Abscess, dental

A pus-filled sac in the tissue around the root of a tooth. An abscess may occur when bacteria invade the pulp (the tissues in the central cavity of a tooth) as a result of dental caries, which destroys the tooth’s enamel and dentine, allowing bacteria to reach the pulp. Bacteria can also gain access to the pulp when a tooth is injured. The infection in the pulp then spreads into the surrounding tissue to form an abscess. Abscesses can also result from periodontal disease, in which bacteria accumulate in pockets that form between the teeth and gums. The affected tooth aches or throbs, and biting or chewing is usually extremely painful. The gum around the tooth is tender and may be red and swollen. An untreated abscess eventually erodes a sinus (channel) through the jawbone to the gum surface, where it forms a swelling known as a gumboil. As the abscess spreads, the glands in the neck and the side of the face may become swollen, and fever may develop. Treatment may consist of draining the abscess, followed by root-canal treatment of the affected tooth, but in some cases extraction of the tooth is necessary. Antibiotics are prescribed if the infection has spread beyond the tooth. An abscess in a periodontal pocket can usually be treated by the dentist scraping away infected material.