Orthodontic forces increase tumor necrosis factor alpha in the human gingival sulcus

The production of cytokines has been associated with the biology of tooth movement in animal populations. The purpose of this study was to measure tumor necrosis factor-alpha (TNF) directly in the human gingival sulcus before and after the application of an orthodontic force. To recover TNF from the sulcus, paramagnetic beads, coated with monoclonal antibodies for TNF, were introduced into the gingival sulcus of 50 teeth undergoing orthodontic tooth movement (by two force systems) in 20 patients. Retrieval was performed by a permanent magnetic device designed to fit the periodontal sulcus. The samples were taken before force application (controls), and at a fixed time after force application. The amount of immunoabsorbed TNF was quantified with an immunochemical assay. There was a greater than twofold increase in TNF recoverable from the gingival sulcus after application of orthodontic forces (mean of 12.9 ng vs 30.5 ng). A Student's t test for paired samples demonstrated statistical significance at p < 0.01. We conclude that the quantity of paradental TNF, found in human gingival sulcus, is elevated during tooth movement. The source may be from the adjacent gingiva, but more likely the compressed periodontal ligament and the resorbing bone adjacent to the root surface.