Nonetheless, their elegant 24/7 tongue sensor assay is not MMP-specific for the main collagenolytic MMP, MMP-8, upregulated and activated in periodontitis- and peri-implantitis-affected periodontal and peri-implant tissue, gingiva and oral fluids, including saliva, GCF, PISF, and mouth rinse. Here, MMP8 is linked to periodontitis.