title: [Distribution of periodontal pathogens in dental plaque samples from 7 to 12-years-old children of Changchun Ziqiang primary school].
abstract: OBJECTIVE
  To detect the presence of Porphyromonas gingivalis (Pg) and Actinobacillus actinomycetemcomitans (Aa) using polymerase chain reaction (PCR) in the oral plaque samples from children and investigate the relationship between bacteria and clinical parameters.
  
  
  METHODS
  A total of 151 children aged 7 to 12 years were selected from Changchun Ziqiang primary school. The supragingival plaque sample was collected from the mesiobuccal and labial surfaces of the right maxillary central incisor and the right maxillary first molar. Extracted DNA from plaque samples was used for PCR analysis. Intraoral examination, probing depth (PD) and bleeding on probing (BOP) were performed and recorded.
  
  
  RESULTS
  The detection rate for Pg was 27.6% and Aa 54.3% in supragingival plaque. The detection rates for Pg in molars were much higher than those in incisors (P < 0.01). The detection rate of Pg was positively related to BOP+ and PD. The detection rate for Pg increased gradually with aging, and the detection rate for Aa was highest in the group aged 11 to 12 and the detection rates for Pg and Aa were higher in the gingiva with BOP+ than that with BOP- (P < 0.05). The detection rates for Pg increased remarkably with BOP+ and especially when PD was greater than 4 mm.
  
  
  CONCLUSIONS
  Detection rates of putative periodontal pathogens from healthy children of 7 to 12 years of age were high. The detection rates for Pg in molars were much higher than those in incisors,and the presence of Pg and Aa in supragingival plaque was related to periodontal parameters.
authors.affiliation: Medical Center of Stomatology, Beijing Anzhen Hospotal Affiliated Hospital of Capital University of Medicine, Beijing 100029, China. nixueyan@hotmail.com
authors.forename: Xue-yan
authors.initials: XY
authors.lastname: Ni
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ida
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Suzuki
authors.forename: Ya-lin
authors.initials: YL
authors.lastname: Lü
authors.forename: Xiu-feng
authors.initials: XF
authors.lastname: Wei
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000367:Age Factors; D016976:Aggregatibacter actinomycetemcomitans / Q000302:isolation & purification*; D002648:Child; D002681:China; D003773:Dental Plaque / Q000382:microbiology*; D005260:Female; D006801:Humans; D007180:Incisor / Q000382:microbiology*; D008297:Male; D008437:Maxilla / Q000382:microbiology*; D008963:Molar / Q000382:microbiology*; D010512:Periodontal Index; D016133:Polymerase Chain Reaction; D016966:Porphyromonas gingivalis / Q000302:isolation & purification*