Therefore, one of the major barriers to our exploitation of this knowledge (e.g., in the identification of key biomarkers) is gaining a holistic understanding of the relative roles of the vast array of known mediators in the pathogenesis of periodontitis and currently, in terms of biomarker identification, we still rely on information from “candidate” mediator studies and the literature is dominated by many studies on a limited number of these candidate markers such as IL-1β, OPG, and MMP-8. This evidence concerns the gene MMP8 and periodontitis.