title: Persistence patterns of Porphyromonas gingivalis, Prevotella intermedia/nigrescens, and Actinobacillus actinomyetemcomitans after mechanical therapy of periodontal disease.
abstract: BACKGROUND
  The aim of this study was to determine the distribution patterns of Porphyromonas gingivalis, Prevotella intermedia/nigrescens, and Actinobacillus actinomycetemcomitans in periodontitis patients after standard mechanical periodontal therapy, and to determine factors increasing the odds to detect these target organisms in treated sites.
  
  
  METHODS
  Eight hundred fifty-two (852) separate subgingival microbial samples were taken from the mesial and distal aspects of every tooth in 17 patients. Target organisms were identified culturally.
  
  
  RESULTS
  The 3 microorganisms showed different persistence patterns: P. gingivalis was detected in a high percentage of subjects (59%), but in a low proportion of sites (5.4%). P. intermedia/nigrescens was detected in all subjects except one, and in 40.6% of the tested sites. Only 5 subjects were A. actinomycetemcomitans positive, but 2 of them showed a very high number of positive sites (44% and 75%, respectively). A highly significant relationship was found between a subject's tendency to bleed upon sampling and the number of P. intermedia/nigrescens-positive sites. A significant portion of the variation in frequency of persisting P. gingivalis could be explained by the frequency of persisting pockets deeper than 4 mm. No similar relationship could be established between clinical parameters and A. actinomycetemcomitans. On a site level, the odds of detecting P. gingivalis increased by a factor of 2.47 (P= 0.0001) for every millimeter of residual probing depth; the odds of detecting P. intermedia/nigrescens increased by a factor of 1.84 (P= 0.0001).
  
  
  CONCLUSIONS
  If, after standard mechanical periodontal therapy, a large number of sites continue to bleed, one may expect an increased number of sites positive for P. intermedia/ nigrescens. If many deep pockets persist, a greater number of P. gingivalis-positive sites can be expected.
authors.affiliation: School of Dental Medicine, Department of Periodontology and Fixed Prosthodontics, University of Bern, Switzerland. andrea.mombelli@medecine.unige.ch
authors.forename: A
authors.initials: A
authors.lastname: Mombelli
authors.forename: B
authors.initials: B
authors.lastname: Schmid
authors.forename: A
authors.initials: A
authors.lastname: Rutar
authors.forename: N P
authors.initials: NP
authors.lastname: Lang
mesh_terms: D000328:Adult; D000368:Aged; D016976:Aggregatibacter actinomycetemcomitans / Q000254:growth & development*; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D002710:Chlorhexidine / Q000627:therapeutic use; D015169:Colony Count, Microbial; D012534:Dental Scaling; D005260:Female; D005500:Follow-Up Studies; D005884:Gingival Hemorrhage / Q000382:microbiology / Q000628:therapy; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010510:Periodontal Diseases / Q000382:microbiology / Q000628:therapy*; D010514:Periodontal Pocket / Q000382:microbiology / Q000601:surgery / Q000628:therapy; D016966:Porphyromonas gingivalis / Q000254:growth & development*; D018720:Prevotella / Q000254:growth & development*; D018713:Prevotella intermedia / Q000254:growth & development*; D016745:Root Planing; D013357:Subgingival Curettage
chemical_list: D000891:Anti-Infective Agents, Local; D002710:Chlorhexidine