When the nerves inside the tooth get infected or die, a toothache results. A patient may opt to have the tooth removed or have a root canal to save it. Probably the most feared of all dental procedures, a root canal is actually not painful itself. The pain is due to the condition of the tooth. To avoid pain, the dentist applies emergency treatment first and dulls the pain with anaesthesia.

To perform a root canal, the dentist cleans the bacteria from inside the roots, emptying the canal. The nerve is only useful to nourish the tooth when it first emerges; but when the tooth is already mature, the nerve is no longer useful so it can be removed. Once the nerve is taken out, a sealant is then applied to fill the canal and prevent bacteria from getting in. An improperly filled canal may result in infection.