1. Department of Diagnostic and Biological Sciences; University of Minnesota; Minneapolis MN USA
2. Department of Prosthodontics; University of Ljubljana; Ljubljana Slovenia
3. Department of Prosthodontics; Showa University; Tokyo Japan
4. Department of Prosthodontics; University of Zagreb; Zagreb Croatia
5. Department of Prosthetic Dentistry; Centre of Oral Rehabilitation; Norrköping Sweden
6. Department of Prosthodontics; University of Pécs; Pécs Hungary
7. Department of Health Behavior; University of Alabama; Birmingham AL USA
8. Department of Prosthetic Dentistry; Center for Dental and Oral Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany