RIPK1 and periodontitis: In the progression of periodontitis, the levels of caspase-8 were not altered, whereas higher levels of cFLIP were found in the inflamed periodontal tissue and promoted both the formation of cFLIPL-caspase-8 heterodimers and the cleavage of RIPK1 and RIPK3, thereby blocking both apoptosis and canonical RIPK1-mediated necroptosis.