title: Shear bond strength of self-etching adhesive systems with different pH values to bleached and/or CPP-ACP-treated enamel.
abstract: OBJECTIVE
  To compare shear bond strengths of three different self-etching adhesive systems of different pH values to enamel bleached with carbamide peroxide, treated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), or treated with CPP-ACP subsequent to bleaching with carbamide peroxide.
  
  
  METHODS
  Thirty-six human third molars were cut into 4 sections and randomly assigned to 4 groups (n = 36): group I: no treatment; group II: bleaching; group III: CPP-ACP; group IV: bleaching and CPP-ACP. After surface treatments, the samples of each group were further divided into three subgroups (n = 12) based on the adhesive used. The adhesives Clearfil SE Bond (CSE), AdhesE (ADE), and Adper SE Plus (ADP) were applied, and resin composite cylinders with a diameter of 2 mm and a height of 4 mm were bonded to the enamel. Then the specimens were subjected to shear bond strength testing. Two-way ANOVA and a post-hoc Tukey's test were used for statistical analysis (α = 0.05).
  
  
  RESULTS
  There were significant differences between the adhesive systems (p < 0.001) and surface treatments (p < 0.001), but no significant interactions were observed between these variables (p = 0.78). The CSE adhesive system showed the highest bond strength, and the bleaching procedure reduced bond strengths (p = 0.001). Furthermore, there were no significant differences in shear bond strength values between the control and CPP groups. However, the differences between other groups were statistically significant (p < 0.05).
  
  
  CONCLUSIONS
  Bleaching reduced shear bond strength to enamel, but CPP-ACP application did not affect the bond strength to intact and previously bleached enamel. The bond strength of adhesives with different pH values to enamel was material dependent.
authors.affiliation: Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Siavash Savadi
authors.initials: SS
authors.lastname: Oskoee
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Bahari
authors.forename: Soodabeh
authors.initials: S
authors.lastname: Kimyai
authors.forename: Elmira Jafari
authors.initials: EJ
authors.lastname: Navimipour
authors.forename: Maryam
authors.initials: M
authors.lastname: Firouzmandi
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000268:Adhesiveness; D000077463:Carbamide Peroxide; D002327:Cariostatic Agents / Q000737:chemistry*; D002364:Caseins / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000187:drug effects / Q000648:ultrastructure*; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D010545:Peroxides / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013499:Surface Properties; D013997:Time Factors; D058205:Tooth Bleaching Agents / Q000737:chemistry*; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; C489662:AdheSE cement; D002327:Cariostatic Agents; D002364:Caseins; C438313:Clearfil SE Bond; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D010545:Peroxides; D019279:Resin Cements; D058205:Tooth Bleaching Agents; C447032:casein phosphopeptide-amorphous calcium phosphate nanocomplex; D000077463:Carbamide Peroxide; D014508:Urea