A study of various factors influencing shade of bonded porcelain.

Seventy-two specimens of four commercially used precious metals were constructed. The porcelain applied to these specimens was glazed up to nine times for shade comparison. Specimens were also studied with a scanning electron microscope prior to and after application of the porcelain. The important observations from this study were: 1. The four types of precious metals looked alike after casting and surface treatment and prior to application of porcelain. 2. Porcelain-bonded-to-metal shades were not influenced by the types of precious metals used. 3. Porcelain-bonded-to-metal shades remained stable after six glazings and changed only slightly after nine firings.