Numerous oral biomarkers have been investigated in relation to periodontitis, and several studies [8,9,10,11] have found elevated levels of aMMP-8, but not total/latent MMP-8, to differentiate periodontitis from both gingivitis and healthy periodontium, and to precede future tissue destruction [14,15,16,56,57,58,59,60,61,62,63,64]. The gene discussed is MMP8; the disease is periodontitis.