title: Occurrence of Prevotella intermedia and Prevotella nigrescens in relation to gingivitis and gingival health.
abstract: OBJECTIVE
  The occurrence of Prevotella intermedia (Pi) and Prevotella nigrescens (Pn) in relation to natural gingivitis, gingival health and 14-day experimental gingivitis was investigated in 25 non-dental students.
  
  
  METHODS
  Samples were taken from the dorsum of the tongue, the tonsils (or tonsillar area), and the supra- and subgingival plaque.
  
  
  RESULTS
  The microbiological results show that 73% of the samples were positive for the bacterial species presumed to be Pi and/or Pn. In natural gingivitis, gingival health and in experimental gingivitis 25, 23 and 25 subjects were found to be positive for Pi and/or Pn, respectively. The results of the 889 isolates that were successfully purified and differentiated, show that almost all subjects were colonized with Pn whereas approximately half of the study population harboured Pi. These 2 species were isolated from both dental plaque and mucosal sites and were found to colonize the oral cavity simultaneously.
  
  
  CONCLUSIONS
  In natural gingivitis, at the start and after 14 days of experimental gingivitis, Pn was the predominant micro-organism.
authors.affiliation: Department of Periodontology, Academic Centre for Dentistry Amsterdam, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: Lie
authors.forename: G A
authors.initials: GA
authors.lastname: van der Weijden
authors.forename: M F
authors.initials: MF
authors.lastname: Timmerman
authors.forename: B G
authors.initials: BG
authors.lastname: Loos
authors.forename: T J
authors.initials: TJ
authors.lastname: van Steenbergen
authors.forename: U
authors.initials: U
authors.lastname: van der Velden
mesh_terms: D000293:Adolescent; D000328:Adult; D015373:Bacterial Typing Techniques; D015169:Colony Count, Microbial; D003773:Dental Plaque / Q000382:microbiology; D005881:Gingiva / Q000382:microbiology; D005891:Gingivitis / Q000382:microbiology*; D006801:Humans; D009061:Mouth Mucosa / Q000382:microbiology; D018720:Prevotella / Q000302:isolation & purification*; D018713:Prevotella intermedia / Q000302:isolation & purification