1. Department of Prosthetic Dentistry, Folktandvården Eastman Institute, Stockholm, Sweden
2. Unit of Oral Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
3. Academic Center for Geriatric Dentistry, Stockholm, Sweden
4. Department of Prosthetic Dentistry, Institute for Postgraduate Dental Education, Jonkoping, Sweden