1. Department of Prosthetic Dentistry, Faculty of Dentistry Complutense University of Madrid Madrid Spain
2. Department of Prosthodontics, Faculty of Dentistry Istinye Univeristy İstanbul Turkey
3. Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine University of Bern Bern Switzerland
4. Department of Restorative, Preventive and Pediatric Dentistry, School of Dental Medicine University of Bern Bern Switzerland
5. Division of Restorative and Prosthetic Dentistry The Ohio State University Columbus Ohio USA
6. Department of Restorative Dentistry, School of Dentistry University of Washington Seattle Washington USA
7. Kois Center University of Washington Seattle Washington USA
8. Department of Prosthodontics, School of Dental Medicine Tufts University Boston Massachusetts USA