In a cross-sectional study, the levels of OPG and RANKL were analyzed in the saliva of chronic periodontitis patients and it was found that gingival index (GI) (p=0.024), PPD (p<0.001) and clinical attachment loss (CAL) (p=0.002) were significantly correlated with RANKL/OPG ratio. All the clinical periodontal parameters were also significantly correlated with RANKL levels (p<0.05) [30]. The gene discussed is TNFRSF11B; the disease is periodontitis.