Detection Of Treponema Denticola From Subgingival Plaque Of Chronic Periodontitis By PCR

Objectives: To detect the Treponema denticola ( Td ) in disease sites and healthy sites subgingival plaque of chronic periodontitis using two different gene fragments by PCR and investigate the relationship between the presence of Td and periodontal parameters. Methods: subgingival plaque collected from disease sites and healthy sites of 58 patients with chronic periodontitis , and treated with l%Triton X-100 and 100℃ for 10 minutes to prepare DNA templates. The fragments of tdpA gene which encode 53 kDa major surface protein and 16s rRNA gene were detected by PCR. Results: among 58 subgingival plaque samples from disease sites, the positive rates of Td tdpA and 16s rRNA gene were 58.6% and 81.0% respectively and in healthy sites the positive rates was 8.62% and 15.5%. the sequencing results of tdpA gene fragments demonstrated that it had 94% similarity with the reported at Genebank . Conclusion: (1) The detection rate of Td in disease sites was much higher than the healthy sites (P< 0.01) and close related to the chronic periodontitis, (2) PCR is the sensitive and reliable method to detect Td and detection rate of 16s rRNA gene fragments were higher than tdpA gene. (3 ) Td infection was close related to the severity of clinical attachment loss and not directly related to pocket depth and gingival index.