Chapter 57 - Biological Mediators and Molecular Changes to Orthodontic Force

Abstract

Application of a force to a tooth initiates a series of histological, cellular, biological, and molecular changes in the tension and compression sites in the periodontium of the tooth. During the early stages of orthodontic tooth movement (OTM), little actual movement is evident. However, a number of molecular changes reflective of important biological events such as inflammation, extracellular remodeling, and mechanosensing by osteocytes are occurring in the periodontium, mediated by members of the Interleukin and Tumor Necrosis Factor family of proteins, prostaglandins, and metalloproteinases. Bone resorption and deposition predominate in the later stages of tooth movement, and a number of proteins in the RANK/RANKL/osteoprotegerin and the RUNX2 signaling pathways have been shown to be expressed in the periodontium of teeth subject to different magnitude and duration of orthodontic forces. So far, all genes shown to be involved in OTM are those documented to play important roles in similar processes in the body, i.e., there is no unique gene that regulates OTM. The challenge in the field of OTM studies lies in being able to integrate the numerous signaling networks in the diverse parts of the periodontium during OTM. This challenge can only be met by creative approaches and ideas in a multi-disciplinary setting.