1. Clinic for Preventive and Paediatric Dentistry, Lithuanian University of Health Sciences, Kaunas, Lithuania;
2. Clinic for Preventive and Paediatric Dentistry, Lithuanian University of Health Sciences Hospital, Kaunas, Lithuania;
3. Research Unit of Oral Health Sciences, Faculty of Medicine, University of Oulu, Oulu, Finland;
4. Medical Research Center, Oulu University Hospital, Oulu, Finland