MMP9 and periodontitis: Periodontitis‐related pro‐inflammatory cytokines, such as TNF‐α and IL‐1β produced from host cells exposed to dental biofilm, produce a synergistic effect by increasing the synthesis of IL‐6, IL‐8, prostaglandin‐E2, MMPs, such MMP‐8, MMP‐9, and MMP‐13, whose primary substrate is collagen type I and III present in the alveolar bone, as well as CX3CL1, which perpetuates the inflammatory state and results in further destruction of periodontal tissues.48, 49