title: The shear bond strength of self-adhesive resin cements to dentin and enamel: an in vitro study.
abstract: BACKGROUND
  Clinicians continue to search for ways to simplify bonding procedures without compromising clinical efficacy.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the shear strength of self-adhesive cements RelyX U100 and RelyX U200, and conventional resin cement RelyX ARC to enamel and dentin after different surface treatments.
  
  
  METHODS
  The crowns of 120 bovine incisor teeth were separated from the roots and embedded in epoxy resin in polyvinyl chloride tubes. In each tooth, the area to be cemented was delimited with central holed adhesive tape. The teeth were distributed into 12 groups (n=10) according to the substrate; etched or not with 37% phosphoric acid; and cement type of enamel-U100, enamel-phosphoric acid-U100, enamel-U200, enamel-phosphoric acid-U200, enamel-ARC, enamel-phosphoric acid-ARC, dentin-U100, dentin-phosphoric acid-U100, dentin-U200, dentin-phosphoric acid-U200, dentin-ARC, and dentin-phosphoric acid-ARC. After 7 days of storage in artificial saliva, shear strength tests were performed by using a universal testing machine (0.5 mm/min). The data were analyzed with 3-way ANOVA and the Tukey test (α=.05). Fracture analysis was performed with a light microscope. Two specimens from each group were analyzed with a scanning electron microscope.
  
  
  RESULTS
  In enamel, ARC (9.96 MPa) had higher shear strength (P=.038) than U100 (5.14 MPa); however, after surface etching, U100 (17.81 MPa) and U200 (17.52 MPa) had higher shear strength (P<.001). With dentin, no significant differences were observed (P=.999), except for dentin-ARC (0.34 MPa) (P=.001). Most fractures were of the adhesive type.
  
  
  CONCLUSIONS
  U200 self-adhesive cement had similar bond strength to the ARC in enamel, but the combination with phosphoric acid had the best bond strength. For dentin, self-adhesive resin cements are equally effective alternatives to conventional resin cement.
authors.affiliation: Graduate student, Department of Dentistry, Endodontic and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Raphaela F
authors.initials: RF
authors.lastname: Rodrigues
authors.affiliation: Graduate student, Department of Dentistry, Endodontic and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Carla M
authors.initials: CM
authors.lastname: Ramos
authors.affiliation: Associate Professor, Department of Dentistry, Endodontic and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Paulo A S
authors.initials: PA
authors.lastname: Francisconi
authors.affiliation: Professor, Department of Dentistry, Endodontic and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil. Electronic address: afborges@fob.usp.br.
authors.forename: Ana Flávia S
authors.initials: AF
authors.lastname: Borges
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000268:Adhesiveness; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D055117:Curing Lights, Dental / Q000145:classification; D001840:Dental Bonding / Q000379:methods; D003743:Dental Enamel / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation; D008853:Microscopy / Q000295:instrumentation; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C462240:RelyX ARC; C587242:RelyX U200; D019279:Resin Cements; D012464:Saliva, Artificial; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C030242:phosphoric acid