title: Tensile bond strength of four resin luting agents bonded to bovine enamel and dentin.
abstract: BACKGROUND
  The resistance to fracture of ceramic restorations depends on adequate bonding to tooth structure. The dental substrate and the types of resin luting agents used are believed to produce variability in adhesive properties.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the tensile bond strength of 4 resin luting agents to bovine enamel and dentin.
  
  
  METHODS
  Forty bovine incisors were embedded in acrylic resin and ground horizontally with water-cooled silicon carbide paper to expose enamel (20 teeth) and dentin at the enamel/dentin junction (20 teeth). Ten standard cone-shaped specimens with a 3-mm diameter base were prepared for each of the following resin cements: Resin Cement, Rely X ARC, Nexus, and Enforce. Five specimens of each material were bonded to enamel and the other 5 to dentin with these resin luting agents and their respective adhesive systems, according to the manufacturers' directions. After 7 days of storage in distilled water at 37 degrees C, specimens were subjected to tensile forces in a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Bond strength data were analyzed with analysis of variance for substrate and material. Means were compared with Tukey's test at the 0.05 level of significance.
  
  
  RESULTS
  Analysis of variance disclosed that both substrate (P<.001) and material (P<.05) demonstrated statistically significant differences, but their interaction was not significant. The bond strengths (MPa) obtained for Resin Cement (11.5 +/- 3.0), Rely X ARC (11.4 +/- 3.1), Nexus (10.0 +/- 1.4), and Enforce (11.8 +/- 2.8) were statistically the same for enamel. For dentin, bond strengths (MPa) for Rely X ARC (9.6 +/- 1.8), Resin Cement (9.3 +/- 0.9), and Enforce (7.8 +/- 2.9) were significantly higher than for Nexus (3.5 +/- 0.8). Significantly higher bond strengths (MPa) were also observed for enamel (11.2 +/- 2.5) than dentin (7.5 +/- 1.6).
  
  
  CONCLUSIONS
  Within the limitations of this study, tensile bond strengths of resin luting agents to enamel were higher than those to dentin, and the bond strength values of Nexus to dentin were significantly lower (P<.05) than the other cements tested.
authors.affiliation: School of Dentistry, Federal University of Pelotas, Brazil.
authors.forename: Cristiane Soares
authors.initials: CS
authors.lastname: Mota
authors.forename: Flávio Fernando
authors.initials: FF
authors.lastname: Demarco
authors.forename: Guilherme Brião
authors.initials: GB
authors.lastname: Camacho
authors.forename: John M
authors.initials: JM
authors.lastname: Powers
mesh_terms: D000268:Adhesiveness; D000704:Analysis of Variance; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D013696:Temperature; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
chemical_list: C103503:EnForce-Sure Cure; C433206:Nexus; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D014867:Water; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate