If a tooth is missing large amount of tooth structure due to a previous larger filling or large decay, a crown is required to strengthen and protect the tooth. Also known as a cap, it is a full coverage restoration. This means that it covers, at minimum, the entire biting surface of the tooth. Crown procedures usually take two appointments separated by 2-3 weeks. The tooth is prepared for a crown during first appointment and a temporary crown is placed. The permanent crown is cemented or bonded during second appointment.