1. Orthodontist, Department of Stomatology, Xiamen Branch, Zhongshan Hospital, Fudan University, Xiamen, P. R. China.
2. Orthodontist, Department of Orthodontics, Medical Center of Stomatology, The Second Xiangya Hospital, Central South University, Changsha, P. R. China.
3. Graduate student, Department of Orthodontics, Medical Center of Stomatology, The Second Xiangya Hospital, Central South University, Changsha, P. R. China.
4. Associate Professor, Department of Orthodontics, Medical Center of Stomatology, The Second Xiangya Hospital, Central South University, Changsha, P. R. China.