1. Department of General Dentistry, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, P.R. China
2. Department of Orthodontics, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
3. Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Yubei District, Chongqing, P. R. China