1. Department of Oral and Maxillofacial Diseases, Helsinki University Hospital, Helsinki, Finland
2. Nordic Institute of Dental Materials, NIOM, Oslo, Norway
3. Research Unit of Oral Health Sciences, University of Oulu, Oulu, Finland
4. Oral and Maxillofacial Department, Medical Research Center Oulu, Oulu University Hospital, Oulu, Finland
5. Department of Biomaterials Science and Turku Clinical Biomaterials Centre, TCBC Institute of Dentistry, University of Turku, Finland
6. Welfare Division, City of Turku, Finland