Effect of solvent and rewetting time on dentin adhesion.
OBJECTIVE
The purpose of this in vitro study was to determine the influence of solvent and rewetting time on microtensile dentin bond strengths of four dentin adhesives.


METHODS
Sixty human molar specimens were divided into four dentin adhesive treatment groups: (1) a water-based total-etch dentin adhesive, EBS Multi; (2) an ethanol-based total-etch adhesive, Excite; (3) an acetone-based total-etch adhesive, Prime & Bond NT; and (4) an ethanol- and water-based total-etch adhesive, Single Bond. For each dentin adhesive, three specimens were assigned to five dentin moisture conditions. Specimens were tested in the tensile mode.


RESULTS
When adhesives were applied to moist dentin, bond strengths varied from 26.2 MPa for Prime & Bond NT to 29.5 MPa for Single Bond without any statistical differences. When applied to dentin that had been dried for 15 seconds, Prime & Bond NT and Excite resulted in the lowest mean bond strengths, but they were statistically similar to each other (7.9 and 8.3 MPa, respectively). Single Bond resulted in a mean bond strength of 12.7 MPa, which was significantly lower than that of EBS Multi (24.1 MPa). For the latter, all mean bond strengths were statistically similar when some amount of moisture was present on the surface. For the other three adhesives, mean bond strengths returned to the range obtained on moist dentin only when dentin was rewet for 30 seconds.


CONCLUSIONS
Bond strengths upon rewetting depend on the type of solvent in the bonding system, and rewetting time.
Perdigão
J
J
Division of Operative Dentistry, Department of Restorative Sciences, Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, USA. perdi001@umn.edu
Frankenberger
R
R
D000134:Acid Etching, Dental; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D001840:Dental Bonding; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008963:Molar; D010756:Phosphoric Acids / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011897:Random Allocation; D012997:Solvents / Q000737:chemistry; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry; D014906:Wetting Agents
D017220:Dentin-Bonding Agents; C113072:EBS adhesive system; C420130:Excite cement; D008689:Methacrylates; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D012997:Solvents; D014906:Wetting Agents; C115612:single bond; D014867:Water; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate