1. State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology The Fourth Military Medical University Xi'an Shaanxi China
2. Air Force Medical Center Fourth Military Medical University Beijing China
3. Department of Oral Function and Prosthetic Dentistry, College of Dental Science Radboud University Nijmegen Medical Center Nijmegen The Netherlands