Objective To detect the presence of Tannerella forsythus(Tf)and Prevotella intermedia (Pi) 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 primary school. The supragingival plaque sample was collected from the mesiobuccal and labial surfaces of the right maxillary central incisor ( FDI 1 ) and the right maxillary first molar ( FDI 6 ). 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 Tf was 40. 3% ( 118/293 ) and Pi was 46. 4% ( 136/293 ) in supragingival plaque. The detection rates for Tf and Pi in molars were much higher than those in incisors( P ＜0. 01 ). The detection rate of Tf and Pi was positively related to BOP + and PD. The detection rate for Pi decreased gradually with age, and the detection rate for Tf was highest in the group aged 7 to 8 and the detection rates for Tf and Pi were higher in the gingiva with BOP + than that with BOP - ( P ＞ 0. 05 ). The detection rates for Tf 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 Tf and Pi in molars were much higher than those in incisors, and the presence of Tf and Pi in supragingival plaque was related to periodontal parameters.

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 ram. 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.