1. Department of Pedodontics and Orthodontics, Institute of Dentistry, P.O. Box 41, FIN-00014 University of Helsinki, Finland, Helsinki University Central Hospital, Department of Oral and Maxillofacial Diseases
2. Department of Pedodontics and Orthodontics, Institute of Dentistry, P.O. Box 41, FIN-00014 University of Helsinki, Finland, Institute of Biotechnology, University of Helsinki, Finland
3. Department of Pedodontics and Orthodontics, Institute of Dentistry, P.O. Box 41, FIN-00014 University of Helsinki, Finland