Indeed, a recent systematic review that included two studies from our research group (Leppilahti, Hernandez-Rios et al., 2014, Baeza, Garrido et al., 2016), considered MMP-8 as the most useful single biomarker to aid in the clinical diagnosis of periodontitis [26], with medians of sensitivity and specificity of 76.7% and 92%, respectively. Here, MMP8 is linked to periodontitis.