Effects of temperature on color stability of porcelain stains.

The effects of oven firing on the color stability of extrinsic stains used for characterization and color modification of metal ceramic restorations were studied by comparing the color of the stain as initially applied with that observed after it was fired to the fusion temperature. Perceptible changes were noted for all stains studied. Multiple firings of the stain showed only minor effects on the observed color. The effects at fusion temperatures of 1700 degrees F and 1775 degrees F appeared similar. Finally, there appeared to be no marked differences between the color change observed with the use of autoglazing and overglazing techniques.