TNFRSF11B and periodontal disorder: Kinney et al. [39] demonstrated that by examining the salivary concentrations of pathogens, matrix metalloproteinase-8 and -9 (MMP-8, MMP-9), calprotectin, osteoprotegerin (OPG), tumor necrosis factor (TNFα), interferon (IFN), and numerous interleukins (ILs), one can examine the progression or non-progression of periodontal disease.