Effects of dental laboratory processing variables and in vitro testing medium on the porcelain adherence of high-palladium casting alloys.
OBJECTIVE
This study assessed the effects of dental laboratory processing variables and testing medium on porcelain adherence of representative high-palladium alloys.


METHODS
The processing variables were recasting two and three times, porcelain stripping with hydrofluoric acid and rebuilding, and changing the recommended oxidation procedures. The testing medium was air for these four groups and the nontreatment group. In the last group, the specimens were stored and tested in artificial saliva. The metal ceramic specimens were fractured with biaxial flexure in constant strain. The area fraction of adherent porcelain (%) was calculated with a standardized spectrometric technique. A gold-palladium alloy served as the control.


RESULTS
Recasting without adding new alloy negatively affected some high-palladium alloys. Porcelain stripping did not cause a decrease in adherence of the tested alloys. The alternate oxidation treatment reduced significantly the porcelain adherence of the Au-Pd and one Pd-Cu-Ga alloy. Storage and testing in artificial saliva did not significantly affect the porcelain adherence of the alloys. The Au-Pd alloy exhibited the highest porcelain adherence.
Papazoglou
E
E
Section of Restorative Dentistry, Prosthodontics and Endodontics, College of Dentistry, Ohio State University, Columbus 43210-1241, USA.
Brantley
W A
WA
Johnston
W M
WM
Carr
A B
AB
D000268:Adhesiveness; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003735:Dental Casting Technique; D017005:Dental Debonding; D003776:Dental Porcelain; D004356:Drug Storage; D006047:Gold Alloys; D008422:Materials Testing; D016876:Metal Ceramic Alloys; D010084:Oxidation-Reduction; D010165:Palladium; D012464:Saliva, Artificial; D013674:Technology, Dental / Q000379:methods*; D014867:Water
D003722:Dental Alloys; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D012464:Saliva, Artificial; D014867:Water; D003776:Dental Porcelain; D010165:Palladium