title: Coronal leakage of mixed anaerobic bacteria after obturation and post space preparation.
abstract: OBJECTIVE
  The purpose of this study was to assess bacterial leakage of a mixed anaerobic community of organisms in obturated canals after post space preparation.
  
  
  METHODS
  A mixed microbial community of strict anaerobic organisms (F. nucleatum, P. micros and C. rectus) was developed. With the use of an in vitro model system, coronal leakage was assessed in 40 anterior teeth after obturation and post space preparation. The specific leakage time in days for each organism to penetrate through the obturating material was determined. In addition, colonization of the apical canal space was assessed by scanning electron microscope after longitudinal splitting of randomly selected specimens.
  
  
  RESULTS
  Eighty percent of the teeth demonstrated coronal leakage of F. nucleatum and C. rectus by the 90 day interval. Bacterial penetration occurred from 48 days to 84 days. Scanning electron microscope examination showed a heterogeneous biofilm of coccal and bacillary species colonizing the apical portion of the canal wall.
  
  
  CONCLUSIONS
  This study demonstrated that coronal leakage phenomena do occur after loss of coronal seals. The model system developed using mixed, anaerobic bacterial cultures is more clinically relevant and may be used to assess bacterial penetration through gutta percha obturation.
authors.affiliation: Department of Endodontics, University of Iowa, Iowa City, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Barrieshi
authors.forename: R E
authors.initials: RE
authors.lastname: Walton
authors.forename: W T
authors.initials: WT
authors.lastname: Johnson
authors.forename: D R
authors.initials: DR
authors.lastname: Drake
mesh_terms: D001421:Bacteria, Anaerobic / Q000254:growth & development / Q000502:physiology*; D018441:Biofilms; D002167:Campylobacter / Q000254:growth & development / Q000502:physiology; D015169:Colony Count, Microbial; D003763:Dental Leakage / Q000382:microbiology* / Q000473:pathology; D003786:Dental Pulp Cavity / Q000382:microbiology / Q000648:ultrastructure; D016967:Fusobacterium nucleatum / Q000254:growth & development / Q000502:physiology; D006171:Gutta-Percha; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010462:Peptostreptococcus / Q000254:growth & development / Q000502:physiology; D011176:Post and Core Technique; D012387:Root Canal Filling Materials; D012389:Root Canal Obturation; D013997:Time Factors; D019227:Tooth Apex / Q000382:microbiology / Q000648:ultrastructure; D019231:Tooth Preparation, Prosthodontic
chemical_list: D012387:Root Canal Filling Materials; D006171:Gutta-Percha