title: Transenamel and Transdentinal Penetration of H2O2 in Restored Bovine Teeth.
abstract: OBJECTIVE
  To quantify hydrogen peroxide (H2O2) penetration into restored bovine teeth subjected to whitening treatment.
  
  
  METHODS
  Seventy-five enamel/dentin disks were divided into 5 groups (n = 15): intact disks (G1); cavity preparation only (G2); conventional adhesive system and composite resin (G3); resin-modified glass-ionomer cement (G4); and self-etching adhesive only (G5). After 24 h, the disks were placed into artificial pulp chambers containing an acetate buffer solution, and the first whitening session was performed using a 35% H2O2 (hydrogen peroxide) product. The disks were submitted to 10,000 thermal cycles and then stored for 1 year in deionized water. After this period, a second whitening session was performed. After each whitening procedure, the buffer solutions were analyzed for optical density in a spectrophotometer to assess the amount of H2O2 that had diffused. ANOVA and Tukey's test were used to compare the different groups and a Student's t-test was used to compare the different times (p ≤ 0.05).
  
  
  RESULTS
  Prior to aging, group 2 had the highest penetration of H2O2; the other groups showed similar, lower penetration. After thermocycling and aging, all groups showed a significant increase in H2O2 penetration. The greatest penetration of H2O2 into the pulp chamber was found in groups 2 and 5.
  
  
  CONCLUSIONS
  Aged restorations allowed greater H2O2 permeation through the tooth structure.
authors.forename: André Luiz Fraga
authors.initials: AL
authors.lastname: Briso
authors.forename: Rafael Simões
authors.initials: RS
authors.lastname: Gonçalves
authors.forename: Fernanda Almeida
authors.initials: FA
authors.lastname: de Azevedo
authors.forename: Marjorie de Oliveira
authors.initials: Mde O
authors.lastname: Gallinari
authors.forename: Paulo Henrique
authors.initials: PH
authors.lastname: dos Santos
authors.forename: Ticiane Cestari
authors.initials: TC
authors.lastname: Fagundes
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry; D003737:Dental Cavity Preparation / Q000379:methods; D003743:Dental Enamel / Q000378:metabolism*; D003764:Dental Materials / Q000737:chemistry; D003782:Dental Pulp / Q000378:metabolism; D003793:Dental Restoration, Permanent / Q000379:methods; D003804:Dentin / Q000378:metabolism*; D004058:Diffusion; D005899:Glass Ionomer Cements / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000493:pharmacokinetics*; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D058205:Tooth Bleaching Agents / Q000737:chemistry / Q000493:pharmacokinetics*; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D005899:Glass Ionomer Cements; D010756:Phosphoric Acids; D019279:Resin Cements; D058205:Tooth Bleaching Agents; D014867:Water; D006861:Hydrogen Peroxide; C030242:phosphoric acid