Persistent extraradicular infection in root-filled asymptomatic human tooth: scanning electron microscopic analysis and microbial investigation after apical microsurgery

J Endod. 2011 Dec;37(12):1696-700. doi: 10.1016/j.joen.2011.09.018.


Introduction: Procedural accidents have a negative effect on healing and might contribute to the persistence of infections in inaccessible apical areas, requiring surgical intervention. This report describes a case of persistent apical periodontitis of a lower left first molar associated with the sinus tract and a periapical lesion that required nonsurgical endodontic retreatment and apical surgery for resolution.

Methods: The tooth had received endodontic treatment 3 years ago and had to be retreated using the crown-down technique with chemical auxiliary substance (2% chlorhexidine gel), foramen patency, and enlargement and was filled in a single appointment. The occlusal access cavity was immediately restored with composite resin. After 1 month, it could be observed that the sinus tract persisted and, radiographically, the lesion remained unaltered. Therefore, endodontic microsurgery was indicated. Apical microsurgery was performed under magnification with the use of a dental operating microscope including apicectomy, root end with ultrasound, and sealing with mineral trioxide aggregate. A microbiological sample was collected from the apical lesion. The resected distal root apex was observed by scanning electron microscopy.

Results: The following species were detected: Actinomyces naeslundii and Actinomyces meyeri, Propionibacterium propionicum, Clostridium botullinum, Parvimonas micra, and Bacteroides ureolyticus; scanning electron microscopic analysis revealed bacterial biofilm surrounding the apical foramen and external radicular surface. Gutta-percha overfilling at the apex because of a zip caused during initial endodontic treatment could be observed. A 6-month follow-up showed apparent radiographic periapical healing, which progressed after 24 months.

Conclusion: Gram-positive anaerobic bacteria and extraradicular biofilm seem to participate in the maintenance of persistent periapical pathology, and endodontic retreatment followed by periapical microsurgery proved to be a successful alternative in the resolution of persistent extraradicular infections.

Publication types

  • Case Reports

MeSH terms

  • Actinomyces / isolation & purification
  • Adult
  • Aluminum Compounds / therapeutic use
  • Apicoectomy / methods*
  • Asymptomatic Diseases
  • Bacteroides / isolation & purification
  • Biofilms*
  • Calcium Compounds / therapeutic use
  • Clostridium botulinum / isolation & purification
  • Dental Fistula / therapy
  • Drug Combinations
  • Female
  • Follow-Up Studies
  • Gram-Positive Bacteria / isolation & purification
  • Humans
  • Microscopy, Electron, Scanning
  • Microsurgery / methods
  • Oxides / therapeutic use
  • Peptostreptococcus / isolation & purification
  • Periapical Periodontitis / microbiology*
  • Periapical Periodontitis / surgery
  • Piezosurgery / methods
  • Propionibacterium / isolation & purification
  • Retreatment
  • Retrograde Obturation / methods
  • Root Canal Filling Materials / therapeutic use
  • Root Canal Preparation / methods
  • Silicates / therapeutic use
  • Tooth Apex / microbiology
  • Tooth Apex / pathology
  • Tooth, Nonvital / therapy*


  • Aluminum Compounds
  • Calcium Compounds
  • Drug Combinations
  • Oxides
  • Root Canal Filling Materials
  • Silicates
  • mineral trioxide aggregate