1. Department of Dental Medicine; Karolinska Institutet; Huddinge; Sweden
2. Department of Oral Maxillofacial Surgery; Prosthodontics and Special Dental Care; University Medical Center Utrecht; Utrecht; The Netherlands
3. Institute of Odontology; The Sahlgrenska Academy; University of Gothenburg; Gothenburg; Sweden
4. Department of Oral Rehabilitation; Institute of Odontology; Faculty of Health Science; University of Copenhagen; Copenhagen; Denmark
5. Department of Prosthetic Dentistry; Institute for Postgraduate Dental Education; Jönköping; Sweden
6. Division of Gerodontology and Removable Prosthodontics; University of Geneva; Geneva; Switzerland
7. Faculty of Dentistry; University of Toronto; Toronto; ON; Canada