A tooth abscess is a pocket of pus caused by a bacterial infection, either inside the tooth at the root tip (periapical) or in the gum beside it (periodontal). It usually follows untreated decay, a cracked tooth, or advanced gum disease. The classic signs are severe throbbing pain, swelling, sensitivity to heat and to biting, a bad taste, and sometimes fever. An abscess does not heal by itself, and antibiotics alone do not cure it: the infection must be physically drained, by a root canal, by draining the gum, or by extracting the tooth. Untreated, infection can spread into the jaw, neck, and bloodstream, which is why some symptoms warrant the emergency department rather than a dental appointment.
The two kinds
Periapical abscess. Infection at the tip of the root, inside the bone. Bacteria reach the pulp through a deep cavity, a crack, a failed filling, or trauma, kill the nerve, and spill out of the root tip into the surrounding bone. This is the most common type and the one most often needing a root canal.
Periodontal abscess. Infection in a gum pocket beside the tooth, usually in someone with existing gum disease, sometimes triggered by food debris forced into a deep pocket. The tooth itself may be perfectly healthy inside.
The distinction matters because treatment differs, and only an examination with an X-ray can tell them apart reliably.
Symptoms
- Severe, throbbing pain in the tooth, jaw, or ear on that side, often worse lying down
- Pain on biting or when the tooth is tapped
- Sensitivity to heat in particular, and to cold
- Swelling of the gum, cheek, or face
- A pimple-like bump on the gum that may ooze pus and taste foul (a sinus tract, which relieves pressure and often reduces the pain)
- Bad taste or bad breath that will not clear
- A loose tooth, or one that feels “high” when you bite
- Tender lymph nodes under the jaw or in the neck
- Fever and feeling generally unwell
One point catches people out: pain that suddenly stops is not good news. When the pulp dies, the nerve stops signalling, but the infection in the bone continues and will flare again, usually worse.
When it is an emergency
Most abscesses can wait for a same-day or next-day dental appointment. Some cannot. Go to the emergency department or call emergency services if you have:
- Swelling that spreads to the eye, under the jaw, or down the neck
- Difficulty swallowing, breathing, or opening your mouth
- Fever above 101°F (38.3°C) with facial swelling
- A rapidly growing swelling
- Confusion, severe fatigue, or a racing heartbeat alongside the infection
- Swelling in someone who is immunocompromised, pregnant, or diabetic
The danger is that infection tracks along tissue planes into the floor of the mouth and the neck, where it can obstruct the airway, or into the bloodstream, causing sepsis. These outcomes are uncommon, but they are the reason dentists treat facial swelling with urgency.
Treatment
The principle is always the same: drain the infection and remove its source.
Root canal. For a periapical abscess where the tooth is worth saving. The dentist opens the tooth, drains the pus through the canal, cleans and disinfects the root system, and seals it. Pain relief is usually dramatic and immediate. A crown normally follows. $700 to $1,800 for the root canal, plus $1,000 to $2,500 for the crown.
Incision and drainage. For a periodontal abscess or a collection in the gum, the dentist numbs the area and makes a small cut to release the pus, then cleans the pocket. $150 to $500.
Extraction. When the tooth is cracked below the gum, too decayed to restore, or the bone support is gone. The socket is cleaned as the tooth comes out. $150 to $700, more for a surgical extraction. Our guide to root canal vs extraction covers how that choice is made.
Antibiotics. Prescribed alongside drainage when there is swelling, fever, spreading infection, or a compromised immune system, usually amoxicillin or clindamycin for penicillin allergy. They are an adjunct, never the treatment. An abscess given antibiotics alone typically settles for a few weeks and then returns, often harder to treat, and repeat courses drive resistance.
Pain relief in the meantime: ibuprofen is more effective than acetaminophen for dental pain, and the two combined work better than either alone. A warm salt-water rinse several times a day helps a draining abscess. Do not apply heat to a facial swelling, do not try to burst a gum bump, and do not place aspirin against the tooth, which burns the tissue.
What happens if you leave it
An abscess does not resolve. It may become chronic, draining quietly through a sinus tract for months while the bone around the root is steadily destroyed, or it may flare acutely. The realistic outcomes of waiting are: a tooth that could have had a root canal now needing extraction; infection spreading into the jawbone (osteomyelitis) or the facial spaces (cellulitis, Ludwig’s angina); and, rarely, sepsis. Cost rises the same way, because a $900 root canal becomes a $400 extraction plus a $4,000 implant.
When to see a dentist
Contact a dentist the same day for any suspected abscess: severe or throbbing toothache, a gum bump that oozes, swelling of the gum or face, pain on biting with a bad taste, or a tooth that has become loose and painful. Treat it as urgent even if the pain has stopped, since that often signals a dead nerve rather than recovery. Go straight to an emergency department, not a dental office, for facial or neck swelling with fever, difficulty swallowing or breathing, a swollen eye, or a swelling that is growing quickly. Our guide to emergency dentists explains where to go outside office hours.
Frequently asked questions
Will a tooth abscess go away on its own?
No. The pus is walled off from the bloodstream, so the immune system cannot clear it and antibiotics cannot reach it properly. It must be drained. If the pain disappears, the nerve has usually died; the infection is still there.
Can antibiotics cure a tooth abscess?
No. Antibiotics reduce swelling and stop infection spreading, which is why they are often prescribed first, but they do not remove the source. Without a root canal, drainage, or extraction, the abscess returns.
How long can you leave a tooth abscess untreated?
It should be treated within days. There is no safe window: some abscesses smoulder for months, others spread to the face or neck within 24 to 48 hours. Facial swelling, fever, or difficulty swallowing means emergency care now.
What does a tooth abscess feel like?
Usually a severe, constant, throbbing pain in the tooth and jaw, worse when lying down and when biting, often with heat sensitivity. Many people also notice a bad taste, swelling, and tenderness in the neck glands.
Can a tooth abscess kill you?
It is rare in countries with accessible dental care, but yes, untreated dental infections can be fatal through airway obstruction or sepsis. That is precisely why facial swelling with fever or difficulty swallowing is treated as an emergency.
