Porcelain alloys are used to fabricate copings and other substructures for crowns and bridges. These metals are cast to create a strong and properly fitting base to support an esthetic porcelain fused to metal (PFM) crown or bridge. A wide range of high noble, noble and base metal compositions can be used for fabricating PFM substructures, so there are numerous alloys that can be used. When considering a porcelain alloy it is important to consider how well the alloy bonds with your prefered ceramic system. Other key attributes of these materials are their specific working properties for casting, along with color and esthetic qualities.