However, OPG is decreased in periodontitis compared with healthy (nonperiodontitis) patients.36, 37, 38However, no consensus or guideline exists in terms of the correlation between the RANKL and/or OPG concentrations/or values and the disease’s clinical outcome in terms of CAL, PD, severity, and extent of periodontal degradation. This evidence concerns the gene TNFRSF11B and periodontitis.