title: Root canal microbiota of dogs' teeth with periapical lesions induced by two different methods.
abstract: OBJECTIVE
  The microbial composition was investigated in root canals of dogs' teeth with periapical lesions induced by 2 different methods: open versus sealed canals.
  
  
  METHODS
  Teeth from Group I (n = 16) were left open for a week, then sealed with composite resin for 120 days. The teeth from Group II (n = 16) were left open for the same period. Microbiological samples from the root canals were collected and processed by the anaerobic technique for identification and counting of microorganisms after establishment of periapical reactions.
  
  
  RESULTS
  Seventy-four cultivable isolates were recovered in sealed canals (Group I). Strict anaerobes accounted for 64.9% of all species isolated, and gram-negative microorganisms accounted for 55.4%. Microbial genera most frequently isolated were Prevotella, Fusobacterium, Peptostreptococcus, Streptococcus, Enterococcus, Clostridium, and Porphyromonas. Statistical analysis by Pearson chi-square or Fisher's test revealed positive association between sealed teeth and strict anaerobes (P < .05). In open canals (Group II), from a total of 58 cultivable isolates, 19% were strict anaerobes and 81% facultative anaerobes, with predominance of gram-positive species (75.8%). Genera most frequently isolated were Streptococcus, Propionibacterium, Staphylococcus, Neisseria, and Prevotella.
  
  
  CONCLUSIONS
  Strict anaerobes were most frequently found in sealed teeth rather than in the teeth with canals left exposed to the oral cavity for 4 months. Therefore, the method that induced periapical inflammatory lesions by intentional oral exposure, followed by tooth sealing, produced root canal microbiota similar to the same found in humans.
authors.affiliation: Department of Restorative Dentistry, Endodontic Area, Bauru Dental School, University of São Paulo, São Paulo, Brazil.
authors.forename: Flaviana Bombarda de Andrade
authors.initials: FB
authors.lastname: Ferreira
authors.forename: Helena Rosa
authors.initials: HR
authors.lastname: Campos Rabang
authors.forename: Ericka Tavares
authors.initials: ET
authors.lastname: Pinheiro
authors.forename: Cícero Romão
authors.initials: CR
authors.lastname: Gadê-Neto
authors.forename: Alexandre Augusto
authors.initials: AA
authors.lastname: Zaia
authors.forename: Caio Cezar Randi
authors.initials: CC
authors.lastname: Ferraz
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: de Souza-Filho
authors.forename: Brenda Paula Figueiredo de Almeida
authors.initials: BP
authors.lastname: Gomes
mesh_terms: D000818:Animals; D001421:Bacteria, Anaerobic / Q000254:growth & development; D001431:Bacteriological Techniques; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology*; D004285:Dogs; D005260:Female; D006090:Gram-Negative Bacteria / Q000254:growth & development; D006092:Gram-Negative Facultatively Anaerobic Rods / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000254:growth & development; D023421:Models, Animal; D010485:Periapical Periodontitis / Q000382:microbiology*