1. Biomedicum Helsinki, Institute of Dentistry, Research Laboratory, University of Helsinki, P.O. Box 63, Haartmaninkatu 8, 00014 Helsinki, Finland
2. Department of Diagnostics and Oral Medicine, Institute of Dentistry and the Oulu Center for Cell-Matrix Research, University of Oulu, P.O. Box 5281, 90014 Oulu, Finland
3. Oulu University Hospital, Oulu, Finland
4. Department of Oral and Maxillofacial Diseases, Helsinki University Hospital, Helsinki, Finland