Cellular and molecular biology behind orthodontic tooth movement

This chapter reviews available reports that reveal details of the biological responses of paradental tissues and cells to applications of mechanical forces in vitro and in vivo. A review of bone cell biology as related to orthodontic tooth movement (OTM) has identified the osteoblasts as the cells that control both the resorptive and formative phases of the remodeling cycle. The main cellular and tissue reactions to orthodontic forces were perceived as being limited predominantly to the alveolar bone and periodontal ligament (PDL). However, the findings summarized in the chapter have demonstrated that orthodontic forces are transmitted to all dental and paradental tissues, both mineralized and non-mineralized, whose cells contain mechanosensing molecules and structures capable of responding to force-induced physical changes in the extracellular matrix (ECM). Orthodontics entails reactions and interactions between several systems and cell types to applied mechanical forces to teeth.