Root Canal Filling


What is it?

The treatment of infection or irreversible inflammation of a tooth nerve (‘pulp’) by the removal of the pulp from the root canals of the tooth.

Diagram of a Root Canal Filling

root filling diagram

What is it for?

When a tooth becomes infected (typically as a result of deep decay – either a large cavity or deep filling), the nerve cannot be repaired by the body’s immune system. The infected nerve must be removed from the root canals, and the canals disinfected and sealed to clear the infection and prevent it from returning. Some dental infections cause toothache which may be very mild to very severe. However, many dental infections are pain free, and you may know nothing about an infection until your dentist spots the signs.

What does the procedure involve?

First, the tooth will be numbed with local anaesthetic. A small hole will be made in the biting surface of the tooth to allow access to the nerve. Over 1 or 2 appointments, the dentist will spend time identifying the root canals, removing the nerves, cleaning, shaping and disinfecting the canals. Front teeth usually have 1 canal. Back teeth usually have 3, so the treatment usually takes longer for back teeth. Usually for this procedure, a ‘rubber dam’ (a small rubber sheet) will be placed over and around the tooth to isolate it from the rest of the mouth, allowing more effective disinfection. Once all the canals have been thoroughly treated, they are sealed with a rubber-type material, and the access hole filled. Root-filled teeth become more brittle, so it is often necessary to have a crown fitted to the tooth to improve the structural integrity. Your dentist will inform you if a crown is recommended.

What are the alternative treatments?

How long will it last?

There is no guarantee that any root canal filling will successfully clear an infection. Success rates vary from 50-90% over 5 years depending on the conditions. It is possible that any root-filled tooth may become re-infected at any time in future. Your dentist will inform you if the tooth is particularly compromised.

Pros and Cons



Saves an infected tooth Not guaranteed success
Tooth is inevitably weaker after treatment
Tooth may darken after treatment