Abstract: Objective: To detect the amount of Pg in saliva of periodontitis patients and periodontal healthy subjects, then assess differences in the Pg number between the groups. Methods: We examined quantity of Pg in saliva of 20 chronic periodontitis and 20 periodontal health by Pg specific genes Arg-gingipain adopting SYBR Green real-time fluorescent quantitative PCR technology. T test was used to analyze the differences of Pg engraftment among all groups. Results: In samples of chronic periodontitis, the number of Pg was 1.78×10³-1.99×10⁵ and positive rates was 85%; While in samplels with periodontal healthy subjects, the number of Pg was 2.19×10³-2.30×10³,and positive rates was 10%. The difference of saliva Pg number between chronic periodontitis and periodontal healthy subjects was significant in statisties (P＜0.05). Conclusion: The number of Pg in chronic periodontitis saliva increased highly than in periodontal healthy subjects. In the future research and prevention, not only Pg in the gingival crevicular fluid should be detected, but also we should pay attention to it in the saliva.

Key words: Real-time fluorescent quantitative , PCR , Chronic periodontitis , Porphyromonas gingivalis, Saliva