According to what was reported in the present study, patients with CVD and periodontitis + CVD had high levels of MMP-9, associating the hypothesis that conditions that favor an increase in NO and oxidative stress, such as periodontitis and CVD, lead to an increase in systemic hs-CRP, which in turn serves as a stimulus to release MMP-9 locally (salivary) and systemically (serum) in order to protect tissues from tissue and endothelial damage caused by the inflammatory state and oxidative stress [37,38,39]. The gene discussed is MMP9; the disease is periodontitis.