A throbbing tooth that keeps you awake, a swollen patch of gum or a bad taste that keeps coming back are all signs that an infection may have built up into an abscess. An abscess will not clear up by itself. The pain can fade for a while, but the bacteria stay, so the tooth needs a dentist to drain the infection and deal with its cause. If your face is swelling, you have a fever, or you are finding it hard to swallow or breathe, go to a hospital emergency department or call 000 now.
Swelling, fever or trouble swallowing means hospital, not a wait for an appointment
Most abscesses stay around one tooth and can be managed in the dental chair. A small number spread into the deeper spaces of the face and neck, and those can become dangerous within a day or two. Treat these as an emergency:
- swelling that is spreading across the cheek, under the jaw, down the neck or towards the eye
- fever, chills or feeling generally unwell
- difficulty swallowing, opening your mouth or breathing
- swelling under the tongue that lifts it upwards
The last of these can be a sign of Ludwig's angina, a spreading infection of the floor of the mouth that can block the airway. Hospital teams can secure the airway, drain the swelling and give antibiotics through a drip. They usually do not repair the tooth itself, so a dental visit still needs to follow once you are well.
An abscess is pus that has nowhere to go
When bacteria reach tissue that is normally free of infection, the body sends white blood cells to fight them. The dead cells, bacteria and fluid collect as pus. Inside a tooth or a tight gum pocket there is little room for that pus to escape, so pressure rises, and pressure on the surrounding nerves and bone is what makes an abscess throb.
Dentists usually describe two kinds, because they are treated differently.
At the root tip, starting inside the tooth
Bacteria get into the pulp, the soft core of the tooth that holds the nerve and blood supply, usually through deep decay, a crack or a leaking filling. Once the pulp dies, the infection seeps out through the end of the root into the jawbone. This is the more common type, and it is the one behind most severe, constant toothaches.
In the gum, beside a tooth that may still be alive
A gum (periodontal) abscess forms in a pocket between the tooth and gum, often in someone who already has gum disease. Food or plaque gets trapped deep in the pocket and the area becomes red, swollen and tender, and may ooze when pressed. The tooth itself can still react normally to cold. Our article on gum disease treatment explains how deep pockets are managed.
Pain that will not switch off is the main warning sign
An ordinary sensitive tooth twinges with cold and settles within a few seconds. Cold sensitivity on its own is often dentine sensitivity rather than infection. An abscess behaves differently. Common signs include:
- a constant, throbbing ache that may spread to the jaw, ear or temple on the same side
- pain that is worse lying down or wakes you at night
- pain from heat that lingers after the hot drink is gone
- tenderness when you bite on one particular tooth
- a small pimple on the gum near the sore tooth, which may leak a salty or foul-tasting fluid
- a bad taste or bad breath that brushing does not shift
- a tooth that has started to feel loose
The pimple on the gum is called a sinus tract or fistula. It means the pus has found its own way out. The pressure and pain often drop once this happens, which can be misleading. The infection is still there.
How bacteria get in
Deep decay is the most common route into the pulp. Early decay rarely hurts, so a cavity can grow for months before it reaches the nerve. Cracks are another way in, including hairline cracks around large old fillings that cannot be seen in a mirror. Fillings and crowns that have worn or leaked at their edges can let bacteria back in underneath.
A knock to a front tooth can damage its blood supply without breaking anything visible. The pulp may die quietly and become infected months or even years later, which is why a dentist will often want to recheck a tooth after an injury. Gum abscesses mostly come from established gum disease, and smokers and people with poorly controlled diabetes are at higher risk.
A tooth can feel tender for a few days after a deep filling or crown preparation. Pain that gets stronger rather than settling, or that starts to throb at night, is worth a call to your dentist.
What the dentist checks
Diagnosis is usually quick. Your dentist will ask how the pain started and what makes it worse, look for swelling or a sinus tract, and gently tap and test the teeth in the area. A tooth with a dead pulp usually does not respond to a cold test but is sore to tap. With a gum abscess, the tooth often responds normally while the gum beside it is tender.
An X-ray of the tooth then shows what is happening at the root. A longstanding infection often appears as a dark area of bone loss around the root tip. If several teeth are involved, or the picture is unclear, a panoramic or 3D X-ray may help.
Treatment removes the source, and antibiotics are not a substitute
Every abscess needs the infection drained and its cause dealt with. Depending on the tooth, that means one or more of the following.
Draining the abscess. Under local anaesthetic, the dentist may make a small opening in the gum or through the tooth to let the pus out. Relief from pressure is often quick.
Root canal treatment. The infected pulp is removed, the canals are cleaned and shaped, and the tooth is sealed. A systematic review found that about 86% to 93% of root-filled teeth were still in place 2 to 10 years later, and teeth that had a crown placed afterwards did better (Ng and colleagues, International Endodontic Journal, 2010). A crown is often advised for back teeth because they take heavy biting forces.
