Root canal treatment (also called endodontic treatment) removes infected or damaged tissue from inside a tooth. Every tooth has one or more narrow channels running through its root, called root canals. These contain the dental pulp — the soft tissue made up of nerves and blood vessels.
When the pulp becomes infected or inflamed, it cannot heal on its own. Root canal treatment cleans out the canals, disinfects them, and seals them. This allows you to keep your natural tooth rather than having it removed.
Why might I need root canal treatment?
The pulp inside a tooth can become infected or damaged for several reasons:
Deep decay — bacteria from a large cavity reach the pulp
A cracked or fractured tooth — allows bacteria to enter the tooth
Repeated dental work — multiple fillings on the same tooth can irritate the pulp over time
Trauma — a knock or injury to a tooth can damage the pulp, sometimes months or years later
Common symptoms include: severe toothache, sensitivity to hot or cold that lingers, a dark change in colour of the tooth, swelling of the gum near the tooth, or a recurring pimple on the gum. Sometimes there are no symptoms at all and the problem is found on an X-ray.
What are my alternatives?
The main alternative to root canal treatment is tooth extraction. Once the pulp is infected, the only other option is to remove the tooth entirely.
Root canal treatment — saves your natural tooth. A natural tooth is almost always preferable to an artificial replacement.
Extraction — removes the tooth. This ends the infection quickly but leaves a gap. Tooth replacement options (implant, bridge, denture) add further cost and procedures.
No treatment — a dental infection will not resolve without treatment. It is likely to spread, cause increasing pain, and may require emergency treatment. Leaving an infected tooth untreated is not a safe option.
Your dentist will help you understand which option is most suitable for your tooth and your circumstances.
What does root canal treatment involve?
Root canal treatment is usually carried out over one or two appointments. Here is what to expect:
Local anaesthetic — the tooth and surrounding area are numbed. Contrary to its reputation, most patients find root canal treatment no more uncomfortable than having a filling.
Rubber dam — a thin rubber sheet is placed around the tooth to keep it clean and dry during treatment.
Access opening — your dentist makes a small opening through the top of the tooth to reach the root canals.
Cleaning and shaping — very fine instruments are used to remove the infected pulp and clean each canal. Disinfecting solutions are used to flush the canals.
Temporary filling — if the treatment is carried out over two appointments, a temporary dressing is placed to keep the tooth clean between visits.
Root filling — once the canals are clean and dry, they are filled and sealed with a rubber-like material called gutta-percha, along with a sealing paste.
Restoration — in most cases, a crown is recommended after root canal treatment to protect the tooth from cracking, as root-treated teeth can become more brittle over time.
Risks and possible complications
Root canal treatment has a high success rate — studies suggest around 85–95% of root-treated teeth remain functional after 10 years. However, like all dental treatments, there are some risks.
Common (affect more than 1 in 10 people):
Soreness and tenderness around the tooth for several days after each appointment
Mild swelling of the gum
Uncommon (affect about 1 in 10 to 1 in 100 people):
Treatment may not fully resolve the infection, requiring a further course of treatment or a minor surgical procedure (apicoectomy)
A fine instrument may occasionally separate inside a root canal. Your dentist will advise you if this happens and discuss options.
Rare (affect fewer than 1 in 100 people):
Perforation of the root during treatment
An allergic reaction to materials used (very uncommon)
Late failure of the root canal, requiring re-treatment or extraction years later
Even with successful treatment, a root-filled tooth may not last a lifetime. Regular check-ups and good oral hygiene are essential for long-term success.
What to expect after treatment
It is normal for the tooth to feel tender or sore for a few days after root canal treatment. This is usually manageable with over-the-counter painkillers such as ibuprofen or paracetamol taken as directed.
Avoid chewing on the treated tooth until it has been permanently restored with a crown or filling
Continue brushing and flossing normally
Attend your follow-up appointment — this is important to confirm healing and to place the permanent restoration
Contact the practice if you experience severe pain not controlled by painkillers, increasing swelling, or a high temperature.
Questions to ask your dentist
How many root canals does this tooth have, and how straightforward is this likely to be?
How many appointments will I need?
What are my chances of keeping this tooth long-term?
Will I need a crown afterwards, and how soon?
What are the signs that treatment has not worked?
This leaflet is for general information only and does not replace professional dental advice. It is intended to support — not replace — the discussion with your dentist about your individual options, risks, and treatment plan. Treatment outcomes vary between patients depending on individual circumstances. Your dentist will confirm exact fees and what is suitable for your specific circumstances before you agree to any treatment.
When to Seek Urgent Help
If you develop severe swelling of the face, neck, or floor of the mouth, difficulty breathing or swallowing, or a high fever, go to A&E immediately or call 999. Dental infections can spread rapidly and become serious.
References
Aligned with guidance from: SDCEP, FGDP(UK), NICE, British Endodontic Society.