title: Dentinal tubule infection as the cause of recurrent disease and late endodontic treatment failure: a case report.
abstract: BACKGROUND
  This article describes a case of recurrent post-treatment apical periodontitis and late failure after endodontic retreatment performed in a single visit.
  
  
  METHODS
  The patient presented with a tooth exhibiting inadequate endodontic treatment and a large periradicular lesion that extended laterally to the root. Retreatment was performed in a single visit and involved chemomechanical preparation using 5.25% NaOCl as the irrigant and root canal obturation by Schilder's vertical compaction technique. A large lateral canal was radiographically revealed after obturation. After 2 years, the lesion was no longer radiographically discernible, a condition that was confirmed 9 years after retreatment procedures. Nonetheless, after 12 years, radiographs revealed recurrent disease. Apical surgery was performed, and the root apex, including the area of the large lateral canal, was resected with care to maintain the lesion attached to it. The biopsy specimen was subjected to histopathologic and histobacteriologic analyses.
  
  
  RESULTS
  Longitudinal sections of the apical root specimen revealed a heavy dentinal tubule infection surrounding the area of the lateral canal. Bacteria were not found in any other area of the specimen. No other possible reason for the inflammatory periradicular lesion, such as root fracture, coronal leakage, or foreign-body reaction, was evident.
  
  
  CONCLUSIONS
  A persistent intraradicular infection caused by bacteria located within dentinal tubules is the most reasonable explanation for resurgence of the apical periodontitis lesion. This case report stresses the importance of attaining proper disinfection of the root canal system for a predictable long-term outcome of the treatment.
authors.affiliation: Brazilian Association of Dentistry, Juiz de Fora, Minas Gerais, Brazil.
authors.forename: Adalberto R
authors.initials: AR
authors.lastname: Vieira
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
authors.forename: Domenico
authors.initials: D
authors.lastname: Ricucci
authors.forename: Weber S P
authors.initials: WS
authors.lastname: Lopes
mesh_terms: D000328:Adult; D017607:Aluminum Compounds / Q000627:therapeutic use; D001047:Apicoectomy / Q000379:methods; D001706:Biopsy; D017610:Calcium Compounds / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000382:microbiology* / Q000648:ultrastructure; D003804:Dentin / Q000382:microbiology* / Q000648:ultrastructure; D004338:Drug Combinations; D005260:Female; D005500:Follow-Up Studies; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D010087:Oxides / Q000627:therapeutic use; D010485:Periapical Periodontitis / Q000382:microbiology*; D012008:Recurrence; D019233:Retreatment; D012184:Retrograde Obturation / Q000379:methods; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000379:methods; D012390:Root Canal Therapy / Q000379:methods*; D017640:Silicates / Q000627:therapeutic use; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D019227:Tooth Apex / Q000648:ultrastructure; D017211:Treatment Failure
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D017640:Silicates; C086631:mineral trioxide aggregate; D006171:Gutta-Percha; D012973:Sodium Hypochlorite