Sensitivity with swelling or a bad taste: signs of infection that need treatment.

Tooth sensitivity that comes with swelling, a bad taste, a spot on the gum that weeps, or a temperature is a sign of infection, and a dental abscess needs urgent treatment from a dentist because, in the NHS's words, it will not go away on its own¹. Ask your dental practice for an urgent appointment today or contact NHS 111, and call 999 or go to A&E if swelling reaches the eye or neck, fills the mouth, or makes breathing, speaking or swallowing hard¹². A sensitivity toothpaste such as S3 Sensitivity Science™ is an everyday paste, not a treatment. Nothing in a tube treats an infection: a dentist does, by draining the pus and dealing with the tooth or gum it came from¹.

What was checked9 peer-reviewed studies and reviews, the NHS, NICE Clinical Knowledge Summaries and the Oral Health Foundation

When do swelling or a bad taste mean infection?

When they turn up alongside pain in a tooth or the gum, because together they are what the NHS describes as a dental abscess: pus that has collected in a tooth or the gum because of an infection¹. The signs it gives read like this page's title. There may be a bad taste, a swollen face or jaw, glands up on each side of the neck, a high temperature, redness in the mouth or on the face, trouble opening the mouth to chew, and intense pain in the tooth or gum¹.

Sensitivity belongs on that list as well. The NHS names sensitivity to hot or cold food and drink in the affected area among the symptoms of an abscess¹, so a tooth that twinges and also tastes foul is one picture, not an ordinary sensitive tooth with something extra. The Journal's short piece on why teeth suddenly become sensitive covers the everyday causes; this page is for the version with swelling or a taste in it.

NICE's Clinical Knowledge Summary, which is written for GPs and other clinicians, describes how an abscess tends to unfold. The pain usually starts suddenly and gets worse over a few hours to a few days, often with an unpleasant taste, a fever and a general feeling of being unwell; some people find it hard to open the mouth or to swallow³. A clinician examining the mouth may find facial swelling, swollen lymph nodes, a tooth that sits slightly high and is loose and tender, or gum that is swollen, warm and leaking pus³. The spot on the gum that weeps, or keeps coming back, can be a small channel draining the infection: CKS lists a tract that discharges into the mouth or onto the skin among the complications of an abscess⁶.

There are three common routes, and telling them apart is the dentist's job, though knowing them helps the rest of this page make sense.

From inside the tooth. The commonest kind, a periapical abscess, starts in the pulp at the centre of the tooth and usually follows decay³. An inflamed or dead pulp, or an infected root canal, is where this kind of infection comes from, as the 2024 Cochrane review sets out in its background⁴. Decay is the usual way in; an injury is another, according to the NHS¹, and a crack can get there slowly: of 199 cracked teeth whose pulp was judged recoverable in a Singapore retrospective cohort clinical study, nearly three in ten had moved on to an irreversibly inflamed or dead pulp within three years⁷. How pain is described hints at where it sits, though only an examination can say. In a cross-sectional clinical study of 228 people with acute toothache, those whose tooth hurt when tapped more often called their pain throbbing and spreading, and rated it higher⁸.

From the gum. A periodontal abscess forms in the tissues that hold the tooth in place, between tooth and gum, and goes with long-standing gum disease³. A 2014 review in Periodontology 2000 calls it a relatively frequent dental emergency that can put the tooth's future at risk, and notes that its bacteria can spread to other parts of the body⁹. The NHS lists a bad taste, bad breath, shrinking gums, loose teeth and an abscess among the places gum disease can lead¹⁰.

Around a back tooth coming through. When a wisdom tooth has broken through the gum but has no room to come up fully, the flap of gum over it can become infected. The NHS calls this pericoronitis and lists it, with pain, swelling and an abscess, among the problems such a tooth causes¹¹. A 2021 paper that combined a narrative review of guidance with a systematic review of prescribing describes pericoronitis as pain, redness and swelling of the gum around the tooth, sometimes with bad breath or a bad taste, and treats fever, facial swelling, difficulty swallowing and a mouth that will not open fully as signs of a more severe course¹².

Not every swelling near the jaw is a tooth. The alternatives CKS asks clinicians to consider include mumps, sinusitis, a middle-ear infection, facial cellulitis, a quinsy, glandular fever, a salivary gland stone or infection, a jaw-joint disorder and, less expected, acute coronary syndrome¹³. Sorting those out takes an examination, which is one more reason to be seen and not to guess. The guide to sharp-and-brief versus dull-and-lingering pain sets out the patterns that point away from ordinary sensitivity.

Which door: an urgent dentist, NHS 111, or A&E?

