TNF and periodontitis: The results of correlation analysis showed that in chronic periodontitis, the miR-34a expression level was notably positively correlated with GI, BI, PD, AL, IL-1β, IL-6, TNF-α, NF-κB p65 mRNA, and TLR4 mRNA in GCF of chronic periodontitis (P < 0.05) (Table 6 and Figure 1).