TNF and periodontitis: TNF-α and IL-1β, as two of the important pro-inflammatory mediators, were significantly up-regulated in the process of periodontitis [20, 21], which are actively involved in jeopardizing periodontal tissues by affecting the activities of leukocytes, oteoclasts and collagenolytic enzyme MMPs to mediate alveolar bone resorption and collagen destruction [22, 23].