In the patients with grade C periodontitis, there was a moderate to strong positive correlation between the IL-1β and PPD (r = 0.493; p < 0.05) and CAL (r = 0.743; p < 0.01), in addition to between the biomarker RANK-L and CAL (r = 0.443; p < 0.05) and between the biomarker IL-17A and the periodontal indices PPD (r = 0.542; p < 0.01) and CAL (r = 0.583; p < 0.01). The gene discussed is IL1B; the disease is periodontitis.