Role of Alveolar Bone in Mediating Orthodontic Tooth Movement and Relapse

In this chapter, we present a unique perspective on biological tooth movement, one that describes the adaptive nature of the alveolar bone in response to mechanical loading. We provide a new foundation to the classical “pressure-tension” theory of orthodontic tooth movement. The chapter describes the individual roles of the cell types of bone (osteoblasts, osteoclasts, osteocytes, osteoprogenitor cells, and bone lining cells) in response to tooth movement, largely focusing on the mechanosensing osteocytes. Also discussed are methods that possibly increase the rate of orthodontic tooth movement as well as the plausible role that osteocytes may have in mediating relapse. Finally, we conclude with an “overall model of tooth movement and relapse.” This chapter attempts to present an upstream mechanism to the traditional “pressure-tension” theory based on the most recent evidence.