Dental abscess

Page last reviewed: 13/07/2011

A dental abscess is a collection of pus that can form in the teeth or gums as a result of a bacterial infection.

Bacteria are found in plaque (a byproduct of food, saliva and bacteria in the mouth). Plaque damages teeth and gums and can eventually infect the soft tissue inside a tooth or gums, forming an abscess.

There are two types of dental abscess:

  • periapical abscess (the most common type), when bacteria infect the inside of the tooth as a result of dental decay
  • periodontal abscess, when bacteria infect the gums

See Causes of dental abscess for more information about the two types.

Dental abscesses can be very painful and tender and can make a person feel unwell.


Without dental treatment, a dental abscess will get worse and may lead to the destruction of surrounding bone and other serious health problems.

Your GP will be able to prescribe appropriate treatment, but the only long-term solution for a dental abscess involves treatment from a dentist.


Page last reviewed: 13/07/2011


The main symptom of a dental abscess is pain in your affected tooth, which can be intense and throbbing. The pain usually comes on quite suddenly and gradually worsens over a few hours to a few days.

The pain may spread to your ear, lower jaw and neck on the same side as your affected tooth.

Other symptoms

Other symptoms of a dental abscess include:

  • tenderness of your tooth and surrounding area
  • sensitivity to very hot or cold food and drink
  • an unpleasant taste in your mouth
  • fever
  • a general feeling of being unwell
  • difficulty opening your mouth
  • difficulty swallowing (known as dysphagia)
  • disturbed sleep

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Page last reviewed: 13/07/2011

A dental abscess occurs when bacteria infect and spread inside a tooth or your gums.

The bacteria responsible for this are found in plaque, which also contains food particles left over from eating combined with saliva.

Periapical abscesses are much more common than periodontal abscesses.

Causes of a periapical abscess

When a periapical abscess occurs, plaque bacteria infect your tooth as a result of dental caries (tiny holes caused by tooth decay) that form in the hard outer layer of your tooth (the enamel).

Dental caries break down the enamel and the softer layer of tissue underneath (dentine) and eventually reach the centre of your tooth (pulp). This is known as pulpitis. The dental pulp in the middle of the tooth dies and the pulp chamber becomes infected.

The bacteria continue to infect the pulp until it reaches the bone that surrounds and supports your tooth (alveolar bone), where the periapical abscess forms.

Causes of a periodontal abscess

A periodontal abscess occurs when plaque bacteria affect your gums, causing gum disease (known as periodontitis).

Periodontitis causes inflammation (redness and swelling) in your gums, which can make the tissue that surrounds the root of your tooth separate from the base of your tooth. This separation creates a tiny gap known as a periodontal pocket, which can be very difficult to keep clean and allows bacteria to enter and spread. The periodontal abscess is formed by the build-up of bacteria in the periodontal pocket.

A periodontal abscess may also occur as a result of:

  • dental procedures that create accidental periodontal pockets
  • antibiotic use in untreated periodontitis, which can mask the beginnings of an abscess
  • damage to your gums, even if you do not have periodontitis

Page last reviewed: 13/07/2011

If you think you may have a dental abscess, you must see a dentist as soon as possible. You may need emergency dental treatment, which you can get access to through:

  • your usual registered dentist
  • the accident and emergency (A&E) department of your local general hospital

If you have a dental abscess and also have breathing or swallowing problems, go to the A&E department of your local hospital.

If you cannot get immediate treatment from a dentist, see your GP in the meantime. They will not be able to cure the abscess, but they can offer advice about caring for your tooth and managing the pain. They can also prescribe any appropriate medication.


Your GP may refer you for treatment in hospital if you have a dental abscess and:

  • you are feeling unwell with a high temperature, a rapid pulse rate or low blood pressure and rapid breathing
  • you are in severe pain despite using painkillers
  • you have a spreading facial infection
  • you have a weakened immune system (for example, because you are having chemotherapy)


Page last reviewed: 13/07/2011

The only way to cure a dental abscess is with dental treatment. Your dentist will treat your abscess using dental procedures and, in some cases, surgery.

Dental procedures

The first and most important step in treating a dental abscess is to cut out the abscess and drain away the pus that contains the infectious bacteria. These procedures are usually carried out under local anaesthetic, which means you will be awake but the affected area will be numb.

  • If you have a periapical abscess, the abscess will be removed using root canal treatment. Your dentist will drill into your dead tooth to release the pus and remove any damaged tissue from the centre (pulp). A root filling is then inserted into the space to prevent further infection, or the tooth can be extracted.
  • If you have a periodontal abscess, your dentist will drain it to release the pus and thoroughly clean out the periodontal pocket. Your dentist will then smooth out the surfaces of the root of your tooth by scaling and planing (filing) below your gum line to help your tooth heal and to prevent further infection.


