1. Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China
2. Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi'an, China
3. Department of Orthodontics, School of Stomatology, KunMing Medical College, Kunming, China
4. Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi'an, China
5. Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China