Orthodontic force on the peridontal tissue can activate a series of signal pathways resulting in peridontium and alveolar bone remodeling,which is acknowleged as the biological basis of orthodontic tooth moving.In the process of normal pHysiological bone remodeling,OCs and OBs are remained in a equilibrium state,but in a inflamatory state such as peridentitis,rheumatic arthritis,et al,the osteoclasts are over-activated which broke the bone balance,the bone resorption take the advantage; As the orthodontic force is applied,the original balance of the alveolar bone is broken,bone deposition in the tension zone while bone resorption in the pressed zone,anyway,this pHenomenon is controlled by the mechanic signal.Thus,exploring the mechanism of the periodontal remodeling during the orthondontic moving has become popularity..