Emergency dental conditions
Gum abscess: the two types and how each one is treated
A swollen, tender lump on the gum is a pocket of pus looking for a way out. Where it came from decides how we treat it, and it is rarely antibiotics alone.
Clinically reviewed by Dr Ibraheem Ijaz, Principal Dentist · GDC 301711 · Last reviewed April 2026
Periodontal or periapical: where the pus is coming from
An abscess is what the body does with an infection it cannot clear: it walls it off in a pocket of pus. In the mouth almost every abscess comes from one of two places, and they need different treatment.
A periapical abscess starts inside the tooth. Deep decay, a crack or an old injury lets bacteria into the nerve space. The nerve dies, the infection spreads out of the tip of the root into the bone, and the pus eventually tunnels through the bone and appears on the gum beside the tooth. The tooth itself is dead. The gum is only where the problem shows.
A periodontal abscess starts outside the tooth, in the gum. Gum disease creates a deep pocket between the gum and the root. If the opening of that pocket becomes blocked, by a fragment of food, a piece of tartar or simply swollen gum, the bacteria trapped inside multiply and pus builds up. The tooth is usually alive. People with a history of bleeding gums, loose teeth or a long gap since their last hygienist visit are most at risk, and diabetes makes it more likely still.
Two smaller cousins are worth knowing. A gingival abscess sits only in the gum edge and is often caused by something wedged there, classically a popcorn husk or a fish bone. A pericoronal abscess is a pericoronitis that has come to a head under the gum flap over a wisdom tooth.
What a gum abscess looks and feels like
- A raised, shiny, red or yellowish lump on the gum, usually near the root of one tooth. It may feel like a spot and may burst on its own.
- A throbbing ache, worse when lying down, that spreads to the jaw or ear.
- A tooth that feels high, so you hit it first when you close, and that hurts to tap.
- A tooth that has become loose over a few days.
- A foul taste or a salty discharge, especially if the lump has burst.
- Swelling of the face, a tender lump under the jaw, or feeling generally unwell and feverish.
One detail catches people out. The little pimple on the gum, which dentists call a sinus tract or gum boil, is a drainage vent. While it is draining, the pressure is off and the pain often eases or disappears. That is exactly the point at which people decide it has got better. It has not; the infection is still there and the vent can block again at any time. A gum boil that comes and goes for months is a dead tooth waiting to flare up.
Working out which type you have
At the £30 emergency examination, which includes X-rays, we separate the two types with a handful of tests. It takes a few minutes and it matters, because treating a periodontal abscess with a root canal, or a periapical abscess with gum cleaning, fixes nothing.
Where a sinus tract is present we sometimes slide a fine gutta-percha point into it and take an X-ray; the point runs straight to the source and shows us which root it belongs to.
| Test | Periapical abscess (dead tooth) | Periodontal abscess (gum pocket) |
|---|---|---|
| Cold test on the tooth | No response | Responds normally |
| Tapping the tooth | Very tender straight down | Tender, often more so sideways |
| Gum probe | Pocket depths normal | One deep pocket that bleeds and releases pus |
| X-ray | Dark area at the tip of the root | Bone loss down the side of the root |
| Where the swelling sits | Near the root tip, higher up | Nearer the gum margin |
| Tooth history | Deep filling, crown, crack or old knock | Gum disease, previous bleeding gums |
Draining the abscess and fixing the cause
Whatever the type, the first job is to let the pus out. Pus under pressure is what causes the throbbing, and no tablet reduces pressure. Then we deal with why it formed.
Periapical abscess. We numb the area and either open the tooth so the pus drains through the root canal, or make a small cut in the gum over the swelling (incision and drainage). The relief when the pressure comes off is usually immediate. The tooth then needs either root canal treatment to clean and seal the dead nerve space, or extraction. The emergency root canal stage, which drains, cleans and dresses the tooth, is from £200; completing the root canal is from £450, carried out by our associate Nik under a dental microscope. Extraction is £120–£260.
