Cytokines in crevicular fluid and orthodontic tooth movement

This review aimed to evaluate studies on cytokines in the gingival crevicular fluid (GCF) during orthodontic treatment, summarizing the regulation patterns of the most commonly studied cytokines and exploring their clinical implications. To achieve this, a number of key databases were searched using MESH terms and free text terms. An additional search was made by reference tracking. The procedures suggested by the QUOROM statement were followed. Data from the included studies were extracted into orthodontic mechanics, GCF sampling/handling methods, and cytokine measurements. From the 85 relevant studies identified, 23 studies could be included. Common drawbacks consisted mainly of inadequacies in the study design (e.g. short duration and small number of study subjects). The most consistent result was a peak of cytokine levels at 24 h. Associations existed between prostaglandin E-2 (PGE(2)) and interleukin-1 beta (IL-1 beta) and pain, velocity of tooth movement, and treatment mechanics. Interleukin-1 beta and PGE(2) showed different patterns of up-regulation, with IL-1 beta being more responsive to mechanical stress and PGE(2) more responsive to synergistic regulation of IL-1 beta and mechanical force. The results might be taken to support, at the cellular level, the use of light continuous forces for orthodontic treatment

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