1. Department of Odontology, Clinical Oral Physiology Umeå University Umeå Sweden
2. Department of Community Medicine and Rehabilitation, Rehabilitation Medicine Umeå University Umeå Sweden
3. Centre for Clinical Research, Västmanland Hospital Uppsala University Västerås Sweden
4. Research Unit of Population Health University of Oulu Oulu Finland
5. Medical Research Center Oulu Oulu University Hospital and University of Oulu Oulu Finland