Dental crowns such as porcelain-fused-metal crowns are made out of alloys for strength and durability. Dental crowns cannot be made out of pure gold or porcelain because these materials are too soft and malleable to be able to last many years. When making dental crowns, they need to be set in some sort of alloy to make them stand the test of time.
- High noble alloys – Also called precious metals, alloys in this group is composed of over 60% of noble metal (gold, palladium, and platinum). The remaining 40% is gold. These are noted for their low-reactivity and resistance to corrosion and oxidation.
- Noble alloys – Also referred to as semiprecious metal, these alloys have at least 25% noble metal content. They are relatively strong, durable, hard and ductile. It may be yellow or white in color.
- Non-noble alloys – Also called as base metals, it contains less than 25% of noble metal and may even have none at all. They often contain large percentage of nickel, cobalt, chromium or beryllium. These are much harder, stronger and have twice the elasticity of the high-noble and noble metal alloys.