Many metals used to make dental crowns can be toxic to some degree. Common examples of toxic dental crown materials are: nickel, beryllium and trace amounts of other metals commonly used in the fabrication of dental crowns. Dr. Bennett's Wyoming dental clinic rarely uses dental crown materials that contain metal. He recommends dental crown material compatibility testing before any dental crown is placed.

Dental crowns are also known as “caps” are used to repair broken and/or heavily restored teeth. Generally, if over one half of the tooth is gone (or replaced with a filling) a dental crown is recommended. Dental crowns generally are of three types: all-metal, porcelain fused to a metal core or all-porcelain.