Cytokine profiles in crevicular fluid during orthodontic tooth movement of short and long durations

Background: Orthodontic treatment induces a distortion of the extracellular matrix of the periodontium, resulting in alterations in cytoskeletal configuration. Cytokines are known to facilitate this process by inducing cellular proliferation, differentiation, and stimulation of periodontal remodeling. The aim of the present study was to measure a panel of proinflammatory cytokines (PICs) in crevicular fluid (GCF) samples during tooth movement of short and long durations. Methods: Twelve patients (11 to 27 years of age) participated in this study: six patients each for tooth movement of short and long duration. GCF sampling was done at different times, ranging from 24 hours to 4 months after force application. The profiles of PICs were analyzed with a multiplex technique. Results: PICs were elevated significantly in the early stage of tooth movement but at different time points. Interleukin (IL)-1 beta and -6 and tumor necrosis factor-alpha (TNF-alpha) reached significant levels at 24 hours; IL-8 reached a significant elevation at I month. During the linear stage of tooth movement, all cytokines were diminished to their baseline levels. The results demonstrated that IL-1 beta, -6, and -8 and TNF-alpha play a significant role during the early stage of tooth movement but not during the linear stage. Conclusions: Once the microenvironment of periodontal tissue is activated by an orthodontic force, several key PICs are produced to trigger a cascade of cellular events. The periodontal system stabilizes at a new physiological homeostasis as indicated by the downregulation of the early-phase PICs.