How root canal treatment is performed 

Root canal treatment is carried out by your dentist over two or more appointments.

Unless you're entitled to free NHS dental treatment, you will have to pay for root canal treatment.

You should find out about costs before you start treatment. Read our page on NHS dental services for more information about dentists and treatment costs.

If the work is particularly complex, your dentist may refer you to a specialist in root canal treatment, known as an endodontist.

All registered dental specialists in the UK are listed on the website of the General Dental Council (GDC). You can search the register for a specialist.

Preparation

Before having root canal treatment, your dentist may take a series of X-rays of the affected tooth. This will allow them to build up a clear picture of the root canal and assess the extent of any damage.

Root canal treatment is usually carried out under local anaesthetic (painkilling medication that numbs a specific area of the body). In some cases, where the tooth has died and is no longer sensitive, it may not be necessary to use a local anaesthetic.

Occasionally, teeth may be difficult to anaesthetise. On these occasions, your dentist can use special local anaesthetic techniques to ensure your treatment isn't painful.

Removing the pulp

Your dentist will place a rubber sheet (dam) around the tooth to ensure it is dry during treatment. The dam will also prevent you swallowing or breathing in any chemicals the dentist uses.

Your dentist will open your tooth through the crown – the flat part at the top – to access the soft tissue at the centre of the tooth (pulp). They will then remove any infected pulp that remains. 

If you have a dental abscess (a pus-filled swelling), your dentist will be able to drain it at the same time.

Cleaning and filling the root canal

After the pulp has been removed, your dentist will clean and enlarge the root canal so it can be easily filled. The root canal is usually very narrow, which makes it difficult to fill.

Your dentist will use a series of small files to enlarge the canals and make them a regular shape so they can be filled. This part of the treatment may take several hours to complete and need to be carried out over a number of visits.

Your front incisor and canine teeth (biting teeth) usually have a single root containing one root canal. The premolars and back molar teeth (chewing teeth) have two or three roots, each containing either one or two root canals. The more roots a tooth has, the longer the treatment will take to complete.

If the treatment needs to be carried out over several sessions, your dentist may put a small amount of medication in the cleaned canal in between visits to kill any remaining bacteria. The tooth will then be sealed using a temporary filling.

If you have symptoms from the infection, such as a raised temperature or large swelling, you may be given antibiotics to help manage and prevent further infection.

Sealing and fixing the tooth

At your next visit, the temporary filling and medication within the tooth will be removed and the root canal filling will be inserted. This, along with a filling, will seal the tooth and prevent re-infection.

Root-filled teeth are more likely to break than healthy unrestored teeth, so your dentist may suggest placing a crown (see below) on the tooth to protect it.

In some cases, a root-filled tooth may darken, particularly if it has died due to an injury, such as a knock to the tooth. There are several ways your dentist can treat discolouration, such as whitening the tooth using chemicals.

Crowns

A crown is a cap that completely covers a real tooth. It might be necessary to use a crown after root canal treatment to prevent the tooth fracturing.

Crowns can be made from:

  • metal or porcelain (or both)
  • a ceramic material
  • powdered glass

The size of your tooth will be reduced and the crown will be used to replace what's removed. A mould of your tooth will be taken to ensure the crown is the right shape and size, and fits your tooth accurately.

When fitting the crown, cement will be used to glue the crown to the trimmed-down tooth. If there's only a small amount of tooth left after the root canal treatment, a post can be cemented in the root canal and used to help keep the crown in place.

Read more about what NHS dental fillings and crowns are made of.

Results

Root canal treatment is usually successful at saving the tooth and clearing the infection.

One review of a number of studies found that 90% of root-treated teeth survived for 8-10 years. The study also found that having a crown fitted to the tooth after root canal treatment was the most important factor for improving tooth survival rates.

If you practise good oral hygiene, your treated tooth should survive for a long time. The survival of your tooth depends on a number of factors, including:

  • how much of the natural tooth remains
  • how well you keep your teeth clean
  • the biting forces on the tooth

If an infection does return, however, the treatment can be repeated. Alternatively, if treatment has already been carried out to a high standard and the infection remains, a small operation to remove the root tip (an apicoectomy) may be carried out to treat the infection.

Read more about recovering from root canal treatment.

Page last reviewed: 23/07/2014

Next review due: 23/07/2016