A patient presents with a draining sinus tract (fistula) associated with tooth #9 (maxillary left central incisor). What is the most appropriate treatment?

A draining sinus tract (fistula/parulis) indicates a chronic apical abscess with pulp necrosis as the underlying cause. The sinus tract provides drainage for the suppurative infection. Treatment must address the source of infection: root canal treatment (nonsurgical endodontic therapy) removes the infected pulp and bacteria from the canal system, allowing the periapical lesion and sinus tract to heal. Incision and drainage alone does not address the source of infection. Antibiotics are adjunctive and cannot penetrate the avascular necrotic pulp. Extraction is indicated only if the tooth is non-restorable. The sinus tract typically closes within 1-2 weeks after successful root canal treatment.