1. Clinic of General, Special Care and Geriatric Dentistry, Center of Dental Medicine, University of Zurich
2. Department of Oral Health & Medicine, University Center for Dental Medicine Basel UZB, University of Basel
3. Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern
4. Division of Gerodontology, Department of Prosthodontics, Dental School, National and Kapodistrian University of Athens
5. Department of Preventive and Community Dentistry, The University of Iowa College of Dentistry and Dental Clinics