title: Selective Acid Etching Improves the Bond Strength of Universal Adhesive to Sound and Demineralized Enamel of Primary Teeth.
abstract: OBJECTIVE
  To evaluate the influence of enamel condition and etching strategy on bond strength of a universal adhesive in primary teeth.
  
  
  METHODS
  Thirty-six primary molars were randomly assigned to six groups (n = 6) according to the enamel condition (sound [S] and demineralized [DEM]/cariogenic challenge by pH cycling prior to restorative procedures) and adhesive system (Scotchbond Universal Adhesive [SBU]) used in either etch-and-rinse (ER) or selfetching (SE) mode, with Clearfil SE Bond as the self-etching control. The adhesives were applied to flat enamel surfaces and composite cylinders (0.72 mm2) were built up. After 24-h storage in water, specimens were subjected to the microshear test. Bond strength (MPa) data were analyzed using two-way ANOVA and Tukey's post-hoc tests (α = 0.05).
  
  
  RESULTS
  Significant differences were found considering the factors adhesive system (p = 0.003) and enamel condition (p = 0.001). Demineralized enamel negatively affected the bond strength, with μSBS values approximately 50% lower than those obtained for sound enamel. SBU performed better in etch-and-rinse mode, and the bond strength found for SBU applied in self-etching mode was similar to that of CSE.
  
  
  CONCLUSIONS
  Enamel etching with phosphoric acid improves the bond strength of a universal adhesive system to primary enamel. Demineralized primary enamel results in lower bond strength.
authors.forename: Bruna Feltrin
authors.initials: BF
authors.lastname: Antoniazzi
authors.forename: Gabriel Ferreira
authors.initials: GF
authors.lastname: Nicoloso
authors.forename: Tathiane Larissa
authors.initials: TL
authors.lastname: Lenzi
authors.forename: Fabio Zovico Maxnuck
authors.initials: FZ
authors.lastname: Soares
authors.forename: Rachel de Oliveira
authors.initials: Rde O
authors.lastname: Rocha
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure*; D003764:Dental Materials / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008963:Molar / Q000648:ultrastructure; D010756:Phosphoric Acids / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical; D013997:Time Factors; D017001:Tooth Demineralization / Q000473:pathology*; D014094:Tooth, Deciduous / Q000648:ultrastructure*; D014867:Water / Q000737:chemistry
chemical_list: C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D010756:Phosphoric Acids; D019279:Resin Cements; D014867:Water; C041330:Scotchbond; C030242:phosphoric acid