Objective       To detect the positive rate of 3 periodontal pathogens in chronic periodontitis (CP) patients living in plateau

and analyze the correlation between the prevalence and clinical periodontal parameters.       Methods       A total of 50 CP patients and 50 periodontal healthy subjects (PH) living in plateau (about 3 800 m) were recruited in this study. Clinical periodontal parameters including bleeding on probing (BOP)

probing depth (PD)

and attachment loss (AL) were recorded. Moreover

3 periodontal pat

hogens in the saliva

Porphyromonas gingivalis (Pg)

Tannerella forsythia (Tf) and Treponema denticola (Td) were detected by 16S rRNA based polymerase chain reaction (PCR).       Results       The prevalence of Pg

Tf

and Td were much higher in CP group than that in HP group (

P

0.05). Moreover

the prevalence of Pg

Tf

and Td were much significantly higher in BOP(+) group than those in BOP(-) group (

P

0.05). And there were significant statistical differences between aforementioned groups. With the increase of PD and AL

the the prevalence of Pg

Tf

and Td became higher.       Conclusion       The prevalence of periodontal pathogens Pg

Tf and Td are positively correlated with clinical periodontal parameters in chronic periodontitic patients in plateau.