For most people with these signs the door is an urgent dental appointment, reached through their own practice or NHS 111, and for a smaller set of signs it is A&E or 999¹².

The A&E signs are about breathing, the eye and how far the swelling has travelled. The NHS dental abscess page lists difficulty breathing, speaking or swallowing, a swollen or painful eye or eyesight that suddenly changes, a lot of swelling inside the mouth, and a mouth that is hard to open¹. Its toothache page adds swelling in the area around the eye or in the neck². Get there without driving yourself: ask someone to take you, or call 999 for an ambulance, and bring any medicines you take¹.

Those are the plain-language versions of what NICE tells clinicians about sending someone with an abscess to hospital as an emergency. Its list covers signs that the airway is affected, a high temperature with a racing pulse or low blood pressure, marked swelling below the jaw or under the eye, swelling in the floor of the mouth, infection spreading across the face or around the eye, drowsiness, headache or changes in the eyes, and dehydration¹⁴. Those are for a clinician to judge. The NHS lists above are the ones written for you.

Everything short of that is an urgent appointment. Call your own dental practice first; if it is closed, the answerphone may say what to do. If you have no dentist, or cannot get an emergency slot, call 111 or use 111 online, which can tell you where to get help, and ask nearby practices whether they can see you as an emergency¹. The NHS says urgent dental treatment should be offered within 24 hours or seven days, depending on the symptoms¹⁵. The Oral Health Foundation puts a clock on swelling: a swollen face, swelling that keeps growing, or a lot of pain should mean same-day care from a dentist, and swelling that affects breathing, swallowing or sight, spreads towards the eye or neck, or arrives with a fever and severe pain means emergency medical care¹⁶.

One inconsistency is worth knowing about. Read on its own, the NHS toothache page files a swollen jaw, a fever or a foul taste under advice to see a dentist, without the word urgent². The NHS abscess page describes those same signs and tells anyone who thinks they have an abscess to ask for an urgent appointment or contact NHS 111¹. This page follows the abscess page.

The table sets each sign beside its door, what the NHS suggests while you wait, and the page it comes from. No product appears in it, because none belongs there.

Painkillers that work are not a reason to cancel. The NHS list of reasons for an urgent appointment includes pain that painkillers help but that is not going away¹⁵, and NICE asks clinicians to remind people that painkillers should not be used to put off dental treatment¹⁴. If you are not sure whether A&E is the right place, the NHS suggests calling 111 or using 111 online to find out¹⁵.

What does not treat a dental infection?

Anything that leaves the source where it is: for most people that includes a course of antibiotics on its own, a GP appointment, a rinse, a mouthwash and a toothpaste. NICE's advice to clinicians is that definitive treatment can only be given by a dentist and that medication will not get rid of the source of the infection¹⁴.

Antibiotics are the hardest of these to believe. For otherwise healthy people at low risk of complications, with no signs of spreading infection, CKS says antibiotics are generally not indicated³. It names the exceptions in the same passage: people who are unwell in themselves or show signs of severe infection, such as fever, swollen lymph nodes, cellulitis or diffuse swelling, and people at high risk of complications, for example because they are immunocompromised or have diabetes³. Even for them an antibiotic is a bridge, not the treatment. CKS tells clinicians not to switch to a different antibiotic when the first one fails, but to send the person for urgent dental treatment¹⁴. Whether any particular person needs one is a decision for the dentist or doctor who examines them, and this page gives no advice about which antibiotic or how much.

The trials behind that position are few and small. A 2024 Cochrane systematic review found three randomised trials, with 134 adults in all, of antibiotics given alongside dental treatment for an infected or inflamed area at the root of a tooth⁴. A single dose of clindamycin before root canal work made little to no difference to pain or swelling, on low-certainty evidence⁴. A week of penicillin after the dental procedure, in adults with an acute abscess, showed no difference either, and the certainty of that evidence was very low⁴. No trial in the review compared antibiotics with a placebo when no dental procedure was done at all⁴. The review's own background notes that guidelines put removal of the source first and keep antibiotics for spreading infection or a fever and malaise, and that dentists often prescribe them without those signs⁴.

A GP surgery is the wrong door for a tooth. The NHS says not to go to a GP with a dental abscess, because a GP will not be able to give dental treatment¹. What the GP door tends to produce instead has been counted. In a retrospective cohort study of 288,169 consultations for dental problems in UK general practice between 2004 and 2013, an antibiotic was prescribed in 57.1% of them⁵. The study counted prescriptions, not diagnoses, and its data end in 2013⁵. A prescription still leaves the pus where it is.

