A: If your doctor has recommended a crown to you, it is likely either to correct a broken tooth or to repair a tooth that has deteriorated due to cavities (decay). The decay in your tooth eats away at healthy tooth structure much like rust eats away at metal. If not removed, decay will deteriorate the tooth to the point where extraction is the only viable treatment option. Sometimes, decay is removed leaving healthy tooth structure, but not much of it. A crown can then be placed, restoring the look and function of your tooth while allowing you to keep your natural, underlying tooth structure. Most crowns are precision-milled porcelain or full metal (gold or silver) and are individually customized for each application in each patient, giving you a natural, long lasting smile.