1. National Clinical Research Center for Oral Diseases and State Key Laboratory of Military Stomatology and Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, China
2. Department of Stomatology, Peking University People’s Hospital, Beijing, China
3. Ruica Dental Lab., Beijing, China