A tooth crown is a tooth-shaped “cap” or protective cover that your dentist places over your tooth to restore its shape, size and appearance.2 A crown is cemented onto your tooth and covers the tooth so it can function normally again.2 You may need a crown for several reasons, including:2 Covering misshapen or discolored teeth Restoring a broken tooth Holding a dental bridge in place Protecting a tooth after a root canal Covering a tooth with a large filling Protecting a weak or decaying tooth from breaking Covering a dental implant Crowns can be made from different materials, including metal alloys, porcelain fused to metal, ceramic and resin.2 Dentists usually select a material based on the color of your tooth, the tooth’s location and the cost of the material.2