1. Department of Oral and Maxillofacial Surgery; Lanzhou General Hospital, Lanzhou Command of PLA; BinHe 333 South Road, Lanzhou 730052 China
2. Department of Orthodontics; School of Stomatology, Lanzhou University; Lanzhou China
3. Rege Lab of Tissue Engineering, Department of Bioscience, Faculty of Life Science; Northwest University; Xi'an China
4. Department of Oral and Maxillofacial Surgery, School of Stomatology; The Fourth Military Medical University; Xi'an China