What is the periapical diagnosis for a tooth with a draining sinus tract (fistula)?

According to the American Association of Endodontists (AAE) diagnostic terminology, a chronic apical abscess (also called 'localized apical periodontitis with sinus tract' in newer terminology) is characterized by gradual onset, little or no pain, and an intermittent discharge of pus through a sinus tract. The sinus tract (fistula) is the hallmark feature. Radiographically, there is typically an apical radiolucency. A symptomatic apical abscess is characterized by rapid onset, intense pain, swelling, and no sinus tract. Treatment is root canal therapy to eliminate the source of infection.