Prior study has detected the significantly increased levels of IL-6, IL-8 and TNF-α in the serum and gingival crevicular fluid of patients with periodontitis.17,18, 19 In our study, the levels of serum inflammatory factors IL-6 and TNF-α in the enrolled patients were improved after 12 months of treatment compared with those before treatment, with more significant decrease in the study group than those in the control group. This evidence concerns the gene TNF and periodontitis.