Root canal treatment

About root canal treatment

In the middle of your teeth there is a core of blood vessels and nerves called pulp. The pulp sits inside a space called the root canal. Each tooth can have one or more root canals. Your front teeth often have just one root canal, whereas your back teeth may have three or more.

The pulp in your tooth can become infected with bacteria if your tooth becomes damaged. This can happen in a number of ways. These include:

  • severe tooth decay
  • an injury, such as a blow to your mouth
  • cracked or loose fillings, or repeated fillings in your tooth
  • gum disease

If the pulp in your tooth becomes infected this can spread to the root canal and your tooth may become painful. If the infection spreads further it can cause a tooth abscess, which is a collection of pus. This can be painful and tender when you bite down on your tooth and can cause swelling around your tooth and jaw. Sometimes your tooth may look darker in colour than your other teeth, which means that the nerve inside your tooth is dead or dying. Without treatment the infection may spread further into your jawbone and you may need to have the tooth taken out.

The aim of root canal treatment is to remove the damaged pulp and the bacteria that are causing the infection. Your dentist will drill a hole into the tooth to the root canal and remove the pulp and infected tissue. He or she will then clean and fill the empty root canal and put a permanent seal over the top of your tooth.

Root canal treatment can save a tooth which would otherwise need to be taken out. When a tooth is removed it can affect how you look and also how well you chew. Although your dentist will remove nerves and blood vessels from your tooth when the pulp is taken out, your tooth will continue to live. This is because the surrounding tissues provide it with the blood and nutrients it needs.

Root canal treatment can often be done in one session, or you may need to have treatment over more than one session. How long treatment takes will depend on how severe the problem is. All dentists can carry out root canal treatment. However, if you need repeated root canal treatment on a tooth that has already had it (this is called re-treatment), or if your tooth is difficult to treat your dentist may refer you to an endodontist, who specialises in root canal treatment.

What are the alternatives?

Sometimes damaged teeth can’t be repaired with root canal treatment. This is usually if your tooth is badly damaged or if you have severe gum disease which prevents your tooth from healing or being well supported after treatment. In this case your dentist may suggest you have the tooth removed (extracted).

Preparing for root canal treatment

Your dentist will ask about your symptoms and examine you. He or she may also ask you about your medical history and any previous treatment you have had on your teeth.

Your dentist will also take an X-ray of your tooth. This can help to show how far any infection has spread, if there is an abscess and how many root canals your tooth has.

Root canal treatment is usually done under local anaesthesia. This completely blocks pain from the jaw area and you will stay awake during the procedure. If you’re concerned about having a local anaesthetic, talk to your dentist.

Your dentist will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will help you to be informed, so you can give your consent for the procedure to go ahead, which you may be asked to do by signing a consent form.

What happens during root canal treatment?

If you need a local anaesthetic, your dentist will give it to you a few minutes before the procedure, to give it time to work. He or she will separate your tooth from the rest of your mouth using a thin sheet of rubber called a dam. This helps to stop the spread of any infection and prevents you from swallowing or breathing in any small instruments or fluids used during the procedure.

Your dentist will make a hole in the top of your tooth and remove the dead or diseased pulp. He or she will then clean out the empty hole using a fluid that also helps to get rid of any infection. The hole in your tooth may need to be widened to make sure it can be filled properly, and is done using small files. This can take several hours and may have to be done over more than one visit. If the root canal is severely damaged, this may be all the treatment you have during your first visit. Your dentist will put a temporary filling in your tooth to keep it sealed until you go back for the next stage of your treatment. However, if your tooth isn’t severely damaged your dentist may put a permanent filling in and seal the tooth. He or she may take an X-ray to check it before your tooth is filled.

If you have a temporary filling, your dentist will remove this and replace it with a permanent one when you go back for your next appointment. He or she will then seal your tooth to prevent infection and further damage. If there is a risk that your tooth may become damaged again your dentist may suggest having a crown fitted. This is an artificial cap that fits over your tooth.

