Post refers to a thin metal rod used in root canal therapy that is inserted into the root of a tooth that has had previous root canal therapy. There are two different types of posts: prefabricated and those that can be cast at the dental laboratory. Its role as the anchor of a dental crown remains the same regardless of its type.
Root canal therapy is used in order to save teeth that have eroded from significant decay and/or infection and the role of the post is near the end of the root canal process. The post can only be applied to teeth that have had root canal therapy due to the death of the nerve in affected teeth. The space that had been occupied by the nerve is replaced with gutta-percha a sterile plastic material. In making the post parts of the gutta-percha are removed although two to three millimeters should be left to seal the end of the root. This space is necessary as it anchors the post within the root of the tooth. The post is then permanently cemented into the affected tooth and is often used to hold a dental crown. The dental crown is usually kept separate from the post. However in some instances a post is deemed unnecessary to support a dental crown and a dental crown is inserted without a post.