MMP8 and chronic periodontitis: According to a study conducted in 199926, the matrix metalloproteinase 8 (MMP-8) is the main interstitial collagenase in the gingival crevicular fluid (GCF) of patients with chronic periodontitis as well as in the peri-implant sulcular fluid of patients with peri-implantitis, representing 90-95% of collagenolytic activity among the collagenases involved in this process.