The short answer
Some discomfort after root canal treatment (Wurzelbehandlung) is expected: the tissue around the root tip has been disturbed, and it reacts. As a rule, that soreness peaks within the first two or three days and then fades steadily over one to two weeks. The pattern is what matters — pain that is improving is healing, pain that is escalating from day three onwards is not. Swelling of the face, fever, or difficulty opening your mouth or swallowing belong in a different category and should be seen the same day, including at a weekend. This article is about telling those apart and knowing what to do tonight.
What usually happens, and when
The first few hours. The anaesthetic (Betäubung) wears off after two to four hours. As sensation returns, the tooth typically becomes tender to bite on. Many people find the jaw aches from having been open, which is separate from the tooth.
Day one to day three. Discomfort is at its worst here. The tooth feels bruised, is unpleasant to chew on, and may throb mildly in the evening; an ordinary painkiller usually handles it. Sensitivity to touch is common and not a warning sign in itself.
Day four to day fourteen. The line should be heading downwards — not necessarily in a straight line, and not necessarily to zero, but unmistakably towards better. By the end of the second week, most people notice the tooth only when they think about it.
Week three onwards. Occasional twinges on hard biting can persist for several weeks, particularly on a molar. A tooth still genuinely painful a month later is worth investigating rather than waiting out.
Months later. A tooth that settled completely and then starts up again — dull ache, pressure, tenderness to bite, sometimes a small bump on the gum — is telling you something has changed. Rarely urgent that night, but it needs an appointment and an X-ray.
Three different things get called "inflammation"
Lumping them together is why people either panic unnecessarily or wait far too long.
1. Irritation of the tissue around the root tip. Instruments and rinsing solutions work right up to the end of the root, and the ligament just beyond it reacts to being disturbed. This is not an infection. It is sore, it is self-limiting, and it accounts for most discomfort in the first week.
2. A flare-up in the first days. Occasionally a quietly infected tooth becomes acutely painful shortly after treatment begins, typically between appointments, as pressure builds in a space with no easy way out. It is unpleasant and well described in dentistry, and it does not mean the treatment has failed — but it needs attention rather than endurance, because the remedy is to release the pressure.
3. Infection that persists or returns. Bacteria remaining in part of the canal system, or re-entering through a leaking filling or new decay, keep the root tip inflamed. This appears weeks to months later, often with little drama: a tooth that feels different, an ache on biting, sometimes a small pimple-like swelling on the gum that comes and goes. The reasons are covered in Why do root canal treatments fail?.
The everyday distinction is the direction of travel: irritation gets better, infection does not.
The line where it stops being a dental problem
Most flare-ups are dealt with by a dentist on the day. A narrow set of signs, however, belongs in a hospital emergency department rather than a dental chair: swelling that is closing your eye, spreading down the neck or under the tongue, making it hard to swallow or breathe, or a jaw you cannot open more than a couple of centimetres. These are uncommon — and the ones that should never be slept on overnight.
What we actually do when you come in
We work out where the pressure is. Tapping the tooth, checking the bite, feeling the gum, and an X-ray. A tooth that has become tender under a temporary filling behaves differently from one with an abscess forming.
We relieve the pressure if there is any. Depending on the finding, that can mean reopening the tooth and letting it drain, cleaning the canals again, or making a small incision where a collection has formed. Relief is often immediate, and it is the reason to come in rather than wait.
We adjust the bite. A common cause of a tooth that hurts to bite on after treatment is a filling sitting a fraction too high. Reducing it takes a minute, and the difference over the following day is considerable.
Antibiotics — only where they are the right tool. They do not reach inside a root canal in useful concentrations and they do not fix a tooth. They are for infection spreading beyond it: facial swelling, fever, general illness. Dental associations in Germany and internationally have been explicit about not prescribing them routinely.
We reassess the plan if needed. A further cleaning appointment, retreatment later, occasionally a surgical step. That conversation does not have to happen while you are in pain.