Rinses and pastes are not on any treatment list. The NHS toothache page suggests a salt-water rinse for adults, a pain-relieving gel and soft food as ways to ease pain while waiting for an appointment, and the abscess page lists painkillers, soft food and a soft toothbrush; both frame them as things to do while you wait²¹. NICE's summary says it found no evidence that looked specifically at self-care in the treatment of a dental abscess¹⁴. A PubMed search run for this page in September 2026, pairing dental abscess, periapical abscess or odontogenic infection with salt water, saline, mouthwash, mouthrinse, chlorhexidine or home remedy, returned eleven records. None tested a rinse or a mouthwash as a way of treating an abscess; the rinses and irrigations that did appear were used by clinicians during drainage or root canal work. The Oral Health Foundation states the limit plainly: pain relief can ease discomfort, but it does not fix the cause of toothache¹⁶.

The same is true of toothpaste, a sensitivity paste included. No guidance page read for this article lists one as a treatment for a dental infection, and this page does not suggest one.

Should you keep using a sensitivity toothpaste like S3 while you wait for treatment?

Keep cleaning your teeth, gently and with a soft toothbrush, because that is the NHS advice for the wait; a change of paste is not part of it¹. If the paste you already use is S3, carry on with it as the everyday toothpaste it is meant to be. No toothpaste has a role in treating a dental infection, S3 included, and this page will not suggest one for the wait.

Two reasons sit behind that. The first is target and timing. Desensitising pastes are designed for the short, sharp twinge of exposed dentine in a healthy tooth, and their effect is judged over weeks of twice-daily brushing; an abscess is a collection of pus, and what treats it is a dentist draining it¹. The second is what a quieter twinge would tell you, which is nothing. Sensitivity to hot or cold in the affected tooth is itself one of the NHS abscess symptoms¹, and dulling it says nothing about the infection underneath. The signs that matter here are swelling, taste, temperature and whether the mouth opens, and no paste changes those.

What the NHS does suggest for the wait is short. Take ibuprofen or paracetamol, with a pharmacist's advice if you are unsure, and remember that children under 16 should not take aspirin². Do not take more than the recommended dose of any painkiller: a higher dose does not make it work better and can cause harm¹. Many over-the-counter remedies contain the same painkillers, so NICE advises clinicians to warn people against taking combinations of products at once without checking with a healthcare professional or the packet¹⁴. Eat soft food such as soup, scrambled eggs, mashed potato or yoghurt, and keep away from food and drink that is very hot or very cold¹. The toothache page adds not flossing around the sore tooth, chewing on the other side, and a salt-water rinse for adults². All of that is for comfort. The guide to what helps tooth nerve pain tonight goes further into painkillers and what the evidence says about them, and the page on tooth pain at night covers pain that wakes you.

What happens at the appointment, and what if you cannot get one?

The dentist drains the pus and deals with where it came from, under local anaesthetic, so you should not feel the procedure itself¹. If a problem with the tooth caused the abscess, that means root canal treatment or taking the tooth out; you may be offered painkillers for a few days afterwards, and sometimes antibiotics¹. NICE's background for clinicians notes that an acute dental abscess usually responds well to this local treatment, whether root canal treatment, extraction, or cutting and draining the swelling¹⁴. When the pain is a lingering ache from the pulp without swelling, the page on sensitivity that lingers after the trigger has gone explains what root canal treatment is for.

A gum abscess follows the same principle. The 2014 review describes its treatment as drainage and cleaning of the tissue, with the need for antibiotics weighed case by case on local and general factors, and the gum disease behind it treated once the acute phase is under control⁹. For an infected gum flap over a wisdom tooth, the 2021 review says most cases settle with local care from a clinician, which means irrigating and cleaning under the flap and draining any pus, with antibiotics kept for severe cases where the infection is spreading or the whole body is affected¹². In the systematic review part of the same paper, which included 11 studies, almost three quarters of the dentists surveyed said they prescribed antibiotics for pericoronitis, a gap between practice and guidance that its authors call overuse¹². A wisdom tooth that cannot come through and keeps causing trouble may need to come out, and a dentist may remove it or refer you to a specialist¹¹.

On the NHS in England, as shown on nhs.uk on the tenth of September 2026, an urgent appointment costs £27.90 and can include an examination, X-rays, a temporary filling, emergency partial root canal treatment, removal of up to two teeth, and aftercare including treatment for infections¹⁷. A full course that includes root canal treatment or an extraction falls in Band 2, at £76.60¹⁷. Some people pay nothing, charges change, and Scotland, Wales and Northern Ireland set their own; the page on free and low-cost NHS dental options sets out who pays what and how the routes work.

If you cannot get an appointment, keep using NHS 111, which can tell you where help is available, and ask nearby practices whether they can see you as an emergency¹. A pharmacist can advise on painkillers while you wait¹⁵. And if the swelling spreads, or any sign from the A&E list appears, the door changes to 999 or A&E, whatever the time or day¹².

