1. Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China
2. Department of Orthodontics, Yantai Stomatology Hospital, Shandong, PR China
3. Department of Oral Implantology, Yantai Stomatology Hospital, Shandong, PR China
4. Central Laboratory, Peking University School and Hospital of Stomatology, Beijing, PR China