title: Biofilm on the apical region of roots in primary teeth with vital and necrotic pulps with or without radiographically evident apical pathosis.
abstract: OBJECTIVE
  To evaluate, by scanning electron microscopy (SEM), the presence of biofilms on the external surfaces of the apical third of roots of human primary teeth with vital or necrotic pulps with and without radiographically evident periradicular pathosis.
  
  
  METHODS
  Eighteen teeth were selected: group I - normal pulp (n = 5), group II - pulp necrosis without radiographic evidence of periapical pathosis (n = 7) and group III - pulp necrosis with well-defined radiographic periapical pathosis (n = 6). After extraction, the teeth were washed with saline and immersed in 0.03 g mL(-1) trypsin solution for 20 min. The teeth were then washed in sodium cacodilate buffer and stored in receptacles containing modified Karnovsky solution. The teeth were sectioned, dehydrated in an ethanol series, critical-point dried with CO(2), sputter coated with gold and the external root surface in the apical third examined by SEM.
  
  
  RESULTS
  In the teeth of groups I and II, the apical root surfaces were covered by collagen fibres, with no evidence of bacteria (100%). In the teeth of group III, the root apices had no collagen fibres but revealed resorptive areas containing microorganisms (cocci, bacilli, filaments and spirochetes) in all cases (100%).
  
  
  CONCLUSIONS
  Microorganisms organized as biofilms on the external root surface (extraradicular infection) were detected in primary teeth with pulp necrosis and radiographically visible periapical pathosis.
authors.affiliation: Department of Paediatric, Preventive and Community Dentistry, School of Dentistry of Ribeirão Preto, Brazil.
authors.forename: C T
authors.initials: CT
authors.lastname: Rocha
authors.forename: M A
authors.initials: MA
authors.lastname: Rossi
authors.forename: M R
authors.initials: MR
authors.lastname: Leonardo
authors.forename: L B
authors.initials: LB
authors.lastname: Rocha
authors.forename: P
authors.initials: P
authors.lastname: Nelson-Filho
authors.forename: L A B
authors.initials: LA
authors.lastname: Silva
mesh_terms: D018441:Biofilms; D003782:Dental Pulp / Q000648:ultrastructure; D003790:Dental Pulp Necrosis / Q000382:microbiology*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010485:Periapical Periodontitis / Q000382:microbiology*; D010486:Periapical Tissue / Q000648:ultrastructure; D019227:Tooth Apex / Q000382:microbiology* / Q000648:ultrastructure; D014094:Tooth, Deciduous / Q000382:microbiology*