The shear bond strength of acetone and ethanol-based bonding agents to bleached teeth.
OBJECTIVE
The purpose of this in vitro study was to evaluate the: (1) shear bond strength (SBS) of acetone and ethanol-based bonding agents to composite resin 24 hours after being bleached with 35% hydrogen peroxide; and (2) interface morphology and mode of fracture (IMMF) between composite resin and enamel.


METHODS
Forty extracted teeth were randomly assigned into 4 groups: (1) group 1: 35% H2O2 + acetone; (2) group 2: H2O2 + ethanol; (3) group 3: acetone; (4) group 4: ethanol. All teeth were acid etched, bonding agents were applied, and a composite resin stub was bonded and stored again in saline for 24 hours. SBS was determined, and scanning electron microscopy (SEM) was used for IMMF evaluation.


RESULTS
SBS was significantly lower in bleached than unbleached teeth (P < .001), but SBS did not differ between the acetone-based or ethanol-based adhesives (P = .55) and bleaching did not interact with adhesive treatment (P = .39). IMMF analysis of the unbleached teeth showed a continuous interface between the resin and enamel. By contrast, bleached teeth showed sparse contact between the resin and enamel and the resin was poorly infiltrated into the enamel surface.


CONCLUSIONS
Morphologic changes in human tooth enamel, 24 hours after bleaching, were associated with a reduction in the shear bond strength of adhesives.
Montalvan
Ericka
E
Department of Pediatric Dentistry, University of Medicine and Dentistry of New Jersey, Newark, USA.
Vaidyanathan
Tritala K
TK
Shey
Zia
Z
Janal
Malvin N
MN
Caceda
Jorge H
JH
D000096:Acetone / Q000737:chemistry*; D000134:Acid Etching, Dental; D000268:Adhesiveness; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure; D003764:Dental Materials / Q000737:chemistry*; D003804:Dentin / Q000648:ultrastructure; D000431:Ethanol / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D016877:Oxidants / Q000737:chemistry; D033081:Shear Strength; D012997:Solvents / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D014073:Tooth Bleaching
C115611:BOND-1 adhesive; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D016877:Oxidants; D012997:Solvents; C113300:TPH hybrid; D000096:Acetone; D000431:Ethanol; D006861:Hydrogen Peroxide