Abstract: Orthodontic tooth movement depends on the remodeling of periodontal tissues, and the alveolar bone remodeling depends mainly on osteoclast and osteoblast activity. Osteoclast derived from hematopoietic stem cells, a kind of multinucleated giant and highly differentiated cells， which is the main functional cell of bone resorption in the pressure side during orthodontic tooth movement. The number and function of osteoclasts is one of the main factors determining the efficiency of orthodontic tooth movement. The differentiation of osteoclast is influenced via a variety of systemic factors or local factors directly or indirectly, thus affecting the absorption of bone remodeling, such as hormones, drugs, orthodontic force local loading, periodontal status and various cytokines. Research about these factors has certain guiding significance for the clinical accelerating tooth movement or increasing anchorage and reducing unnecessary tooth movement.

Key words: Osteoclast, Orthodontic tooth movement, Hormone, cytokine, drugs