title: The effects of peroxide bleaching on composite to enamel bond strength.
abstract: OBJECTIVE
  The objective of this in vitro study was to evaluate the effects of an in-office type of bleaching regimen on the composite to enamel bond.
  
  
  METHODS
  The enamel on forty extracted human teeth was subjected to a 25% hydrogen peroxide bleaching treatment. Ten additional unbleached specimens served as controls (Group A). The 40 bleached specimens were divided into four equal groups (Groups B-E). Composite cylinders were bonded to the prepared surfaces at various time intervals following bleaching. Group B was bonded immediately, Group C at 1 d, Group D at 1 wk, and Group E at 1 mon post-bleaching.
  
  
  RESULTS
  Mean shear bond strength values showed a significant decrease in bond strength for Group B. However, the bond strength returned to normal values after 1 d and remained normal for at least 1 mon. Scanning electron microscope examination showed an apparent decrease in the number of resin tags present in the enamel/composite interface for Group B compared with the other groups including controls.
  
  
  CONCLUSIONS
  Polymerization inhibition of the resin bonding agent is the likely mechanism for the effects of the bleaching on bond strength.
authors.affiliation: Department of General Practice, Medical College of Virginia, Virginia Commonwealth University, Richmond.
authors.forename: M V
authors.initials: MV
authors.lastname: Dishman
authors.forename: D A
authors.initials: DA
authors.lastname: Covey
authors.forename: L W
authors.initials: LW
authors.lastname: Baughan
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D017220:Dentin-Bonding Agents; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013718:Tensile Strength; D014073:Tooth Bleaching
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; C062652:Prisma Universal Bond; C074741:Silux Plus; D006861:Hydrogen Peroxide