1. Dental Research Department, Public Dental Health Service, Örebro, Sweden
2. School of Health and Medical Sciences, Örebro University, Örebro, Sweden
3. Department of Stomatognathic Physiology, The Postgraduate Dental Education Center, Örebro, Sweden
4. Department of Clinical Dentistry–Prosthodontics, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
5. Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden