Several polymorphisms in the promoter region of TNF-α have been identified, and the 308G/A and 863C/A polymorphisms may contribute to the susceptibility of periodontitis according to a meta-analysis.22 The TNF level was also shown to be elevated in the GCF122 and serum123 of chronic periodontitis patients, while no decrease in TNF was observed after NSPT. Here, TNF is linked to chronic periodontitis.