A dental crown, sometimes referred to as a cap, is used when a tooth has large amount of decay and is at risk of breaking. Once the dentist removes the decay from the tooth, there may not be enough good bone left to support the daily stresses of chewing, clenching or grinding. In order to prevent the tooth from breaking, and requiring removal, a crown is placed on top of the remainder of the natural tooth. Crowns are typically made of metal or porcelain. A crown will fill in the missing tooth structure so that remaining natural tooth is protected from the stresses of eating, clenching or grinding.