When a tooth is badly decayed, fractured or root canaled, the tooth becomes weak and hollow. A crown is recommended to stabilize the tooth.

Crowns fully cup over the portion of a tooth that lies at and above the gum line and become the tooth's new outer surface.

Crowns can be made out of porcelain ceramic, metal (a gold or other metal alloy), or a combination of both. Other terms that are used to refer to dental crowns are "dental caps" and "tooth caps."