A post and core is a way of rebuilding a tooth that has lost most of its natural crown, so that it has enough structure to hold a new crown on top. It is most often needed after a root canal on a tooth that was heavily broken down by decay or fracture. A small post is cemented into one of the cleaned root canals to anchor a filling material called the core, which is then shaped to support the crown. The important point is that a post does not strengthen the tooth. It exists only to retain the core when there is too little tooth left for the core to hold on by itself.
Key takeaways
- A post and core rebuilds a tooth that has lost most of its crown, usually after a root canal.
- The post anchors the core; it does not make the root stronger.
- Not every root-treated tooth needs a post, only those with little tooth structure left.
- Fibre posts are now often preferred over cast metal posts because they are gentler on the root.
- Keeping a rim of natural tooth, called a ferrule, improves how long the final crown lasts.
When a post and core is needed
After a root canal, the amount of remaining tooth decides how the tooth is rebuilt. If there is still a good wall of natural tooth, the dentist can simply place a core filling and a crown, with no post required. If decay or a fracture has removed most of the crown, there is not enough for a core to grip, so a post is placed into a canal to anchor it. Front teeth with a single straight canal and back teeth with wider canals are both candidates, and the dentist chooses which canal gives the best support.
Fibre posts versus metal posts
| Type | Material | Main advantage | Main drawback |
|---|---|---|---|
| Fibre post | Glass or carbon fibre in resin | Flexes like dentine, gentler on the root, tooth-coloured | May be less retentive in very short roots |
| Cast metal post | Custom-cast metal | Very strong and retentive | Stiffer, so more force can transfer to the root if it fails |
Many dentists now favour fibre posts for suitable teeth because they behave more like natural dentine, which can mean that if the tooth is ever overloaded it is more likely to fail in a repairable way rather than splitting the root. The choice still depends on the individual tooth, and a dentist will explain which suits yours.
Why the ferrule matters
One of the biggest factors in how long a rebuilt tooth lasts is the ferrule, a band of healthy tooth at least a couple of millimetres tall that the crown grips around, like the way a metal band grips the top of a pencil rubber. When a ferrule is present, the crown holds the tooth together and takes stress off the post. When almost no tooth is left above the gum, the ferrule is lost and the long-term outlook is poorer, which sometimes shifts the decision towards removing the tooth and considering an implant or bridge instead.
What to expect and how long it lasts
Placing a post and core is usually painless because the tooth has already had its nerve removed. The dentist prepares space in a canal, cements the post, builds the core, then takes an impression or scan for the crown. A well-restored tooth with a good ferrule can last many years. The main risks over time are the post loosening or, less commonly, a root fracture, which is why preserving natural tooth and avoiding heavy grinding both help. Regular check-ups let a dentist spot any early movement before it becomes a problem.
Frequently asked questions
Does a post make my tooth stronger?
No. This is a common misunderstanding. A post only anchors the core build-up. The strength comes from the remaining natural tooth and the crown.
Does every root canal tooth need a post?
No. Only teeth that have lost most of their crown need one. Teeth with plenty of structure left are restored with a core and crown alone.
Is a fibre post better than a metal one?
For many teeth fibre posts are preferred because they flex like natural tooth. Metal posts are still used where extra retention is needed. The best choice depends on the tooth.
Is the procedure painful?
Usually not, since the tooth no longer has a live nerve. Local anaesthetic can still be used for comfort around the gum.
Can a post and core fail?
It can, most often by the post loosening or the root fracturing. Good remaining tooth structure and a well-fitting crown reduce the risk.
If you have a heavily broken-down tooth after a root canal, an assessment will show whether a post and core and crown can save it. Book a review and see current options on our offers page, or read our guide on whether a root canal tooth needs a crown.
