A crown ("cap") is a tooth-like covering placed over a carefully prepared pre-existing tooth. Crowns serve many functions, such as to strengthen, restore or improve the appearance of your natural tooth. A crown can support the tooth when there is no longer sufficient tooth structure left to place a filling. Crowns may also be used to protect the structure of a tooth that is fractured or broken, and can be attached to bridges or dentures.For individuals who wish to replace missing teeth, dental implant crowns may be an effective long-term solution. Implant crowns provide greater structural support and last longer than either bridges or dentures. Implants serve as the artificial root to which new implant crowns are bonded.