title: In vitro evaluation of the bond strength of composite resin foundation materials to dentin.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Assistant Professor, Department of Preventive Dental Sciences, College of Dentistry, University of Dammam, Dammam, Saudi Arabia.
authors.forename: Asim
authors.initials: A
authors.lastname: Al-Ansari
authors.affiliation: Associate Professor, Department of Substitutive Dental Sciences, College of Dentistry, University of Dammam, Dammam, Saudi Arabia.
authors.forename: Fahad
authors.initials: F
authors.lastname: Al-Harbi
authors.affiliation: Professor and Director, Hugh Love Center for Research and Education in Technology, Loma Linda University, Loma Linda, Calif. Electronic address: nbaba@llu.edu.
authors.forename: Nadim Z
authors.initials: NZ
authors.lastname: Baba
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003804:Dentin / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry*
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D019279:Resin Cements