What to expect afterwards

You will usually be able to go home when you feel ready. After a local anaesthetic it may take several hours before the feeling comes back into your mouth.

You may need pain relief to help with any discomfort as the anaesthetic wears off. If you need pain relief, you can take over-the-counter painkillers such as paracetamol. Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist for advice.

Recovering from root canal treatment

Your root canal treatment should be checked by your dentist after a year. You will have an X-ray and your dentist will check for any pain, swelling or signs of infection or damage. You may need to have further checks over the next four years if there is any sign of damage, or if your tooth doesn’t heal properly. Some people need to have further root canal treatment.

After your treatment, it's important to take care of your repaired tooth. Brush your teeth twice a day, floss between your teeth every day and have sugary foods or drinks only at mealtimes. You can also take care of your teeth by visiting your dentist regularly for a check-up.

What are the risks?

As with every procedure, there are some risks associated with root canal treatment. We have not included the chance of these happening as they are specific to you and differ for every person. Ask your dentist to explain how these risks apply to you.


Side-effects are the unwanted but mostly temporary effects you may get after having the procedure.

Cleaning your teeth may cause slight tenderness, but this is only temporary. If you have severe pain or any pain or discomfort that gets worse, see your dentist.


Complications are when problems occur during or after the treatment.

It's unlikely that you will have any further problems after root canal treatment. If your tooth doesn’t heal properly, or becomes damaged or infected, you can have root canal treatment done again. This is called re-treatment.

Will I need to have a crown put on after root canal treatment?


You may need to have a crown fitted over your tooth that has had root canal treatment as it can help to strengthen and protect it from further damage. Crowns are caps made out of a material like porcelain, which fit over your tooth to protect it.


Crowns are used to cover teeth that have been broken, or have been weakened by a large filling, decay or after root canal treatment. If your tooth has been badly damaged, you’re likely to need a crown after root canal treatment.

Your dentist will take an impression of your tooth using a soft, mouldable material. He or she will have your crown made based on the impression to make sure it’s the right shape and size. You will be given a temporary crown while the permanent one is made. This isn’t as strong as a permanent crown but you should still be able to chew your food with it in place.

Your dentist will then fit the permanent crown. He or she will make sure you can bite comfortably with it in and then secure it into place. If a lot of your tooth is missing then your dentist may insert a peg into your root canal to hold the crown in place. It should last for many years if you look after your teeth well. This means brushing your teeth twice a day, flossing between your teeth every day and having sugary foods or drinks only at mealtimes. You can also take care of your teeth by visiting your dentist regularly for a check up. 

I am having root canal treatment. How long will the restored tooth last?


After root canal treatment the restored tooth should last as long as your other teeth. It’s important to look after your teeth and gums and to see your dentist regularly.


Your treated tooth will stay healthy as long as the root is nourished by the tissues around it. This means your tooth could last a lifetime.

After your treatment, it's important to take care of your repaired tooth as you would any other. For good mouth and dental hygiene, follow the points below.

  • Brush your teeth twice a day for two minutes, using a fluoride toothpaste.
  • Floss between your teeth at least once a day.
  • Have small amounts of sugary foods and drinks at mealtimes only.
  • Have regular check ups at your dentist.

Will I have to pay for root canal treatment?


The cost of having root canal treatment varies. Ask your dentist to provide you with a written estimate of the costs involved before you start your root canal treatment.


If you see an NHS dentist, you may be able to get your treatment for free or at a reduced cost. This will vary depending on your circumstances. For example, if you’re under 18, pregnant or receiving certain benefits, you will receive free treatment.

If you see a dentist privately, you will need to pay all of your treatment costs. The costs of private root canal treatment will vary from dentist to dentist. It will also depend on how severe the problem is and the type of tooth being treated.

Ask your dentist for information about costs before you start your treatment.