A negative association was reported between MMP-9 and Fusobacterium nucleatum, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Prevotella nigrescens, in GCF in individuals with chronic periodontitis, suggesting an anti-inflammatory effect of MMP-9 in periodontitis [58]. The gene discussed is MMP9; the disease is chronic periodontitis.