| The tooth may be restored with a composite filling material if it is a front tooth and the cavity is small, but back teeth in many cases will need a crown. To prepare the tooth for a crown, your dentist first will have to build up a foundation to strengthen the tooth and support the crown. This buildup is called a core. To help hold the core in place, your dentist may have to use a post. To do this, your dentist will remove some of the root filling material in the root canals to make room for the post, which is a metal rod. Posts can be prefabricated and used with a core material that is built up around the post in the tooth. Post and cores can also be cast in one piece. A cast post and core often used in front teeth. It takes two dental visits to complete the process: one to prepare the tooth and create an impression of the post space, and the second to cement the post into tooth. The crown, which is made in a dental laboratory, is composed of porcelain, metal, or a combination of the two. It is cemented onto the foundation. ©2002-2005 Aetna, Inc. All rights reserved. Reviewed by the faculty of Columbia University College of Dental Medicine | 