If you have a periapical abscess and your infection recurs, you may need to be referred to an oral surgeon who can surgically remove any further diseased tissue.

If you have a periodontal abscess and your infection recurs, you may be referred to an oral surgeon who can reshape your gum tissue to permanently remove the periodontal pocket.

In some cases, a dental abscess infection can recur even after dental and surgical procedures. If this occurs or if your tooth is severely broken down, it may need to be removed altogether (extracted).

Treatment from your GP

If you have a dental abscess, you may not be able to see a dentist straight away. If this is the case, your GP can give you advice about painkillers and caring for your tooth and prescribe antibiotics if necessary.


A dental abscess can be very painful, but you can use over-the-counter painkillers from your local pharmacy to control the pain while you are waiting to receive dental treatment. Always read and follow the information on the packet about how much to take and how often, and do not exceed the maximum dose.

Painkillers cannot treat or cure a dental abscess, so they should not be used to delay dental treatment.

Follow the advice below to take painkillers safely:

  • Do not take ibuprofen if you are asthmatic or if you have (or have ever had) stomach ulcers.
  • Do not take more than one painkiller at the same time without first checking with your GP or other prescriber. This can be dangerous because many over-the-counter products contain similar painkillers and it is possible to overdose when combining products.
  • Ibuprofen and paracetamol are both available as liquid preparations for children.
  • Aspirin is not suitable for children under the age of 16.
  • If you are pregnant or breastfeeding, take paracetamol.
  • If your pain is particularly severe, your GP may prescribe a stronger painkiller, such as codeine phosphate. Alternatively, if you have been taking a low-dose codeine preparation, your GP may suggest increasing the dosage. However, do not increase the dose of any painkiller unless your GP advises you to.


Antibiotics for a dental abscess are used to prevent the spread of the infection and can be taken alongside painkillers.

Your GP may prescribe an antibiotic, such as amoxicillin or metronidazole, if:

  • your face is swollen (this may indicate that the infection is spreading to the surrounding areas)
  • you are showing signs of severe infection, such as a fever or swollen glands
  • you have a weakened immune system (for example, because you are having chemotherapy)
  • you have an increased risk of complications (for example, because you are diabetic)

Antibiotics should not be used to delay dental treatment.You must see a dentist if you have a dental abscess.

Caring for your tooth

There are several things you can do to limit pain and pressure on your dental abscess:

  • avoid very hot or cold food and drink
  • eat cool, soft foods using the opposite side of your mouth from the abscess
  • use a soft toothbrush and avoid flossing around the affected tooth

Page last reviewed: 13/07/2011

With appropriate dental treatment, a dental abscess can be treated quite easily. However, in rare cases, complications can occur. Most complications arise as a result of spreading bacterial infection when the abscess is left untreated.

Some of these complications are detailed below.

Dental cysts

If a dental abscess is left untreated, a fluid-filled cavity may develop at the bottom of the root of your tooth. This is known as a dental cyst. A cyst can become infected and need treatment with antibiotics. A dental cyst can be removed surgically under local anaesthetic (where the area is numbed).


Osteomyelitis is an infection of the bone. It is caused by the bacteria in a dental abscess spreading through your bloodstream. This condition can cause fever, nausea and severe pain in the affected bone, which can often be in the area surrounding a dental abscess.

However, as the infection is spread through your blood, it is possible for it to affect any bone in your body. Osteomyelitis can be treated by taking antibiotics orally or injecting them into a vein.

For more information, see : osteomyelitis.

Cavernous sinus thrombosis

This is a rare condition that can occur as a result of bacteria spreading from a dental abscess. It is estimated that 1 in 10 cases of cavernous sinus thrombosis begin as a dental infection.

The spread of bacteria causes a blood clot to form in a large vein at the base of your brain. In severe cases, this condition can be life threatening, but it can usually be treated with antibiotics or surgery to drain the sinus.

For more information, see cavernous sinus thrombosis.

Ludwig's angina

Ludwig's angina is a serious, potentially fatal infection of the floor of your mouth, which can occur if the bacteria in a dental abscess spread. It causes swelling and pain under your tongue and in your neck, and in severe cases it can obstruct your breathing.

Ludwig's angina can be treated with antibiotics, although an emergency procedure to open the airway (known as a tracheostomy) may be needed if breathing is restricted.

Maxillary sinusitis

This is an infection of the small, air-filled spaces behind your cheekbones, known as the maxillary sinuses. It can be caused by the spread of bacteria from a dental abscess. Maxillary sinusitis is not serious, but it can cause fever, pain and tenderness across your cheeks. Often it will clear up without treatment but, if necessary, antibiotics may be prescribed.

Content provided by NHS Choices and adapted for Ireland by the Health A-Z.

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