title: Complex Apical Intraradicular Infection and Extraradicular Mineralized Biofilms as the Cause of Wet Canals and Treatment Failure: Report of 2 Cases.
abstract: This article describes 2 cases that showed persistent intracanal exudation (wet canal) even after several visits of antimicrobial endodontic treatment. Histologic and histobacteriologic investigation was conducted for determination of the cause. The 2 cases involved teeth with apical periodontitis lesions, which presented persistent exudation refractory to treatment after several visits. In case 1, it was not possible to achieve a dry canal, and surgery had to be performed. In case 2, attempts to dry the canal succeeded and the canal was filled, but follow-up examination showed an enlarged apical periodontitis lesion and extraction was performed. Biopsy specimens consisting of the root apex and apical periodontitis lesion for case 1 and the whole root for case 2 were subjected to histologic and histobacteriologic analyses. Both cases showed complex bacterial infection in the apical root, affecting both the intraradicular space and the outer root surface. Case 1 showed bacterial biofilms in ramifications, on untouched walls, and extending to the external root surface to form a thick and partially mineralized structure with high bacterial density. Different bacterial morphotypes were evidenced. Case 2 had a ledge on the apical canal wall created during instrumentation, which was filled with necrotic debris, filling material, and bacteria. The walls of the apical portion of the canal were covered by a bacterial biofilm, which was continuous with a thick extraradicular biofilm covering the cementum and dentin in resorptive defects. The extraradicular biofilm showed areas of mineralization and was dominated by filamentous bacteria. The 2 cases with wet canals and treatment failure were associated with complex persistent infection in the apical part of the root canal system extending to form thick and partially mineralized biofilm structures (calculus) on the outer apical root surface.
authors.affiliation: Private Practice, Cetraro, Italy. Electronic address: dricucci@libero.it.
authors.forename: Domenico
authors.initials: D
authors.lastname: Ricucci
authors.affiliation: Faculty of Dentistry, University of São Paulo, São Paulo, São Paulo, Brazil; Universitary Center Unichistus, Fortaleza, Ceará, Brazil.
authors.forename: George T M
authors.initials: GT
authors.lastname: Candeiro
authors.affiliation: Private Practice, Lecce, Italy.
authors.forename: Calogero
authors.initials: C
authors.lastname: Bugea
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
mesh_terms: D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000627:therapeutic use; D018441:Biofilms; D003739:Dental Cementum / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology; D003790:Dental Pulp Necrosis / Q000000981:diagnostic imaging / Q000382:microbiology / Q000473:pathology; D003804:Dentin / Q000382:microbiology; D006801:Humans; D008297:Male; D010482:Periapical Abscess / Q000382:microbiology / Q000473:pathology; D010485:Periapical Periodontitis / Q000382:microbiology* / Q000473:pathology*; D018915:Root Canal Preparation / Q000009:adverse effects*; D012390:Root Canal Therapy / Q000009:adverse effects* / Q000379:methods; D014092:Tooth Root / Q000382:microbiology; D017211:Treatment Failure
chemical_list: D000890:Anti-Infective Agents
keywords: Extraradicular infection; post-treatment apical periodontitis; treatment outcome; wet canal