Affiliation: | (1) Centre for International Health and Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway;(2) Department of Clinical Dentistry, Preventive Dental Care, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway;(3) Department of Periodontology, Faculty of Dentistry, University of Science and Technology, Omdurman, Sudan;(4) Restorative Department, Liverpool University Dental Hospital, Liverpool, UK |