TNF and periodontitis: During periodontitis, locally produced pro-inflammatory mediators such as interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) and prostaglandin E2 (PGE2), may move into the systemic circulation and subsequently exert effects on distant organs and increase and/or perpetuate an inflammatory state [20].