TNF and chronic periodontitis: With regard to therapeutic biomarkers, several studies have hypothesised that inflammatory cytokines, including interleukin (IL)-1 and tumour necrosis factor (TNF)-α, may be used as biomarkers to assess therapeutic outcomes in chronic periodontitis, based on studies where a reduction in inflammatory cytokines in the gingival crevicular fluid (GCF) was observed in response to nonsurgical periodontal therapy (3,4).