A dental abscess is a pocket of pus caused by a bacterial infection, usually at the tip of a tooth’s root or in the gum beside a tooth. It often causes throbbing pain, swelling and tenderness, and it does not clear up on its own: the source of the infection needs dental treatment. If you have swelling that is spreading, a fever, or any difficulty swallowing or breathing, treat it as a medical emergency and go to a hospital emergency department or call 000.
What causes a dental abscess?
An abscess forms when bacteria get into a part of the tooth or gum where the body can’t easily clear them. Pus builds up as the immune system fights the infection, and because it is trapped, pressure builds and causes pain.
The main types
- Periapical abscess. This starts inside the tooth. Deep decay, a crack or an old injury lets bacteria reach the pulp (the nerve and blood supply in the centre of the tooth). The pulp becomes infected and dies, and infection spreads out through the tip of the root into the surrounding bone.
- Periodontal abscess. This starts in the gum and supporting bone beside a tooth, usually in someone with existing gum disease where a deep pocket has formed between tooth and gum.
- Pericoronal infection. This affects the gum flap over a partly erupted tooth, most often a lower wisdom tooth. Food and bacteria get trapped underneath and the area becomes swollen and sore.
Common risk factors
- Untreated tooth decay
- Cracked or broken teeth, or large old fillings that have leaked
- Gum disease
- A previous knock to a tooth, sometimes years earlier
- Partly erupted wisdom teeth
- Conditions or medications that affect immunity, such as poorly controlled diabetes
Signs and symptoms of a dental abscess
Symptoms vary depending on the type and how far the infection has progressed. Common signs include:
- Persistent, throbbing toothache that may spread to the ear, jaw or neck
- Pain when biting or when the tooth is tapped
- Sensitivity to hot or cold, or pain that lingers after a hot drink
- Swelling of the gum, often with a small pimple-like bump that may discharge pus
- A bad taste or smell in the mouth
- Swelling of the cheek, jaw or under the chin
- Tender, swollen glands in the neck
- Feeling generally unwell or feverish
When the pain suddenly stops
Sometimes the pain eases suddenly. This can happen if the abscess bursts and drains, or if the nerve inside the tooth has died. It is tempting to think the problem has gone, but the infection usually remains and can flare up again. A tooth that has stopped hurting after a period of severe pain still needs to be checked.
Abscesses that cause few symptoms
Some chronic abscesses cause little or no pain and are found on an x-ray at a routine check-up, or show up as a recurring small bump on the gum. They still need treatment, because the infection can slowly damage bone and may become painful later.
Why a dental abscess can be serious
Most dental abscesses stay localised and are managed well with prompt dental treatment. However, infection in the mouth can occasionally spread into the tissues of the face and neck. Rarely, this can become life-threatening by affecting the airway or spreading into the bloodstream.
Seek emergency medical care straight away if you have
- Swelling that is spreading quickly, or swelling under the tongue or down into the neck
- Difficulty swallowing, breathing or opening your mouth
- Swelling around the eye, or the eye closing
- A high temperature, chills or feeling very unwell
- Confusion or extreme drowsiness
In these situations go to the nearest hospital emergency department or call 000. Do not wait for a dental appointment.
How a dentist treats a dental abscess
The aim of treatment is to drain the infection and remove its source. Antibiotics alone don’t cure an abscess, because they can’t reach the bacteria inside a dead tooth or a deep gum pocket well. The right approach depends on which tooth is affected, how much healthy tooth structure remains, and what you would prefer after discussing the options.
Assessment
Your dentist will ask about your symptoms and medical history, examine the area and usually take an x-ray to see the root tip and surrounding bone. Sometimes 3D imaging is helpful for complex cases.
Draining the infection
Relieving the pressure often brings substantial relief. This may be done by opening into the tooth, by a small incision in the gum, or by cleaning out a gum pocket. Local anaesthetic is used to keep you comfortable.
