Significantly-higher levels of TRAP-5 and OPG were also found in severe periodontitis sites (478.59 and 53.3 ng/mL, respectively) in comparison to mild periodontitis sites (177.89 and 23.24 ng/mL, respectively) (p < 0.01), and healthy sites (56.79 and 13.12 ng/mL, respectively) (p < 0.01). This evidence concerns the gene TNFRSF11B and periodontitis.