A post and core crown is a type of dental restorstion 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.
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 adequate 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
Structure
A post and core consists of two parts :
- The post
The post is a small rod, usually metal, that is inserted into the root space of the tooth and protrudes from the root a couple of millimetres. The post is then used to hold the core or a filling in place.
Because the post is inserted into the root canal, a post and core can only be made for a tooth that has had root canal treatment.
The core
The core replaces missing tooth structure in preparation for making a new dental crown. The core is then utilized to hold a dental crown in place.
Why are post and cores needed ?
A great deal of a dental crown stability depends on the amount of tooth structure that extends into its interior. If very little tooth structure occupies this space, the crown will be easily dislodged, especially by forces directed at its side.
Basically, the core is rebuilding the tooth so it is closer to its original dimensions. Hence, the crown’s stability will greatly increase, and therefore its long-term chances for success are maximized.