Periodontal abscess. We numb the gum, clean out the pocket with fine instruments and irrigate it with saline or chlorhexidine, removing the tartar or debris that blocked it. Draining through the pocket is usually enough; occasionally a small incision is needed. The tooth then needs a proper course of gum treatment to reduce the pocket, otherwise the abscess simply reforms. If the bone loss is severe and the tooth is very loose, extraction is sometimes the honest answer.
Prognosis is good in both cases when the cause is dealt with. A root-treated tooth that was abscessed heals in most cases, and the dark area on the X-ray fills back in with bone over the following year. A periodontal abscess on a tooth with modest bone loss settles well; one on a tooth that was already very loose has a poorer outlook. All fees are agreed in writing before treatment starts.
Easing a gum abscess tonight
- Paracetamol and ibuprofen, as directed on the packet. They can be taken together and work better together than either alone.
- Warm salt-water rinses, held over the area for a minute several times a day. If the boil has burst, this keeps it draining.
- Sleep with your head propped up on two pillows; lying flat raises the pressure and the throbbing.
- Keep brushing the tooth, gently. Leaving plaque on it makes things worse.
- Do not squeeze or lance the lump yourself, and do not put an aspirin or a painkiller tablet against the gum; it burns the tissue.
Ring 0114 288 2121 for a same-day slot. We are open 8am to 8pm every day, no registration is needed, and around eight in ten people who ring with an abscess are treated the day they call.
Why antibiotics alone rarely solve it
Antibiotics work by reaching bacteria through the bloodstream. A pocket of pus has no blood supply, and a dead tooth has none at all, so the drug cannot reach the bacteria that matter. A course may take the edge off the swelling for a week, and the abscess returns, often with bacteria that are harder to treat next time. UK guidance from SDCEP is clear that antibiotics are not a treatment for a dental abscess on their own; drainage and removal of the cause are. We prescribe them alongside drainage only when the infection is spreading into the face or neck or you have a fever, which is explained on our page about antibiotics for dental infection.
When it is more than a dental problem
Go to A&E or call 999 if swelling is closing your eye, spreading under your jaw and into your neck, crossing the midline of your face, or making it hard to swallow, open your mouth or breathe, or if you have a high temperature and feel very unwell. Infection in the floor of the mouth can threaten the airway within hours. The nearest A&E with a maxillofacial unit is the Northern General Hospital on Herries Road, about 20 minutes from Deepcar. Facial swelling that is not yet at that stage is covered in our guide to a swollen face.
Questions, answered
Common questions
Will a gum abscess go away on its own?
It may burst and feel better for a while, but the source, a dead tooth or a blocked gum pocket, is still there and it will come back. An abscess needs draining and the cause treating.
Can I just get antibiotics for a gum abscess?
Antibiotics alone do not cure an abscess because they cannot reach into pus or a dead tooth. We drain the abscess first and prescribe antibiotics only if the infection is spreading or you are unwell with it.
Should I pop a gum abscess?
No. Squeezing pushes bacteria deeper into the tissues and does not remove the cause. If it bursts by itself, rinse with warm salt water and still book to be seen.
How do you know if the abscess is from the tooth or the gum?
A cold test shows whether the tooth is alive, a gum probe shows whether there is a deep pocket, and the X-ray shows whether the infection sits at the root tip or down the side of the root.
Is a gum abscess dangerous?
Most are painful but contained. It becomes dangerous when swelling spreads to the eye, neck or floor of the mouth, or affects swallowing or breathing. Those need A&E, not a dental appointment.
Does an abscessed tooth have to be pulled?
Usually not. A periapical abscess can most often be treated with root canal treatment and the tooth kept. Extraction is chosen when the tooth is too broken down, too loose from bone loss, or you prefer it.
How much does abscess treatment cost?
The emergency examination with X-rays is £30. Draining and dressing a tooth as the first root canal stage is from £200, a full root canal from £450 and an extraction £120–£260. You get a written price before we start.
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