MMP-8, also referred to as collagenase-2, is the primary collagenase in the gingival connective tissue in periodontitis cases and accounts for 90–95 % of the collagenolytic activity in gingival crevicular fluid (GCF), highlighting its critical role as an indicator of periodontitis [11,12,[14], [15], [16], [17], [18], [19], [20], [21]]. The gene discussed is MMP8; the disease is periodontitis.