Effect of a re-wetting agent on the performance of acetone-based dentin adhesives.
OBJECTIVE
To compare the in vitro bond strengths of two acetone-based one-bottle dentin adhesives applied to four surface moisture conditions. The tested hypothesis was that wetting a dried dentin surface with an aqueous HEMA solution would result in bond strengths similar or higher than those obtained by leaving the surface moist as per manufacturers' instructions.


METHODS
Eighty flat dentin bonding sites were polished to 600-grit on middle dentin of the labial surface of bovine incisors mounted in acrylic resin. The specimens were equally and randomly divided between two acetone-based dentin adhesives (One-Step and Prime & Bond 2.1) and four different levels of surface moisture (moist dentin, dentin dried for 1 s, dentin dried for 5 s, and dentin dried for 5 s followed by re-wetting with Aqua-Prep, an aqueous HEMA solution). A composite post was then adapted to the treated area and light-cured. After thermocycling, the bond strengths were determined by testing the specimens in shear. Field Emission SEM examinations were carried out to evaluate the effects of different treatments on the dentin-resin interface.


RESULTS
Statistical analysis revealed that the application of One-Step resulted in similar mean shear bond strengths for the groups in which moisture was present on the dentin surface (12.0-14.2 MPa). The mean shear bond strengths for the group in which One-Step was applied to a dried dentin surface was significantly lower (6.0 MPa). For Prime & Bond 2.1, the application of a re-wetting solution significantly increased mean shear bond strengths (13.9 MPa). The remaining three Prime & Bond 2.1 groups yielded statistically similar mean bond strengths, regardless of the surface condition (6.6-8.1 MPa).
Perdigão
J
J
Dept. of Operative Dentistry, University of North Carolina, Chapel Hill 27599-7450, USA.
Swift
E J
EJ
Heymann
H O
HO
Malek
M A
MA
D000096:Acetone / Q000737:chemistry; D000134:Acid Etching, Dental; D000704:Analysis of Variance; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D003188:Composite Resins; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D007180:Incisor; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011109:Polymethacrylic Acids / Q000737:chemistry; D014906:Wetting Agents / Q000737:chemistry*
C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D011109:Polymethacrylic Acids; C103500:Prime & Bond; D014906:Wetting Agents; D000096:Acetone; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate