MMP8 and periodontitis: Other studies revealed that a shorter duration of such therapy (3 months) could also decrease the levels of MMP-8 (matrix metalloproteinase-8), MAF (macrophage-activating factors), and SIRT1 (an NAD+-dependent histone deacetylase) in saliva, while increasing the serum level of T-SOD (total superoxide dismutase, an antioxidant enzyme) in patients with periodontitis [100].