Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Synonyms and keywords: root abscess, dental abscess
A tooth abscess is pus enclosed in the tissues of the jaw bone at the tip of an infected tooth. Usually the abscess originates from a bacterial infection that has accumulated in the soft pulp of the tooth. This is usually, but not always, associated with a dull, throbbing, excruciating ache.
There are two types of dental abscess.
- A periapical abscess starts in the dental pulp.
- A periodontal abscess begins in the supporting bone and tissue structures of the teeth.
A tooth abscess typically originates from dead pulp tissue.
- Tooth decay
- Cracked teeth
- Extensive periodontal disease
- A failed root canal treatment may also create a similar abscess
Natural History, Complications and Prognosis
An untreated severe tooth abscess may become large enough to perforate bone and extend into the soft tissue. From there it follows the path of least resistance and may spread either internally or externally. The path of the infection is influenced by such things as the location of the infected tooth and the thickness of the bone, muscle and fascia attachments.
External drainage may begin as a boil which bursts allowing pus drainage from the abscess, intraorally (usually through the gum) or extra orally. Chronic drainage will allow an epithelial lining to form in this communication to form a pus draining canal (fistula). Sometimes this type of drainage will immediately relieve some of the painful symptoms associated with the pressure.
Internal drainage is of more concern as growing infection makes space within the tissues surrounding the infection. Severe complications requiring immediate hospitalisation include Ludwig's angina, which is a combination of growing infection and cellulitis which closes the airway space causing suffocation in extreme cases. Also infection can spread down the tissue spaces to the mediastinum which has significant consequences on the vital organs such as the heart. Another complication, usually from upper teeth, is a risk of septicaemia (infection of the blood), from connecting into blood vessels. Brain abscess, while extremely rare, is also a possibility.
Depending on the severity of the infection, the sufferer may feel only mildly ill, or may in extreme cases require hospital care.
Common symptoms of an acute tooth abscess is a toothache or a persistent, throbbing pain at the site of the infection. Putting pressure or warmth on the tooth may induce extreme pain.
In some cases, a tooth abscess may perforate bone and start draining into the surrounding tissues creating local facial swelling. In some cases, the lymph glands in the neck will become swollen and tender in response to the infection.
One treatment for an abscessed tooth is to extract it, thereby removing the source of infection. However, in select cases a root filling or root canal therapy may be able to save the tooth by cleaning the source of infection in the pulp chamber and root canal system (for more information see Root canal therapy). Another possible treatment of an abscessed tooth is an invasive surgery through the cheek. The doctor will then remove the tooth, ridding the source of infection. Finally, the doctor will insert a tube through the cheek routing it the site of the tooth so any other pus may drain out through the tube in to either a Jackson-Pratt bulb or directly onto a surgical sponge.