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