RANK/RANKL/OPG during orthodontic tooth movement

Abstract

Orthodontic tooth movement is induced by mechanical stimuli and facilitated by remodeling of the periodontal ligament (PDL) and alveolar bone. A precondition for these remodeling activities, and ultimately for tooth displacement, is the occurrence of an inflammatory process. This review covers current knowledge regarding the role of the receptor activator of nuclear factor-kappa (RANK), receptor activator of nuclear factor-kappa ligand (RANKL), and osteoprotegerin (OPG) in periodontal tissue reactions, in response to orthodontic forces. It has been found that concentrations of RANKL in GCF increased during orthodontic tooth movement, and the ratio of concentration of RANKL to that of OPG in the GCF was significantly higher than in control sites. In vivo studies have shown the presence of RANKL and RANK in periodontal tissues during experimental tooth movement of rat molars, and that PDL cells under mechanical stress may induce osteoclastogenesis through upregulation of RANKL expression during orthodontic tooth movement. Considering the importance of RANK, RANKL, and OPG in physiologic osteoclast formation, it is reasonable to propose that the RANKL/RANK/OPG system plays an important role in orthodontic tooth movement.