was dual polymerized. Each specimen was seated in a custom shear test device, and a load was applied with the descending rod of the jig from a mechanical testing machine with a perpendicular force to the dentin-adhesive interface. Statistical analysis was performed using 2-way ANOVA and post hoc pairwise comparison with Tukey test when statistically significant differences were found (α=.05). RESULTS: Resin foundation materials bonded to dentin with light-polymerized adhesives produced significantly higher bond strengths than when bonded with chemically or dual-polymerized adhesives. No significant difference was found between the single-component and multiple-components adhesives used with Tetric Ceram and BisCore foundations (P=.083). However, BisCore used with All-Bond 2 adhesive (multiple components) produced significantly lower bond strengths than when used with One-Step (P=.024). Adhesive failure was the most common failure location. Cohesive failures occurred mostly in specimens bonded with light-polymerized adhesives. CONCLUSIONS: The light-polymerized adhesives tested produced significantly higher bond strengths when used without chemical activators. The dual-polymerized core foundations produced better bond strengths to dentin when used with light-polymerized adhesives without chemical activators. In comparing single-component with multiple-component adhesive systems with their respective core resins, no difference was found in bond strengths to dentin.
STATEMENT OF PROBLEM: Achieving adequate bonding of composite resin foundation materials to dentin can be a challenge. Bonding can be affected by the type of bonding material and method used. PURPOSE: The purpose of this in vitro study was to test the bond strengths of selected dual-polymerizing composite resin foundation materials to dentin using light, chemical, or dual-polymerized adhesive systems. MATERIAL AND METHODS: Eighty freshly extracted human third molars were sectioned vertically into mesial and distal halves and embedded in acrylic resin using a copper cylinder. Specimens were divided into 16 groups. Each group received a resin foundation that was bonded to dentin according to each manufacturer's instructions. All tested foundations were dual polymerized except Tetric Ceram, which was light polymerized. BisCore, Build-it, CompCore, CoreRestore, and FluoroCore resin foundation materials were bonded to dentin with the use of the corresponding adhesives in 3 different bonding methods: adhesive was light polymerized; adhesive was chemically polymerized; and adhesive was dual polymerized. Each specimen was seated in a custom shear test device, and a load was applied with the descending rod of the jig from a mechanical testing machine with a perpendicular force to the dentin-adhesive interface. Statistical analysis was performed using 2-way ANOVA and post hoc pairwise comparison with Tukey test when statistically significant differences were found (α=.05). RESULTS: Resin foundation materials bonded to dentin with light-polymerized adhesives produced significantly higher bond strengths than when bonded with chemically or dual-polymerized adhesives. No significant difference was found between the single-component and multiple-components adhesives used with Tetric Ceram and BisCore foundations (P=.083). However, BisCore used with All-Bond 2 adhesive (multiple components) produced significantly lower bond strengths than when used with One-Step (P=.024). Adhesive failure was the most common failure location. Cohesive failures occurred mostly in specimens bonded with light-polymerized adhesives. CONCLUSIONS: The light-polymerized adhesives tested produced significantly higher bond strengths when used without chemical activators. The dual-polymerized core foundations produced better bond strengths to dentin when used with light-polymerized adhesives without chemical activators. In comparing single-component with multiple-component adhesive systems with their respective core resins, no difference was found in bond strengths to dentin.