title: Influence of five home whitening gels and a remineralizing gel on the enamel and dentin ultrastructure and hardness.
abstract: OBJECTIVE
  To investigate the influence of calcium phosphate enhanced home whitening agents on human enamel and dentin surface microhardness and ultramorphology.
  
  
  METHODS
  Five intact molars crowns were used for ultrastructural analysis and five for microhardness test. Each resulting coronal structure was cut in slices. After measuring baseline Knoop Hardness Number (KHN) of the enamel and dentin, the slices were divided into six experimental groups and one control (n= 5). G1= 15% carbamide peroxide (CP); G2= 16% CP; G3= Ca and PO4 (remineralizing agent); G4= 16% CP with Ca and PO4; G5= 7.5% hydrogen peroxide (HP) with Ca and PO4; G6=7.5% HP with Ca. After each daily session of treatment, specimens were stored in distilled water (37 degrees C) until the next session. Products were applied for 2 weeks, according to manufacturers' instructions. Additional KHN weredetermined.
  
  
  RESULTS
  Conventional whitening agents (G1; G2) and the gel with Ca (G6), caused KHN decrease (P< 0.05).The remineralizing and whitening agents with Ca and PO4 (G3; G4; G5) did not change KHN. A change of morphology was observed on enamel and dentin surfaces in G1; G2; G5.
authors.affiliation: Department of Biomaterials, Dental School, University of São Paulo, São Paulo Brazil.
authors.forename: Helena Burlamaqui
authors.initials: HB
authors.lastname: Pinheiro
authors.forename: Paulo Eduardo Capel
authors.initials: PE
authors.lastname: Cardoso
mesh_terms: D002130:Calcium Phosphates / Q000494:pharmacology; D000077463:Carbamide Peroxide; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D003747:Dental Enamel Solubility / Q000187:drug effects; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D003808:Dentin Solubility / Q000187:drug effects; D005782:Gels; D006244:Hardness; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010545:Peroxides / Q000494:pharmacology; D013696:Temperature; D058205:Tooth Bleaching Agents / Q000494:pharmacology*; D014089:Tooth Remineralization / Q000379:methods*; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology; D014867:Water / Q000737:chemistry
chemical_list: D002130:Calcium Phosphates; D005782:Gels; D010545:Peroxides; D058205:Tooth Bleaching Agents; D014867:Water; D000077463:Carbamide Peroxide; D014508:Urea; C020243:calcium phosphate; D006861:Hydrogen Peroxide