Permanent crowns can be either all metal, porcelain-fused-to-metal, all resin, all ceramic or all porcelain. Metals used in crowns include gold alloy, other alloys (for example, palladium) or a base-metal alloy (for example, nickel or chromium). Compared with other crown types, less tooth structure needs to be removed with metal crowns, and tooth wear to opposing teeth is kept to a minimum….