title: Human teeth with periapical pathosis after overinstrumentation and overfilling of the root canals: a scanning electron microscopic study.
abstract: OBJECTIVE
  The aim of this study was to determine whether overinstrumentation followed by immediate overfilling could be a potential risk in the treatment of infected root canals.
  
  
  METHODS
  Thirty-five human teeth with infected root canals were overinstrumented and overfilled approximately 45 min after their extraction. The experimental teeth were enlarged up to size 40 and the overinstrumentation and overfilling were checked with the aid of a magnifying glass. The specimens were fixed in glutaraldehyde plus sodium cacodylate solution and prepared for scanning electron microscope examination.
  
  
  RESULTS
  Bacteria were detected on the flute of the files and mostly at the root apices around the main foramen, remaining firmly attached to resorptive lacunae despite the fact that the apices had undergone great changes, including fracture or zipping. A control group consisting of 10 human teeth root canals containing vital pulps were also overinstrumented and overfilled. No bacteria were detected on the flutes of the files, at the apices or on the extruded master cone overfilling these samples.
  
  
  CONCLUSIONS
  The high percentage of bacteria adhering to the resorptive lacunae or in the flutes of files used in overinstrumented human teeth with infected root canals carry a potential risk for postoperative pain, clinical discomfort and flare-ups. The hazards observed in these circumstances do not support the one-visit treatment of teeth having acute or chronic periapical abscesses.
authors.affiliation: Faculty of Dentistry, Department of Restorative Dentistry, University of Concepción, Chile.
authors.forename: J H
authors.initials: JH
authors.lastname: Gutiérrez
authors.forename: C
authors.initials: C
authors.lastname: Brizuela
authors.forename: E
authors.initials: E
authors.lastname: Villota
mesh_terms: D001419:Bacteria / Q000302:isolation & purification; D003786:Dental Pulp Cavity / Q000382:microbiology*; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000150:complications; D006171:Gutta-Percha; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010482:Periapical Abscess / Q000209:etiology / Q000382:microbiology / Q000628:therapy*; D012389:Root Canal Obturation / Q000009:adverse effects / Q000379:methods*; D018915:Root Canal Preparation / Q000009:adverse effects / Q000379:methods*; D019227:Tooth Apex / Q000293:injuries / Q000382:microbiology / Q000648:ultrastructure; D014082:Tooth Fractures / Q000209:etiology
chemical_list: D006171:Gutta-Percha