1. State Key Laboratory of Military Stomatology, Center for Tissue Engineering, School of Stomatology, Fourth Military Medical University, Xi’an, China
2. Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
3. Guanghua School of Stomatology, South China Center of Craniofacial Stem Cell Research, Sun Yat-sen University, Guangzhou, China