When a cavity has reached the pulp where the nerve lies, the dentist proceeds to heal the tooth with a root canal in order to avoid a bacterial infection. Once the bacteria have penetrated the pulp, the tooth must be devitalized.
A tooth that has had a root canal becomes fragile, and is at risk of breaking. It is recommended to restore such a tooth with a crown or at least a dental post to give it solidity.
Video Animation of a root canal
Circumstances where we need a root canal
- A deep cavity that has reached the dental pulp where the nerve is.
- A broken tooth where a filling is not enough to restore it.
- Pulp is irritated by a trauma.
- Pulp is irritated by a filling that is too deep.
- A tooth needing a crown but needing the additional support of a post.
- Periapical lesion, meaning an infectious lesion that is located at the tip of the root of a tooth that can be seen on an x-ray.
Steps in the preparation of a root canal
- The dentist does the local anesthesia.
- Elimination of the cavity and of the living tissues inside the tooth (dental pulp).
- Cleaning of the inside of the tooth by a mechanic action: scratching of the interior of the pulp canals using manual or rotary endodontic files, and irrigating with a disinfectant.
- Sealing the canal, meaning permanently filling the canals of the tooth. The material that's the most often used is the heated gutta percha (isolating polymer that is very biocompatible) used in conjunction with a root canal sealer.
- Placing of the dental post and restoring the tooth either with a filling or a crown. Some dentists prefer not using a post.
Success rate and complications
Root canals have a very good success rate: over 95%. If well maintained, the teeth that have had root canals can last a lifetime.
In spite of all the efforts that the dentist puts into cleaning and isolating the canals of a tooth, new infections can arise.
The rare reasons (5%) that can complicate a root canal are:
- More canals are present in the tooth and were not found.
- A fracture in the root that was not detected.
- A separation of a piece of the cleaning instrument used by the dentist and that stays inside the canal. In these cases, the tooth can stay asymptomatic, or can lead to a complication.
Following a complication, a tooth can be retreated with a second root canal. It can also have an apectomy which consist of surgically removing the part of the root that is infected at it's end (apex) through the gum. In the case where none of the treatments have healed the complication, tooth extraction will be considered.
A tooth that has had a root canal can decay just like the other teeth. It is therefore important to continue good oral hygiene to keep this tooth for a long time. In addition, it is recommended to restore a devitalized tooth with a crown in order to make it solid.
Cost of a root canal
The price of a root canal can vary depending on the number of canals a tooth may have, and of which part of the country we live in. In general, the cost varies between 800$ and 1,500$, including the dental post and filling. The price of the crown is excluded.
Ordre des Dentistes du Québec (www.odq.qc.ca)