Once a dentist or endodontist has completed a root canal procedure on a tooth, it is then necessary to seal that tooth. This is either done with composite resin, the placement of a dental crown, or the insertion of a post crown. A post crown consists of a porcelain cap attached to a post. This post is inserted into the root canal of a tooth, then surrounded with composite resin to provide a stable core for the dental crown.
If the thought of having a post inserted into your tooth bothers you, then you may be wondering why it is necessary.
A Dental Crown Needs a Stable Core
When dental crowns were first invented by Charles Land, back in 1903, it then became possible for damaged teeth to be saved rather than removed. Once the infection is removed via root canal therapy, a porcelain crown can be placed over the tooth to strengthen it and improve its appearance.
However, when teeth are severely decayed or damaged, a standard dental crown is not a viable option. A dentist has two options when very little tooth structure remains. They can either use composite resin to create a core of filling material, or they can insert a post into the root canal of the tooth.
Composite Resin Cores Are Weak
Although composite resin is great at shoring up small chips, fractures, or areas damaged by decay, it is not strong enough to provide a suitable core upon which a dental crown can be placed. If only 15% of a tooth remains above the gum line for instance, a huge amount of composite resin will be needed to serve as the core. This could make the situation worse.
If composite resin fillings need to be replaced every 5-8 years, and are supported by substantial natural tooth, the life of a mainly composite resin core will be considerably shorter. With no natural tooth to provide support, and with it being subjected to chewing forces each day, the post may break inside the dental crown.
Fibre-Reinforced Resin Posts Are the Answer
The answer then, is to insert a fibre-reinforced resin post into the root canal, cement it in place and then add the dental crown. These posts are also sometimes made of metal. Where they differ in terms of reliability to solely composite resin cores is that they provide a far stronger and stable core for the dental crown to rest upon. If you were constructing a building, for instance, you would opt to support it with steel-reinforced concrete, not concrete on its own.
A post crown gives patients the chance to use teeth that would otherwise be extracted, and they can last for up to 15 years. If you have a tooth that looks impossible to save, a post crown could be the answer.