Encyclopedia / D / Dental Abscesses

Dental Abscesses


An abscess is a localized collection of pus in a cavity formed by the disintegration of tissue.


Abscesses are usually caused by specific microorganisms that invade the tissues, often by way of small wounds or breaks in the skin. An abscess is a natural defense mechanism in which the body attempts to localize an infection and "wall off" the microorganisms so that they cannot spread throughout the body.

There are at least three types of dental abscesses that resemble each other. It is their point of origin that differentiates them.

A gum or gingival abscess is the result of injury to, or infection of, the surface of the gum tissue.

If an infection moves deep into gum pockets, drainage of pus is blocked and a periodontal abscess results.

A periapical abscess refers to a tooth in which the pulp is infected, usually secondary to tooth decay.


An abscess may occur when bacteria invades the dental pulp (the nerves and blood vessels that fill the central cavity of the tooth), causing the pulp to die. This most commonly happens as a result of dental caries, which destroy the tooth's enamel and dentin, allowing bacteria to reach the pulp. Bacteria can also gain access to the pulp when a tooth is injured.

Failure to treat an infected dental nerve usually leads to breakdown of the bone around the root with the formation of an abscess or cavity filled with pus.

The abscess is called acute or chronic, depending on how rapidly it forms and how effectively the body defends itself.

An acute abscess is characterized by pain, swelling, and fever.

A chronic abscess may be painless, with the patient completely unaware of its presence even as it continues to grow inside the jawbone. Or the area of infection may be walled off by a fibrous sac, forming a granuloma, which contains non-infectious (sterile) tissue but not pus.

Most of the pathological lesions and tips of roots are granulomas, but it is common practice to refer to all such conditions as abscesses. Since granulomas are usually painless and very slow-growing, they are discovered only by means of dental x-ray examinations. Unless the whole tooth is badly decayed, the tooth can be saved by root canal therapy.


Pain is gnawing and continuous. The involved tooth is painful when percussed (tapped), and often the teeth cannot close without added discomfort. Hot foods may increase the pain.

If treatment is delayed, the infection may spread through adjacent tissues, causing cellulitis, varying degrees of facial edema, and fever. The infection may spread to osseous (bony) tissues or into the soft tissues of the floor of the mouth.

Local swelling and gingival fistulas may develop opposite the apex of the tooth, especially with deciduous (temporary) teeth. Drainage into the mouth causes a bitter taste. Abscesses from lower molars may drain at the angle of the jaw.

A chronic periapical (at or around the apex of a root of a tooth) abscess usually presents few clinical signs, since it is essentially a circumscribed area of mild infection that spreads slowly.


It is important to determine which type of abscess is present so that the appropriate treatment may be rendered. In all three types of abscesses, the pus must be drained. Antibiotics may be prescribed if systemic symptoms such as fever and swelling in the lymph glands are present. (Mouth infections often affect the lymph glands in the neck region.) Deep cleaning will be undertaken for gum pocket (periodontal) abscesses.

If too much bone has been lost and the tooth is too loose, it may have to be extracted. In the case of a periapical abscess, root canal therapy or tooth extraction is indicated.

As diabetics are prone to the spread of infection, abscesses should be brought to the attention of their dentist so that prompt treatment may be begun.

Generally, an analgesic (pain-reliever) such as aspirin or acetaminophen alone or with codeine is needed. Bed rest, a soft diet, and fluids may be necessary.

Failure to treat an abscess can lead to serious infection as the pus spreads. Fever and malaise intensify when the infection penetrates the bone marrow of the jaw, producing osteomyelitis.

Prompt antibiotic therapy and surgical intervention in more extreme cases are usually successful in limiting the abscess or osteomyelitis, although often not before extensive and permanent damage has been done.


How serious is the condition?

Has any permanent damage been done?

If the nerve has been damaged, does a root canal always need to be done?

What type of treatment do you recommend?

For any surgical procedures or treatment for the bone, should a specialist be consulted?

Will you be prescribing any medication? What are the side effects?