Abstract: Objective To study the relationship between Treponema denticola(Td) and sulfide levels (SUL) in periodontal pocket of the patients with chronic periodontitis. Methods Seventeen patients with chronic periodontitis were included, sulfide levels of periodontal pocket, probing depth, clinical attachment loss, and bleeding on probing were measured by Diamond Probe /Perio 2000 system. Meanwhile, Treponema denticola was detected by 16S rRNA PCR. Results The detection rate of Treponema denticola was 88.2% in the patients with chronic periodontitis. The detection rates of Treponema denticola in sulfide-negative and sulfide-positive sites were 68.5% and 43.2%, respectively, which was statistically significant between the two groups (P<0.01). The mean values of clinical attachment loss in sulfide-positive and sulfide-negative sites were (2.84±2.33) mm and (1.83±1.60) mm, respectively, which was statistically significant between the two groups(P<0.01). The mean values of probing depth in sulfide-positive and sulfide-negative sites were (4.20±1.57) mm and (3.83±1.30) mm, respectively, which showed no statistical significance (P＞0.05). The detection rate of BOP(+) in sulfide-positive sites was 92.5%, greater than that of 75.8% in sulfide-negative sites, which showed significant difference between the two groups (P<0.01). Conclusion Sulfide levels in periodontal pocket of the patients with chronic periodontitis may reflect the distribution of periodontal Treponema denticola.

Key words: chronic periodontitis, sulfide levels, Treponema denticola, periodontal pocket