title: The influence of acidogenic challenge on enamel microhardness around restorations.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the influence of acidogenic challenge on microhardness of enamel adjacent to adhesive restorations in primary and permanent teeth.
  
  
  METHODS
  Occlusal cavities were prepared and immediately restored with two adhesive systems and a composite resin. The specimens were divided into eight groups, according to the type of tooth (primary or permanent), adhesive system (etch-and-rinse or self-etching), and treatment (control or acidogenic challenge). The cariogenic challenge groups were submitted to pH cycling for 10 days. The teeth were prepared for a cross-section microhardness test. Analysis of variance and Tukey's post hoc test were used to analyze the data (α=5 percent).
  
  
  RESULTS
  The adhesive systems did not influence the enamel microhardness (P<.27). Primary teeth were more susceptible to acidogenic challenge (P=.004). The microhardness values for control groups were statistically similar at different indentation depths (P>.05); however, in the acidogenic challenge groups, lower microhardness values were observed in superficial measurements (P<.05).
  
  
  CONCLUSIONS
  Acidogenic challenge negatively influenced the microhardness of the enamel surface adjacent to adhesive restorations. Mineral loss was higher in primary teeth and on the enamel surface.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil. animontag@gmail.com.
authors.forename: Anelise Fernandes
authors.initials: AF
authors.lastname: Montagner
authors.affiliation: Department of Dental Clinic, School of Dentistry, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: Caroline Vargas
authors.initials: CV
authors.lastname: Bittencourt
authors.affiliation: Department of Restorative Dentistry, the School of Dentistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Fabio Zovico M
authors.initials: FZ
authors.lastname: Soares
authors.affiliation: Department of Stomatology, the School of Dentistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Rachel Oliveira
authors.initials: RO
authors.lastname: Rocha
mesh_terms: D019342:Acetic Acid; D003188:Composite Resins / Q000494:pharmacology*; D003731:Dental Caries / Q000628:therapy*; D003738:Dental Cements / Q000494:pharmacology*; D003743:Dental Enamel / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D006244:Hardness; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D011897:Random Allocation; D019279:Resin Cements / Q000494:pharmacology*; D013499:Surface Properties; D017001:Tooth Demineralization; D014094:Tooth, Deciduous
chemical_list: C554641:Adper single bond 2; C438313:Clearfil SE Bond; D003188:Composite Resins; D003738:Dental Cements; C444701:Filtek Z250; D019279:Resin Cements; D019342:Acetic Acid