1. Institute of Odontology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen N Denmark
2. Danish National Metrology Institute; Lyngby Denmark
3. Department of Plant and Environmental Sciences; Faculty of Life Sciences; University of Copenhagen; Frederiksberg C Denmark
4. Department of Periodontolgy; Institute of Odontology; The Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
5. Institute of Clinical Medicine; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen N Denmark
6. Research Center for Ageing and Osteoporosis; Departments of Diagnostics and Medicine and Clinical Biochemistry; Copenhagen University Hospital Glostrup; Glostrup Denmark