1. State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, P. R. China
2. Orthopedic Research Institute, Department of Orthopedics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, P. R. China