TNF and periodontal disorder: In periodontal diseases, inflammatory cytokines such as the interleukins (IL) and tumour necrosis factor (TNF) may promote the degeneration of inflamed periodontal tissues.7,8,9 IL-6 and TNF-α are inflammatory cytokines produced after microbial recognition and are involved in the pathogenesis of periodontal disease.10 IL-6 is thought to be involved in inflammatory cell migration and osteoclastogenesis in periodontal disease.11,12 Thus, IL-6 could play a facilitative role in the pathogenesis of periodontal disease.