Treating a gum abscess. The pocket is cleaned out and drained, then the underlying gum disease is treated so the problem is less likely to return.
Removing the tooth. If the tooth is too broken down or the bone loss is too severe to repair predictably, extraction clears the infection. Your dentist will talk through options for replacing it later.
Antibiotics have a narrower role than many people expect. A Cochrane review notes that clinical guidelines recommend removing the source of infection as the first treatment, with antibiotics reserved for signs of spreading infection, such as diffuse swelling or swollen lymph nodes, or general illness such as fever (Cope and colleagues, Cochrane Database of Systematic Reviews, 2024). In the trials it reviewed, adding antibiotics to dental treatment made little or no clear difference to pain or swelling. Unnecessary antibiotics also add to antibiotic resistance. If you are given a course, the tooth still needs treatment once the swelling settles.
Typical market costs
Costs depend on which tooth is involved and what it needs. The ranges below are typical for private general practice in Sydney. They are general market figures, not Lumi Dental fees.
| Treatment | Typical market range |
|---|---|
| Root canal treatment | about $1,000 (front tooth) to $3,000 (molar) |
| Crown after root canal treatment | $1,500 to $2,500 |
| Simple extraction | $200 to $350 |
| Surgical extraction | $400 to $900 |
The examination and X-rays are charged separately. Health fund extras cover varies widely, and root canal treatment and crowns usually fall under major dental, which often has lower annual limits and a longer waiting period. Ask your fund what it will pay for the item numbers on your treatment plan.
Until you can be seen
These steps can make the wait easier, but none of them treats the infection.
- For pain, if they are safe for you, ibuprofen and paracetamol taken together have the strongest evidence for dental pain among common medicines (Moore and colleagues, Journal of the American Dental Association, 2018). Follow the directions on the pack and ask a pharmacist first if you have stomach, kidney, liver or heart problems, are pregnant, or take other medicines.
- Rinse gently with warm salt water a few times a day.
- A cold pack held against the outside of the cheek, wrapped in a cloth, may ease discomfort.
- Many people find an extra pillow at night makes the throbbing more bearable.
- Chew on the other side and avoid very hot or very cold food and drinks.
- Do not pierce or squeeze a gum swelling with a pin, needle or fingernail, which can push infection further into the tissues.
Aim to see a dentist within 24 hours, and sooner if any of the emergency signs above appear.
Feeling better is not the same as healing
Abscess pain often eases suddenly, either because the pus drains through the gum or because the nerve inside the tooth has completely died. The infection keeps going, slowly dissolving bone around the root, and it can flare again. The longer it is left, the more bone is lost and the less likely the tooth can be saved, so early treatment usually gives more options.
Lowering the chance of another abscess
Most abscesses begin with decay, a crack or gum disease that has gone unnoticed. Regular check-ups, at an interval your dentist or OHT suggests for your risk, give a chance to find these early, and bitewing X-rays can show decay between teeth before it reaches the nerve. Fillings that have chipped or feel rough are worth having checked, and a tooth that hurts when you bite and release may have a crack that a crown or onlay can protect.
At home, brush twice a day with fluoride toothpaste and clean between your teeth daily. If you have gum disease, regular professional cleans help keep pockets under control. For contact sport, a well-fitting mouthguard helps protect front teeth from the knocks that can damage the pulp.
If fear of the dentist is part of why a sore tooth has been left, you are far from alone, and our article on dental anxiety covers ways to make visits easier.
Questions we are often asked
How quickly do I need to be seen?
Within 24 hours if you can, and the same day if you have swelling, fever, trouble swallowing or pain that over-the-counter pain relief does not control. If breathing or swallowing is affected, go to a hospital emergency department.
Can I just take antibiotics?
Antibiotics do not remove the infected pulp or the pus inside a sealed pocket. Guidelines reserve them for spreading infection or general illness, and the tooth still needs draining, root canal treatment or extraction.
Will I lose the tooth?
Not necessarily. Many abscessed teeth can be kept with root canal treatment, especially when treated early. Extraction is considered when decay, a crack or bone loss has gone too far for a predictable repair.
Can an abscess be dangerous?
Rarely, an untreated dental infection spreads to the airway or bloodstream and becomes life threatening. That is why spreading swelling, fever or difficulty breathing or swallowing need urgent hospital care.
If you think you have an abscess
Lumi Dental offers emergency appointments. Our emergency dentist page explains how to be seen quickly, and after an examination you will usually receive a written treatment plan, often by email. If nerves are a concern, ask us about happy gas (relative analgesia) and other sedation options, including IV sedation. For check-ups that help catch problems early, see our current offers page for our practice at Melrose Central, Melrose Park.
This article is general information only and is not a substitute for an examination by a registered dental practitioner. If you are experiencing facial swelling, fever, or difficulty breathing or swallowing, attend a hospital emergency department or call 000.
