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Endodontics: what happens during a root canal?
Root canal treatment removes infection from inside a tooth. It can save a tooth that might otherwise need to come out.
This is general information, not a diagnosis. It does not replace a check by a dentist or doctor. If you are worried, contact a dental professional.
Why it is needed
The soft middle of the tooth (the pulp) can get infected. Causes include decay, gum disease, a cracked tooth, or an abscess.
Step by step
- You get a numbing injection. You stay awake but should not feel pain.
- The dentist makes a small opening in the tooth.
- The infected pulp is taken out. Any abscess is drained.
- The inside is cleaned and shaped.
- The tooth is filled and sealed.
- It usually takes 2 or more visits. Each can last 1 to 2 hours.
- You may have a temporary filling between visits.
- A crown (a cap) may be needed if the tooth was badly damaged.
Afterwards
- Your face may feel numb for a few hours.
- The area may feel sore or swollen. It should get better within a couple of weeks.
- Take paracetamol or ibuprofen if needed, and go to follow-up visits.
When to see a dentist
- Pain or swelling gets worse instead of better.
⚠ Get emergency help now if you have
- Swelling near your eye, or in your neck.
- Swelling that makes it hard to breathe, swallow or speak.
- You cannot open your mouth, or there is a lot of swelling inside it.
Call your local emergency number or go to an emergency department now. Do not drive yourself.
Related: Crowns and other replacements · All dental treatments
Sources
Paraphrased in plain words. Links checked and accessed 21 Oct 2026.
- NHS (UK). “Root canal treatment”. https://www.nhs.uk/tests-and-treatments/root-canal-treatment/ (accessed 21 Oct 2026).
- NHS (UK). “Dental abscess”. https://www.nhs.uk/conditions/dental-abscess/ (accessed 21 Oct 2026).