title: Recurrent apical periodontitis and late endodontic treatment failure related to coronal leakage: a case report.
abstract: BACKGROUND
  This article describes a case of late failure after endodontic retreatment as characterized by recurrent post-treatment apical periodontitis.
  
  
  METHODS
  At the time of the initial treatment, the patient presented with acute apical abscess associated with a tooth with pulp necrosis caused by trauma. Four years later, the tooth was retreated because of persistent disease. The follow-up examination 28 months after retreatment showed complete healing.
  
  
  RESULTS
  The patient returned 11 years and 7 months later for bleaching of the discolored tooth, and although the periodontal tissues were clinically and radiographically normal, a fracture line was observed on the mesial aspect of the pulp chamber. Extraction was indicated, but the patient only returned 5 years and 9 months later. Then a radiograph showed recurrent post-treatment apical periodontitis. The tooth was extracted, and histopathologic and histobacteriologic analyses revealed bacterial colonies along the fracture line and colonizing ramifications and accessory canals at the apical root canal system.
  
  
  CONCLUSIONS
  Coronal leakage can be regarded as the most reasonable explanation for resurgence of the disease. However, a predisposing overlapping condition in the form of root fracture conceivably favored the penetration of bacteria from saliva and plaque biofilm along the filled root canal.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Brazil. dricucci@libero.it
authors.forename: Domenico
authors.initials: D
authors.lastname: Ricucci
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
mesh_terms: D002648:Child; D003763:Dental Leakage / Q000150:complications*; D003790:Dental Pulp Necrosis / Q000628:therapy; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D007180:Incisor; D008437:Maxilla; D010482:Periapical Abscess / Q000628:therapy; D010485:Periapical Periodontitis / Q000209:etiology*; D012008:Recurrence; D019233:Retreatment; D012390:Root Canal Therapy; D014075:Tooth Discoloration / Q000209:etiology; D014081:Tooth Extraction; D014082:Tooth Fractures / Q000150:complications*; D017211:Treatment Failure