1. Department of Endodontics, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, Oslo, Norway
2. Center for Oral Health Services and Research (TkMidt), Trondheim, Norway
3. Department of Public health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
4. Department of Cariology and Gerodontology, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, Oslo, Norway