[Comparative analysis of 6 kinds of bacteria in the subgingival plaque in different types of patients with periodontal diseases].

Purpose: To detect the existence of Aa,Pg,Tf,Cr,Ec and Pn in the subgingival plaque, and determine their relationships among different types of periodontal diseases.
Methods: Dental plaques from 120 subjects were sampled, including 40 volunteers with health periodontal status(Group A) , forty patients with dental plaque-induced gingival diseases(Group B) and 40 patients with moderate or severe chronic periodontitis (Group C) . These samples were detected based on bacterial composition using the terminal restriction fragment length polymorphism of 16S rRNA genes by multiple-polymerase chain reaction. The data was analysed with SPSS 13.0 software package for Chi-square test.
Results: The detection rate of Pn, Cr and Pg had significant differences between group A and B. The detection rate of Ec, Cr, Pg, Aa and Tf had significant differences between group C and B. The detection rate of Ec, Pn, Cr, Pg, Aa and Tf had significant differences between group A and C.
Conclusions: The rate of Ec, Pn, Cr, Pg and Tf detected in moderate or patients with moderate or severe chronic periodontitis are significantly higher than that in healthy subjects, indicating that these bacteria have certain correlation with chronic periodontitis. The rate of Ec, Cr, Pg and Tf detected in severe chronic periodontitis are significantly higher than that in dental-induced gingivitis, suggesting their close relationship with the progress of periodontal disease.