TNF and periodontitis: Periodontitis and peri-implantitis-related systemic low-grade inflammation can thus also be readily monitored in oral fluids and serum samples, by measuring biomarkers, including MMP-8 and -9, pro-inflammatory mediators (TNF-α, IL-6), acute phase proteinases, and CRP, to diagnostically reveal the risk (Figure 1 and Figure 2) [6,7,8,9,10,11,12,13,14,15,16].