[Bone remodeling induced by mechanical force during orthodontic treatment]

The cranium is a small portion of the body but has the most complex structure composed of more than 20 small parts. The cranium is a unique tissue that is equipped with teeth. Tooth misalignment is corrected by orthodontic treatment, in which bone surrounding the tooth root undergoes remodeling by applying special devices. There is a wider individual variation in the shape of the mandible, a component of the cranium, than other parts of the body, which is partly due to the difference of the mechanical loading onto the bone by mastication and occlusion. Thus, mechanical loading has crucial roles in cranial bone metabolism. It has been recently revealed that osteocytes have crucial functions in the regulation of remodeling of the jawbone and the alveolar bone, by producing cytokines IGF-1 and RANKL. The mechanisms by which osteocytes produce these cytokines upon mechanical stimuli are addressed in many studies. Insights obtained by these studies can be applied to orthodontic treatment in the future.