1. Department of Orthodontics, Shanghai Key Laboratory of Stomatology, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China
2. Department of Orthodontics, Shanghai Xuhui District Dental Disease Prevention and Control Institute, Shanghai 200001, P.R. China
3. Department of Orthodontics, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China