Signs you may need a root canal
- toothache that throbs, comes on by itself or wakes you at night
- pain from hot or cold that lingers for more than a few seconds after the food is gone
- pain when you bite or press on the tooth
- a gum boil or pimple near the tooth, or a bad taste
- swelling of the gum or face
- a tooth that has gone darker after an injury
Sometimes a tooth needs a root canal without any pain, because the nerve has already died. This shows up on an X-ray.
What happens
- Diagnosis. We examine the tooth, test the nerve and take an X-ray to see the roots and any infection. We’ll also check the tooth is worth saving: enough tooth left to restore, and healthy gum and bone around it.
- Numbing. Local anaesthetic. A rubber sheet (dental dam) isolates the tooth so it stays dry and clean and nothing falls into your mouth.
- Cleaning the canals. A small opening is made in the top of the tooth. The nerve tissue is removed, and the canals are measured, shaped and washed with disinfectant.
- Sealing. The clean canals are filled with a rubber-like material (gutta-percha) and sealed. If the tooth needs a second visit, medicine is placed inside and a temporary filling closes it.
- Rebuilding. A permanent filling, and for most back teeth a crown a week or two later.
Who does your root canal
Dr. Adish Chaudhary also performs root canal treatment. His specialist qualification is in prosthodontics, rather than endodontics. Our team includes an endodontist for root canal care, including complex canals and re-treatment. The treating clinician is confirmed after assessment; ask who will perform each stage before treatment starts.
Crowns after root canal treatment are planned by Dr. Adish Chaudhary, our prosthodontist, so the tooth is rebuilt to last.
After treatment
- Avoid chewing on the tooth until the numbness has gone, and until the final filling or crown is fitted.
- Tenderness on biting for a few days is normal. Take an over-the-counter painkiller you know is safe for you, following the pack.
- A temporary filling can wear down slightly; if it falls out, call us.
- Come back for the crown on time. A root-treated back tooth without a crown is at real risk of cracking.
Risks and limitations
- Not every tooth can be saved. A tooth with a vertical crack, too little structure left or severe gum disease may be better removed.
- Flare-up. Occasionally, pain and swelling increase a day or two after cleaning. It’s treatable, so call us.
- Re-infection. A small proportion of root canals fail, sometimes years later. Most can be re-treated.
- Instrument separation or perforation are uncommon complications, and are one reason complex teeth go to the endodontist.
If you’d rather not keep the tooth, the alternative is extraction, ideally followed by a replacement such as an implant or bridge.
Questions patients ask us
Is root canal treatment painful?
The treatment itself shouldn't hurt, because the tooth is fully numbed. The pain people associate with root canals is usually the toothache before it. Very inflamed teeth, often lower molars, can be harder to numb, and we take extra time and extra anaesthetic until you're comfortable.
Can a root canal be done in one day?
Often, yes. Many teeth can be cleaned and sealed in a single visit of about an hour to ninety minutes. If there's active infection, pus or swelling, or the canals are very curved, it's safer to clean the tooth, place medicine inside and finish at a second visit.
How long does pain last after a root canal?
Tenderness when you bite, for two to five days, is common and settles with ordinary painkillers. Pain that gets worse after a few days, swelling, or pain that lasts beyond a week or two should be checked.
Is a cap (crown) necessary after root canal treatment?
For molars and premolars, usually yes. A root-treated back tooth is weakened by the decay and the access opening, and chewing forces can split it. A crown holds it together. Front teeth with little damage can sometimes be restored with a filling alone.
What are the signs of root canal failure?
Pain on biting that returns months or years later, a gum boil (a small pimple near the tooth), swelling, or a dark area at the root tip on an X-ray. It can often be fixed with re-treatment by an endodontist, or occasionally with minor surgery at the root tip.
Root canal or extraction, which is better?
If the tooth can be restored and the gums and bone around it are healthy, keeping it with a root canal is usually the better long-term choice. Extraction is quicker but leaves a gap that most people then need to fill with an implant, bridge or denture. We'll tell you honestly if a tooth isn't worth saving.
What can I eat after root canal treatment?
Wait until the numbness wears off. Then eat soft food on the other side until the permanent filling or crown is fitted, because the tooth is fragile until then.
Is root canal treatment safe for children?
Children's milk teeth can have a simpler nerve treatment (pulpotomy or pulpectomy) to keep them until they fall out naturally. See root canal treatment for milk teeth.
Sources
NHS: root canal treatment ↗Leeds Teaching Hospitals NHS: root canal benefits, alternatives and risks ↗ADA MouthHealthy: root canals ↗Last updated 18 October 2026. This page explains options in general terms; your own plan comes from an examination.