title: Hardness and microshear bond strength to enamel and dentin of permanent teeth with hypocalcified amelogenesis imperfecta.
abstract: BACKGROUND
  Adhesive procedures are often required to restore teeth affected by hypocalcified amelogenesis imperfecta (HAI).
  
  
  OBJECTIVE
  To evaluate the hardness of enamel/dentin of teeth affected by HAI and the bond strength to these substrates, as well the influence of 5% NaOCl on bond strength.
  
  
  METHODS
  Permanent molars presenting HAI and sound third molars were used. Enamel surfaces were wet-flattened and Knoop hardness was assessed. The two-step, etch-and-rinse adhesive Single Bond 2 (3M ESPE) was applied and resin cylinders bonded to the surfaces and submitted to microshear testing. The subjacent medium dentin was then exposed by wet-grinding. Hardness readings and microshear testing were carried out again. The relationship between hardness and bond strength was assessed by nonlinear regression analysis.
  
  
  RESULTS
  Hardness of normal enamel was higher than hardness of enamel affected by HAI, whereas dentin hardness did not differ from normal to HAI-affected teeth. Enamel and dentin hardness were similar for teeth affected by HAI. Higher bond strengths were obtained to the normal tooth tissues. Dentin bond strength was higher than enamel bond strength. NaOCl exposure did not influence bond strengths. A positive linear relationship between enamel hardness and bond strength was observed.
  
  
  CONCLUSIONS
  HAI imposes challenges to bonding to enamel and dentin.
authors.affiliation: Department of Dentistry, Federal University of Sergipe, Aracaju, SE, Brazil. faria_silva@ufs.br
authors.forename: André Luis
authors.initials: AL
authors.lastname: Faria-e-Silva
authors.forename: Rafael Ratto
authors.initials: RR
authors.lastname: De Moraes
authors.forename: Murilo De Sousa
authors.initials: Mde S
authors.lastname: Menezes
authors.forename: Rodrigo Rodrigues
authors.initials: RR
authors.lastname: Capanema
authors.forename: Altair Soares
authors.initials: AS
authors.lastname: De Moura
authors.forename: Hercílio
authors.initials: H
authors.lastname: Martelli
mesh_terms: D000567:Amelogenesis Imperfecta / Q000473:pathology*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000648:ultrastructure*; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D005260:Female; D006244:Hardness; D006801:Humans; D008297:Male; D033081:Shear Strength; D012973:Sodium Hypochlorite / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D012997:Solvents; C533204:filtek Z350; D012973:Sodium Hypochlorite