Post and core
Post and core
A post and core crown is a type of dental restoration required where there is an inadequate amount of sound tooth tissue remaining to retain a conventional crown. A post is cemented into a prepared root canal, which retains a core restoration, which retains the final crown.
The role of the post is firstly to retain a core restoration and crown, and secondly to redistribute stresses down onto the root, thereby reducing the risk of coronal fracture. The post does not play any role in reinforcing or supporting the tooth and can in fact make it more likely to fracture at the root.
When deciding whether or not a tooth requires a post and core crown rather than a conventional crown, the following must be established-
- Presence of an adequate coronal tooth structure
- Sufficient length of canal to retain a post
- Curvature and overall anatomy of root canal system
- Sufficient root (radicular) dentine thickness for post preparation
- Restorability of tooth
Types-
Prefabricated post
Prefabricated post and cores take less time to place, as they do not involve any lab work and can be inserted immediately upon the decision to utilize them, once the endodontic therapy has been completed and the post space cleared of gutta percha. After the prefabricated post is properly cemented into the post space, a core material, such as dental composite, can be packed around the cemented post. After the material has been cured or has had a chance to set and properly formed into a crown preparation, an impression can be taken for the fabrication of a prosthetic crown.
Cast post
In cases where the post space is not a good match for a prefabricated post, a cast post and core can be custom fabricated for the tooth.