A dental crown mimics the entire crown of the tooth, with a hollow space inside -- like a cap. In order for the finished crown to fit correctly, the remaining core underneath the crown needs to be reduced to accommodate the crown on top. A crown is designed to securely fit the tooth, keeping bacteria out from underneath the vulnerable tooth structure.
Once the tooth and tissues have become numb, the dentist may decide to place a rubber dam over the teeth involved. The rubber dam is used to trap old filling material, tooth structure, and water from falling into your mouth.Preparing the tooth for a dental crown involves removing very precise amounts of tooth and filling material from the tooth that requires the crown. During this step, the discovery of tooth decay underneath an old filling may occur. If that is the case, all of the decay is removed and a composite core is placed on the tooth. If your tooth has undergone a recent root canal, a composite core may be placed as well during this step.
Once the core is complete, your dentist will continue to shape the tooth, creating a fine margin around the entire core of the tooth, like a shelf, and continue reducing the biting surface of the core until sufficient tooth and filling has been removed.
This step is crucial and generally takes the most time to complete.