Receptor activator of nuclear factor -κB ligand（RANKL）/receptor activator of nuclear factor –κB （RANK）/osteoprotegerin（OPG） system is a key pathway in osteoclast differentiation, maturation and bone resorption. This system also plays a central regulation role in bone growing and remodeling as well as in pathogenesis of periodontitis. OPG is an important mediator for the balance of bone formation and resorption for that it can inhibit differentiation and bone resorption activation of osteoclast, and induce osteoclast apoptosis.
