A tooth abscess is a pocket of pus that's caused by a bacterial infection. The abscess can occur at different regions of the tooth for different reasons. A periapical (per-e-AP-ih-kul) abscess occurs at the tip of the root, whereas a periodontal (per-e-o-DON-tul) abscess occurs in the gums next to a tooth root. The information here refers specifically to periapical abscesses.
A periapical tooth abscess usually occurs as a result of an untreated dental cavity, an injury or prior dental work.
Dentists will treat a tooth abscess by draining it and getting rid of the infection. They may be able to save your tooth with a root canal treatment, but in some cases the tooth may need to be pulled. Leaving a tooth abscess untreated can lead to serious, even life-threatening, complications.