TNFSF11 and periodontitis: Periodontitis is a chronic inflammatory disease with a multifactorial pathogenesis where bacterial load, host immune response, systemic inflammatory diseases and environmental factors, collectively contributing to the destruction of tissue and alveolar bone.28 In an attempt to investigate the effect of mPGES‐1 inhibitors on osteoclast formation and bone resorption, we used a co‐culture model of fibroblast‐like PDL cells and osteoclast progenitor cells RAW 264.7 as well as PBMCs stimulated by LPS or RANKL.