MMP8 and Peri-Implantitis: aMMP-8 (also known as active collagenase-2 or neutrophil collagenase) belongs to the family of tissue destructive enzymes related to periodontitis and peri-implantitis, where the elevation of activated MMP-8 to pathological levels plays an important role in the initiation and progression of the tissue destructive disease and related attachment loss [14,15,16].