1. Department of Periodontology, Peking University School and Hospital of Stomatology, National Clinical Research Center for Oral Disease, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Beijing, China
2. NHC Research Center of Engineering and Technology for Computerized Dentistry, Beijing, Beijing, China
3. Department of Restorative Dentistry, University of Washington, Seattle, United States of America