TNFSF11 and inflammatory response: In addition to pathophysiological changes in connective tissues, periapical inflammation also leads to alveolar bone resorption.3 Bone turnover depends on the equilibrium between osteoblast-mediated bone formation and osteoclast-mediated bone destruction, and the osteoclast activities are regulated by the receptor activator of NF-kappa B (RANK), its ligand RANKL, and the decoy receptor of RANKL, osteoprotegerin (OPG).10 The binding of RANKL to RANK drives the maturation of osteoclasts.