**1. Introduction**

When more than 100 years ago the world knew about the theory about the regulation of the tooth movement, cytokines were unknown to science [1]. The first experimental evidence that supported the assumption about cytokines being the potential regulators of the reshaping process (remodeling) of bones during the orthodontic treatment was obtained approximately 20 years ago [2]. Since then, until today, the efforts of researchers last in order to clarify molecular events with cytokines as mediators, which follow the orthodontic tooth movement.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The role of cytokines in the orthodontic tooth movement is considered in the context of inflammation, which occurs at the very beginning of this process as a reaction to the mechanical pressure and represents necessary precondition for the realization of all its subsequent levels. In the conjunction of mechanical and biological mechanisms, which move the teeth during the orthodontic treatment, cytokines are given great importance for their feature of transmission of biochemical signals among numerous cells of various kinds reacting to orthodontic forces. Binding themselves to specific receptors at membranes of these cells, cytokines cause in them the biochemical changes responsible for the signal transmission to corresponding genes in these cells and, consequently, to the change of gene expression in them. This orthodontic tooth movement causes the features of unusually complex processes, whose different degrees—each individually and all together—are regulated by the network of positive and negative feedbacks, in which cytokine molecules act as mutual activators or inhibitors [3].

periodontal ligament remain clinically intact and surrounding bone is reorganized. The final outcome of these activities (the speed of orthodontic movement of teeth) may be defined as a phenotypic expression of numerous gene-controlled mechanisms, which connects the orthodontic tooth movement with hereditary basis, i.e., hereditary variations of factors which

The Role of Cytokines in Orthodontic Tooth Movement http://dx.doi.org/10.5772/intechopen.80078 37

The cells of alveolar bones and periodontal ligament, gingiva, and tooth pulp react to the effect of orthodontic forces after the remodeling of extracellular matrix (ECM), which surrounds them [11]. Dental and periodontal cell responses to the applied mechanical force comprise interactions of intracellular and extracellular structural elements and mutual influences of the effects of various biochemical structures. The nature of changes in the process of reshaping is determined by the combinatory of interactions, which is different at different levels of the tooth movement [12]. The scheme no. 1 presents the main events in dental tissues, which fol-

**3. Orthodontic tooth movement and biological mechanisms of** 

**4. Orthodontic tooth movement and the change in the structure of** 

**5. Orthodontic tooth movement and reorganization of blood vessels**

Blood vessels in periodontal ligament actively participate in the remodeling of dental tissues, which is related to the orthodontic tooth movement. Under the influence of mechanical forces,

The function of all cells in mechanic-sensitive dental tissues is closely related to the ECM, which surrounds them and makes the corresponding microenvironment for cell activities, which emerge after the application of orthodontic force. The orthodontic treatment leads primarily to ECM periodontium deflection, which results in the changes of cytoskeleton structure of cells anchored in ECM. ECM is multicomponent tissue, which enables the transmission of mechanical signals to the corresponding cells and thus the occurrence of changes in the structure and function of a certain tissue [11]. The structural components of ECM (collagen, fibronectin, laminin, elastin, proteoglycans, hyaluronic acid, etc.) bind with the adhesive receptors at cells called integrins, via which the mechanical stimuli are transmitted into the cell causing the changes of cytoskeleton structures. The application of mechanical force outside disturbs the integrin receptors at fiber areas of periodontal ligament and gingiva and bone cells (osteoblast, osteoclast, osteocytes), and their adaptive response may increase or decrease the creation of integral elements of ECM in them and thus influence the change of

**reshaping of the mechanic-sensitive dental tissue**

the mass and morphological appearance of the bone [13].

participate in this process [10].

low orthodontic movement of the tooth.

**cytoskeleton**
