FAS and chronic periodontitis: Soluble FasL was found to be higher in gingival crevicular fluid obtained from patients with chronic periodontitis than in healthy controls (Dabiri et al., 2016) and the jawbone of human foetuses revealed the expression of Fas on both osteoblasts and osteoclasts and of Fas ligand on osteoblasts (Hatakeyama et al., 2000).