Root canal treatment
If the tooth can be saved, root canal therapy removes the infected pulp, cleans and disinfects the canals, and seals them. A back tooth often needs a crown afterwards because root-filled teeth can become brittle. Root canal treatment has a good success rate in general, but it is not always successful; some teeth need retreatment, and complex or curved canals may be referred to a specialist endodontist.
Extraction
If a tooth is badly broken down, cracked below the gum, or has lost too much bone support, removing it may be the most sensible option. Our page on tooth extractions explains what to expect. After an extraction, your dentist can talk with you about whether and how to replace the tooth, such as with a bridge, denture or implant, each of which has its own pros, cons and suitability criteria.
Gum treatment
For a periodontal abscess, the pocket is cleaned and drained, and the underlying gum disease needs ongoing management to reduce the chance of recurrence.
Antibiotics
Antibiotics may be prescribed when the infection is spreading, when you have a fever, or when you have a medical condition that increases your risk. They are not routinely needed for every abscess, and using them unnecessarily contributes to antibiotic resistance. They support treatment; they do not replace it.
What you can do before your appointment
- Take over-the-counter pain relief exactly as directed on the packet, and ask a pharmacist if you’re unsure what is suitable for you.
- Rinse gently with warm salty water (half a teaspoon of salt in a glass of warm water) a few times a day.
- Use a cold pack wrapped in a cloth on the outside of the face for short periods if it helps.
- Avoid chewing on the affected side and avoid very hot, cold or sugary food and drink.
- Don’t apply heat to a facial swelling, and don’t place aspirin directly on the gum, as it can burn the tissue.
- Don’t try to pop or squeeze a gum swelling yourself.
- Keep brushing and cleaning gently, including around the sore tooth.
Preventing a dental abscess
Most abscesses start with problems that can be picked up early. Brushing twice a day with fluoride toothpaste, cleaning between teeth daily, limiting sugary food and drinks, and having regular check-ups help catch decay and gum disease before infection develops. If you crack or chip a tooth, or a filling falls out, have it looked at even if it doesn’t hurt. Wearing a mouthguard for contact sports reduces the risk of injuries that can damage the pulp.
When to see a dentist
See a dentist promptly, ideally the same day or the next day, if you have a persistent toothache, pain on biting, a gum bump that discharges, a bad taste that won’t go away, or any facial swelling without the emergency warning signs listed above. North Ryde Dentistry offers emergency appointments on the same day where available, and calling before 10am gives you a better chance of a same-day visit. Our Macquarie Park practice is open Monday, Tuesday, Thursday and Friday 9:00am to 6:00pm and Saturday 8:30am to 4:00pm, and is closed Wednesday and Sunday. Outside these hours, if you have any of the serious symptoms above, go to a hospital emergency department.
Frequently asked questions
Can a dental abscess go away on its own?
No. The pain may settle if the abscess drains or the nerve dies, but the infection usually remains and can flare again or spread. The source of the infection needs to be treated by a dentist.
Will antibiotics fix a dental abscess?
Antibiotics alone don’t cure an abscess. They may be prescribed if the infection is spreading or you are unwell, but the tooth or gum still needs treatment such as drainage, root canal treatment or extraction.
Is a dental abscess an emergency?
It needs prompt dental care. It becomes a medical emergency if you have spreading swelling, difficulty swallowing or breathing, swelling near the eye or a high fever. In that case go to a hospital emergency department or call 000.
Can a tooth with an abscess be saved?
Often, yes. Root canal treatment can save many abscessed teeth if enough healthy tooth structure and bone support remain. If the tooth is too damaged, extraction may be recommended. Your dentist will explain the options after assessment.
How much does abscess treatment cost?
It depends on what is needed, such as drainage, root canal treatment, a crown afterwards or an extraction, and on which tooth is involved. Your dentist will give you a written estimate after assessment.
If you think you have an abscess, don’t wait for it to settle. Call North Ryde Dentistry on (02) 8090 1102 or book an appointment.
This article is general information only and is not a substitute for advice from your own dentist. Any treatment carries risks; your dentist will discuss whether it is suitable for you.
Related at North Ryde Dentistry: our North Ryde dental clinic