Introduction: Cytokines are the important factors in the progression of periodontal diseases. The aim of this study was to find out the effect of the first phase of the periodontal therapy on the amount of existing IL-17 and IL-23 in gingival crevicular fluid in patients with severe periodontitis and in the control group.

Methods: In this clinical trial intervention study,after purifying the parts which were under consideration in 22 patients with severe periodontitis, gingival crevicular fluid was gathered using periopaper located within the gingival sulcus, Then, the first phase of periodontal therapy was carried out and sample taking from the same parts was conducted after 4 weeks. The same phase was carried out on 24 healthy patients (control group). All patients were selected from the Department of Periodontology, Tehran Islamic Azad University Dental Branch. Since the data did not have a normal distribution, therefore, nonparametric tests were used for comparing the groups (Mann-Whitney U Test). A p≤0.05 is considered as significant.

Results: The results showed that there was a meaningful and significant difference between the IL-17 viscosity before (p<0005) and after (p<005) the therapy and IL-23 viscosity before (p<0001) and after (p<001) the therapy between the two groups.

Conclusions: According to the results of the present study, we can conclude that IL-17 and IL-23 have a significant role in the pathogeneses of periodontal disease.