The bond strength of an adhesive resin luting cement to a variety of surface treatments of a high-palladium copper alloy.
OBJECTIVE
This study evaluated the tensile bond strength of a bisphenol glycidyl methacrylate (Bis-GMA) resin luting cement with four different surface treatments of a high Pd-Cu alloy.


METHODS
For each surface treatment type (tin-plated, porcelain furnace oxide, air-abraded, and finished-only), 15 opposing half-dumbbell-shaped samples were cast and prepared in new Pd-Cu alloy. Samples were luted with a Bis-GMA resin luting cement at a film thickness of 80 microns using a custom alignment apparatus. Samples were stored in distilled water at 37 degrees C for 24 hours, thermocycled for 1,000 cycles, and then stored for 30 days in distilled water at 37 degrees C. Samples were then subjected to fracture in tension at a loading rate of 0.5 cm/min with the bond strengths calculated in megapascals (MPa). The fractured surfaces were examined using stereomicroscopy and scanning electron microscopy at various magnifications ranging from 5.5x to 500x to determine the type of bond failure (adhesive, cohesive, or mixed).


RESULTS
Tensile bond strengths (mean +/- SD MPa) were: tin-plated, 30 +/- 15.7; porcelain furnace oxide, 23 +/-n 8.6; air-abraded, 8 +/- 8.1; and finished-only, 4 +/- 4.5. Statistical analysis of the tensile bond values using an ANCOVA and Tukey's multiple comparison test at a significance level of 0.05 indicated that there was no difference between the tin-plated and the furnace oxide groups, as well as between the air-abraded and the furnace oxide groups. However, there was significant difference between the tin-plated, the air-abraded, and the finished-only groups. The observed bond failures were predominantly mixed and cohesive in nature with only one adhesive failure.


CONCLUSIONS
There was no significant difference in the tensile bond strengths between the tin-plated group or the porcelain furnace oxide surface group. This suggests that the less-technique-sensitive porcelain furnace oxide surface treatment offers an alternative for achieving high metal-resin bonds to a high Pd-Cu alloy.
Lynde
T A
TA
Department of Prosthodontics, Virginia Commonwealth University, Medical College of Virginia, School of Dentistry, Richmond 23298-0566, USA.
Whitehill
J M
JM
Coffey
J P
JP
Meiers
J C
JC
D000537:Aluminum Oxide; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D003300:Copper / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods; D004595:Electroplating; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010087:Oxides; D010165:Palladium / Q000737:chemistry*; D019279:Resin Cements; D013499:Surface Properties; D013718:Tensile Strength; D014001:Tin
D003722:Dental Alloys; D010087:Oxides; D019279:Resin Cements; D017438:Bisphenol A-Glycidyl Methacrylate; D010165:Palladium; D014001:Tin; D003300:Copper; D000537:Aluminum Oxide