A tooth root infection is an inflammation inside the tooth that can reach down to the tip of the root. Typical signs are a throbbing pain, often at night, a strong reaction to cold or heat that lingers, and pain when you bite down. It does not heal on its own, not even when the pain suddenly eases. What helps is treating the cause: usually a root canal treatment, which keeps your own tooth.
Updated: 14 November 2026
- A throbbing pain that gets worse at night is the most common sign.
- If the pain suddenly stops, the inflammation is not over.
- An antibiotic alone does not remove the cause. A root canal treatment does.
What lies behind it
Inside every tooth is the pulp, a fine tissue of nerves and blood vessels. If bacteria get in, for example through deep decay, a crack or a leaking filling, it becomes inflamed. Left untreated, the pulp dies and the inflammation moves to the tip of the root and into the bone. In everyday language, both stages are called a tooth root infection.
How to recognise it
| Stage | Typical signs |
|---|---|
| Early | a short, sharp pain with cold or sweet things that fades again |
| Advanced | a constant throbbing pain, also at night. It is often hard to tell which tooth it is |
| Pulp has died | the pain eases. Later the tooth hurts when you bite and feels slightly too high |
| Spreading | the gum or the cheek swells |
Sometimes it all happens without pain, and only an X-ray shows the inflammation at the root tip.
“The pain is suddenly gone. Doesn't that mean it's over?”
No. When the pain disappears from one day to the next, the pulp has usually died. The bacteria stay in the tooth, and the inflammation continues at the root tip, often unnoticed for weeks. This is exactly when the tooth can be treated well, calmly and without acute pain.
Does an antibiotic help?
Not on its own. An antibiotic hardly reaches the inside of the tooth, and the cause remains. Research reviews show no clear benefit against the pain when the pulp is inflamed. An antibiotic is added when the inflammation spreads, for example with swelling and fever.
What helps until your appointment
- A painkiller from the pharmacy. Ask the pharmacist for advice, or ask us.
- Cool from the outside: an ice pack wrapped in a cloth, a few minutes at a time, then a break.
- Chew on the other side.
- Warmth does the tooth no good right now.
Read more in “Toothache: when should you see a dentist?”.
That is how many teeth were still in place eight years after root canal treatment. An analysis of 1.46 million teeth.
Salehrabi and Rotstein, Journal of Endodontics, 2004How your tooth is saved
With digital X-rays and under the microscope, we check how far the inflammation reaches. During the root canal treatment we remove the inflamed tissue, clean the fine canals at up to 25x magnification and seal them tightly. You feel touch, but no pain. Often the pain you came in with eases after the first session. You can read how it works in “What happens during root canal treatment?”.
Is the tooth hurting right now? Book a toothache appointment or call us.
Book onlineWhen it is urgent
If your cheek swells, you get a fever, swallowing becomes difficult or you can hardly open your mouth, contact us the same day. Outside our opening hours, contact the dental emergency service or the emergency department of a hospital.
