title: Comparison of shear bond strength of universal adhesives on etched and nonetched enamel.
abstract: BACKGROUND
  The purpose of this study was to evaluate the effect of surface pretreatment with 37% phosphoric acid on the enamel bond strength of different universal adhesives.
  
  
  METHODS
  One hundred and sixty bovine permanent mandibular incisors freshly extracted were used as a substitute for human teeth. The materials tested in this study included 6 universal adhesives, and 2 self-etch adhesives as control. The teeth were assigned into 2 groups: In the first group, etching was performed using 37% phosphoric acid for 30 seconds. In the second group, no pretreatment agent was applied. After adhesive application, a nanohybrid composite resin was inserted into the enamel surface by packing the material into cylindrical-shaped plastic matrices. After storing, the specimens were placed in a universal testing machine. The normality of the data was calculated using the Kolmogorov-Smirnov test. Analysis of variance (ANOVA) was applied to determine whether significant differences in debond strength values existed among the various groups.
  
  
  RESULTS
  Groups with phosphoric acid pretreatment showed significantly higher shear bond strength values than groups with no enamel pretreatment (p&lt;0.001). No significant variation in shear strength values was detected when comparing the different adhesive systems applied onto enamel after orthophosphoric acid application (p&gt;0.05).
  
  
  CONCLUSIONS
  All adhesives provide similar bond strength values when enamel pretreatment is applied even if compositions are different. Bond strength values are lower than promised by manufacturers.
authors.affiliation: Statistics Section, Department of Brain and Behavioral Sciences, University of Pavia, Pavia - Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Beltrami
authors.affiliation: Dentistry Section, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia - Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Chiesa
authors.affiliation: Dentistry Section, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia - Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Scribante
authors.affiliation: Dentistry Section, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia - Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Allegretti
authors.affiliation: Dentistry Section, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia - Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Poggio
mesh_terms: D000818:Animals; D002417:Cattle; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000737:chemistry*; D045662:Dental Etching; D006801:Humans; D007180:Incisor / Q000737:chemistry*; D010756:Phosphoric Acids / Q000737:chemistry*
chemical_list: D003738:Dental Cements; D010756:Phosphoric Acids; C030242:phosphoric acid