Why does it matter to go early?

Because an abscess does not go away on its own, and NICE's background for clinicians says the local treatment should be carried out as soon as possible to keep the risk of complications down¹¹⁴. An infection left in place can spread, and CKS lists where it can go: into the sinus above the upper teeth, the skin and tissues of the face and around the eye, the jaw bone, the spaces of the neck and the floor of the mouth, and, rarely, into the bloodstream as sepsis⁶. Spread is more common in people who are immunocompromised and in older people, CKS adds, and the tooth itself can be lost⁶. That list is why the A&E signs are about breathing, swallowing and the eye.

The UK has counted who reaches hospital. A national audit of maxillofacial surgery units over two months in 2006 recorded 266 episodes of severe infection of the face and neck that started from a tooth; 81% of the patients were admitted, and 46% needed an operation under general anaesthetic¹⁸. With hospital treatment, 89% made a full recovery and 3% recovered with complications, and the audit reported no deaths¹⁸. Half had been referred by A&E, and 47% had not sought help from dental services for that episode¹⁸. Of the patients treated by primary care dental services, about two thirds had been given antibiotics with no procedure, which the audit's authors call an inadequate level of treatment for an infection from a tooth¹⁸. It is one two-month snapshot from 2006, and it counts people who were already in hospital¹⁸.

A prospective clinical study from Finland looked at the route into hospital. In that clinical study, of 88 adults admitted to one university hospital with a dental infection over a year, two thirds had already made health-care visits for the same infection, nearly half had started treatment beforehand, half of that treatment was antibiotics alone, and the tooth or site causing the infection had been identified before admission in only half¹⁹. The study did not time those steps and cannot show that any of them caused an admission¹⁹. A PubMed search run for this page in September 2026, pairing dental abscess or odontogenic infection with delay or time to treatment and with admission, spread or complications, returned forty-four records, most of them case reports. None set how long people waited against how often their infection spread, so this page gives no figure for what a day's delay changes.

The numbers have also moved over time. An analysis of NHS data published in the British Dental Journal in 2025 describes a steady rise over twenty years in NHS hospital admissions in England for severe dental infection, a fall at the start of the COVID-19 pandemic, and admissions still below their pre-pandemic level at the end of its 2018 to 2023 data²⁰. Those are population trends. They say nothing about what will happen to your own tooth, and the reason to use the urgent door today is simpler: the NHS says an abscess needs a dentist, and a dentist is the one who can drain it¹.

Frequently asked questions

Can S3 or a mouthwash clear a gum infection?

No. S3 is an everyday sensitivity toothpaste, not a treatment, and neither a toothpaste nor a mouthwash is among the things the NHS and NICE say treat a dental abscess: drainage by a dentist and, where the tooth is the cause, root canal treatment or extraction¹¹⁴. For a gum abscess, the 2014 review in Periodontology 2000 describes treatment as drainage and cleaning of the tissue by a clinician⁹. A rinse cannot drain an abscess, and draining it is the step that treats it¹.

Will a dental abscess go away on its own?

No. The NHS says a dental abscess will not go away on its own and needs urgent treatment by a dentist¹. A spot on the gum that leaks from time to time can be a channel from the infection, which CKS lists among the complications of an abscess, and a spot that drains is not an infection that has cleared⁶.

Can I get antibiotics from my GP instead of seeing a dentist?

The NHS says not to go to a GP with a dental abscess, because a GP cannot give dental treatment¹. NICE's guidance for clinicians keeps antibiotics for people who are unwell in themselves, show signs of severe or spreading infection, or are at high risk of complications, and even then points them on to urgent dental treatment³¹⁴. For everyone else, your practice or NHS 111 is the route to a dentist¹.

Can I go to A&E with a tooth infection?

Yes, if you have the signs the NHS lists: difficulty breathing, speaking or swallowing, swelling around the eye or in the neck, a swollen or painful eye or a sudden change in your sight, a lot of swelling in your mouth, or a mouth that is hard to open¹². Do not drive yourself; ask someone to take you or call 999¹. Without those signs, the usual door is an urgent dental appointment through your practice or NHS 111, and if you are unsure, NHS 111 can tell you which¹⁵.

Is it safe to wait until Monday?

This page cannot answer that for your mouth, and the NHS pages it relies on give doors, not a waiting time to choose. If you think you have a dental abscess, the NHS says to ask for an urgent appointment or contact NHS 111 now, and urgent dental treatment should be offered within 24 hours or seven days depending on the symptoms¹¹⁵. If any sign from the A&E list appears over the weekend, go to A&E or call 999¹.