When a tooth is cracked, decayed, or damaged, a dental crown (cap) may need to be fitted onto the tooth. A dental crown is a cemented covering that fits over the original tooth. Crowns can be made of porcelain, acrylic resin, an amalgam or a mix of these materials. Porcelain crowns typically have the most realistic appearance. They maybe less durable than other materials. Dental crowns can whiten, reshape, and realign existing teeth, adding to a healthy and vibrant smile