title: Comprehensive microbiological findings in peri-implantitis and periodontitis.
abstract: OBJECTIVE
  The microbial differences between peri-implantitis and periodontitis in the same subjects were examined using 16S rRNA gene clone library analysis and real-time polymerase chain reaction.
  
  
  METHODS
  Subgingival plaque samples were taken from the deepest pockets of peri-implantitis and periodontitis sites in six subjects. The prevalence of bacteria was analysed using a 16S rRNA gene clone library and real-time polymerase chain reaction.
  
  
  RESULTS
  A total of 333 different taxa were identified from 799 sequenced clones; 231 (69%) were uncultivated phylotypes, of which 75 were novel. The numbers of bacterial taxa identified at the sites of peri-implantitis and periodontitis were 192 and 148 respectively. The microbial composition of peri-implantitis was more diverse when compared with that of periodontitis. Fusobacterium spp. and Streptococcus spp. were predominant in both peri-implantitis and periodontitis, while bacteria such as Parvimonas micra were only detected in peri-implantitis. The prevalence of periodontopathic bacteria was not high, while quantitative evaluation revealed that, in most cases, prevalence was higher at peri-implantitis sites than at periodontitis sites.
  
  
  CONCLUSIONS
  The biofilm in peri-implantitis showed a more complex microbial composition when compared with periodontitis. Common periodontopathic bacteria showed low prevalence, and several bacteria were identified as candidate pathogens in peri-implantitis.
authors.affiliation: Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Koyanagi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Noriko
authors.initials: N
authors.lastname: Maruyama
authors.forename: Moriya
authors.initials: M
authors.lastname: Ohkuma
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Izumi
mesh_terms: D000368:Aged; D016301:Alveolar Bone Loss / Q000382:microbiology; D001419:Bacteria / Q000145:classification*; D001439:Bacteroides / Q000145:classification; D041963:Bacteroidetes / Q000145:classification; D018441:Biofilms; D003773:Dental Plaque / Q000382:microbiology; D005260:Female; D005673:Fusobacterium / Q000145:classification; D015723:Gene Library; D005884:Gingival Hemorrhage / Q000382:microbiology; D006094:Gram-Positive Bacteria / Q000145:classification; D006801:Humans; D008297:Male; D008875:Middle Aged; D010462:Peptostreptococcus / Q000145:classification; D057873:Peri-Implantitis / Q000382:microbiology*; D010514:Periodontal Pocket / Q000382:microbiology; D010518:Periodontitis / Q000382:microbiology*; D016966:Porphyromonas gingivalis / Q000145:classification; D020560:Proteobacteria / Q000145:classification; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D013291:Streptococcus / Q000145:classification; D048373:Treponema denticola / Q000145:classification
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S