title: Prevalence and microbiological diversity of Archaea in peri-implantitis subjects by 16S ribosomal RNA clonal analysis.
abstract: OBJECTIVE
  This study evaluated the prevalence and the molecular diversity of Archaea in the subgingival biofilm samples of subjects with peri-implantitis.
  
  
  METHODS
  Fifty subjects were assigned into two groups: Control (n = 25), consisting of subjects with healthy implants; and Test (n = 25), consisting of subjects with peri-implantitis sites, as well as a healthy implant. In the Test group, subgingival biofilm samples were taken from the deepest sites of the diseased implant. In both groups, subgingival biofilm was collected from one site with a healthy implant and from one site with a periodontally healthy tooth. DNA was extracted and the 16S ribosomal RNA gene was amplified with universal primer pairs for Archaea. Amplified genes were cloned and sequenced, and the phylotypes were identified by comparison with known 16S ribosomal RNA sequences.
  
  
  RESULTS
  In the Control group, Archaea were detected in two and three sites of the implant and the tooth, respectively. In the Test group, Archaea were detected in 12, 4 and 2 sites of diseased implants, healthy implants and teeth, respectively. Diseased implants presented a significantly higher prevalence of Archaea in comparison with healthy implants and natural teeth, irrespective of group. Over 90% of the clone libraries were formed by Methanobrevibacter oralis, which was detected in both groups. Methanobacterium congelense/curvum was detected in four subjects from the Test group and in two subjects from the Control group.
  
  
  CONCLUSIONS
  Although M. oralis was the main species of Archaea associated with both healthy and diseased implant sites, the data indicated an increased prevalence of Archaea in peri-implantitis sites, and their role in pathogenesis should be further investigated.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Brazil. mfaveri@prof.ung.br
authors.forename: M
authors.initials: M
authors.lastname: Faveri
authors.forename: L F H
authors.initials: LF
authors.lastname: Gonçalves
authors.forename: M
authors.initials: M
authors.lastname: Feres
authors.forename: L C
authors.initials: LC
authors.lastname: Figueiredo
authors.forename: L A
authors.initials: LA
authors.lastname: Gouveia
authors.forename: J A
authors.initials: JA
authors.lastname: Shibli
authors.forename: M P A
authors.initials: MP
authors.lastname: Mayer
mesh_terms: D016301:Alveolar Bone Loss / Q000382:microbiology; D001105:Archaea / Q000145:classification* / Q000235:genetics; D018441:Biofilms; D002999:Clone Cells; D015921:Dental Implants / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology; D005260:Female; D005884:Gingival Hemorrhage / Q000382:microbiology; D006801:Humans; D008297:Male; D017014:Methanobacterium / Q000145:classification; D041581:Methanobrevibacter / Q000145:classification; D008875:Middle Aged; D057873:Peri-Implantitis / Q000382:microbiology*; D017622:Periodontal Attachment Loss / Q000382:microbiology; D010514:Periodontal Pocket / Q000382:microbiology; D010802:Phylogeny; D019642:RNA, Archaeal / Q000032:analysis*; D012336:RNA, Ribosomal, 16S / Q000032:analysis*; D014070:Tooth / Q000382:microbiology
chemical_list: D015921:Dental Implants; D019642:RNA, Archaeal; D012336:RNA, Ribosomal, 16S