When decay has destroyed most part of a tooth, it may also infect its nerves.
Usually the tooth is very painful and this is the most common cause of dental emergency. Root Canal Therapy can save infected tooth. This involves the removal of infected nerves and reconstruction of the defect destroyed by decay.
What is root canal therapy?
Root canal therapy (also called endodontics) is needed when the blood or nerve supply of the tooth (known as the pulp) is infected through decay or injury. You may not feel any pain in the early stages of the infection. In some cases, your tooth could darken in colour which may mean that the nerve of the tooth has died (or is dying). This would need root canal treatment.