Porcelain adherence to high-palladium alloys.

The adherence of porcelain to four representative high-palladium alloys of the first generation (Pd-Cu-Ga) and second generation (Pd-Ga) was measured by use of a gold-palladium alloy as a control. The area fraction of adherent porcelain after metal-ceramic specimens were debonded in biaxial flexure at constant strain was calculated from the characteristic Si x-ray intensity with a standardized scanning electron microscope/energy-dispersive spectroscopy technique (SEM/EDS). The gold-palladium alloy exhibited the highest percentage of cohesive fracture through the porcelain, the two first-generation alloys were intermediate, and the two second-generation alloys exhibited the lowest area fractions. This study demonstrated that conventional visual (naked eye) or microscopic examination of the fractured metal-ceramic specimens at moderate magnification and the use of standard quantitative metallographic techniques were inadequate to provide accurate measurements of the area fraction covered with porcelain.