Many people are puzzled when their dentist tells them that their tooth with a crown has a cavity. You may be thinking, "How does that happen? I thought the crown was porcelain or metal, and covers the whole tooth?" Typically crowned teeth develop a cavity on the tooth at the junction where the crown and tooth meet, which dentists call the "margin." The margin is sometimes on the root surface of your tooth, which is more susceptible to getting cavities. This is why oral hygiene is very important in making your crowns last longer. Brushing twice a day and flossing to remove plaque buildup helps to prevent cavities. Some other things that can be done to prevent from getting cavities on crowned teeth are in-office fluoride treatments after your cleanings, a healthy diet, and using a prescription mouth rinse or toothpaste. Please call Essenmacher Family Dental if you have any further questions.