The effects of peroxide bleaching on composite to enamel bond strength.
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.
Dishman
M V
MV
Department of General Practice, Medical College of Virginia, Virginia Commonwealth University, Richmond.
Covey
D A
DA
Baughan
L W
LW
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
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C062652:Prisma Universal Bond; C074741:Silux Plus; D006861:Hydrogen Peroxide