Getting through tonight
Until you are seen, a few things genuinely help — and one thing makes it worse.
- Cold, not heat. A cold compress on the outside of the cheek, twenty minutes on and twenty off. Warmth — a hot water bottle, a hot flannel — soothes for a few minutes and encourages swelling to spread. Avoid it.
- Keep your head up. Lying flat increases pressure at the root. An extra pillow often makes the difference between a bad night and a tolerable one.
- Painkillers, taken properly. An anti-inflammatory painkiller generally works better for dental pain than a plain analgesic. Take the dose on the packet at regular intervals rather than waiting for the pain to return, and ask a pharmacist if you take blood thinners, have stomach problems, asthma or kidney disease, or are pregnant.
- Do not chew on it, and stop testing whether it still hurts. It does, and the testing keeps it irritated.
- Never place a painkiller tablet against the gum. It burns the tissue and does nothing for the tooth.
Out of hours in Germany, briefly
Dental pain has a habit of peaking on Friday evening. Germany has an out-of-hours dental service (zahnärztlicher Notdienst) covering nights, weekends and public holidays, organised regionally, with the practice on duty rotating. Two reliable ways to find it: the answering machine of any local practice usually names the current service, and the regional dental association publishes a search by postcode.
When you get through, keep it simple — and it is fine to say it in English:
“I had a root canal treatment on [day]. Since yesterday the pain is getting worse and my cheek is swollen. I have a fever of 38.5. Can I be seen today?”
Three facts do most of the work: what was done and when, what has changed, and whether there is swelling or fever. If your German is limited, say so at the start of the call rather than struggling through — and for routine care afterwards, it is worth registering somewhere that treats in your language. English-Speaking Dentist in NRW explains how we handle that.
We run an out-of-hours service ourselves as part of the local rota.
What is normal — and when to contact us
Situations that lower the threshold
Diabetes. Higher blood sugar impairs the immune response and infections spread more readily. Do not adopt a wait-and-see approach; be seen earlier.
A suppressed immune system — chemotherapy, immunosuppressants after a transplant, high-dose steroids. Same rule, and mention the medication when you call.
Pregnancy. An infected tooth is more of a risk than treating it. Treatment during pregnancy is possible with the appropriate precautions, and pain should not be endured; tell us how many weeks you are.
Blood thinners or bisphosphonates. Neither prevents treatment, but both change how it is planned. Bring your medication list, or a photograph of it. If the tooth has been root-treated once before, the options differ again — see When does a root canal need to be redone?.
Yes, in the sense that mild to moderate tenderness for a few days is expected — the tissue around the root tip has been worked on. What is not normal is pain that intensifies after day three, or any facial swelling. The direction of travel over several days tells you more than the intensity on any single day.
Only if the infection has moved beyond the tooth — facial swelling, fever, feeling ill. For pain confined to the tooth, antibiotics are largely ineffective, because they do not reach inside the canal in useful amounts. The effective treatment is releasing the pressure and cleaning the canal system.
It usually means bacteria have survived somewhere in the canal system, or have re-entered through a leaking restoration or new decay. It is not an emergency in most cases, but it will not resolve on its own. An X-ray and an examination will show whether retreatment, a surgical step or extraction is the sensible route.
Not necessarily. Pain sometimes disappears because pressure has found an escape route — through the gum, for instance — which relieves the symptom without removing the infection. If severe pain vanishes abruptly and something feels changed, have it checked rather than assuming it is over.
After root canal treatment, expect a tooth that is sore for a few days and then steadily less so. That is healing, and it needs nothing more than patience and a painkiller taken properly.
What needs action is a different shape of story: pain that climbs instead of falling, swelling anywhere in the face, fever, or a tooth that flares up again months later. None of these means the treatment was botched, and none is usually dramatic if dealt with early. The mistake that costs people is sitting out a weekend with a swelling because it seemed impolite to phone.
Zahnarztpraxis Tsypin · Wuppertal. This article was medically reviewed and is provided for information; it does not replace an examination. Updated August 2026.
