TNFRSF11B and periodontitis: On the one hand, osteoclasts differentiate and activate in the presence of macrophage colony-stimulating factor (M-CSF) and RANKL, which increase during periodontitis mainly by Th17 activity; while on the other hand, osteoblasts produce osteoprotegerin (OPG), the RANKL soluble decoy, which is partly mediated by Treg lymphocyte activity during periodontitis (17, 23, 27–31).