1 Department of Paediatric Dentistry, School of Dentistry, National and Kapodistrian University of Athens, 2 Thivon Street, 11527, Athens, Greece. kser51@otenet.gr.
2 Department of Oral Diagnosis and Radiology, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
3 Department of Preventive and Community Dentistry, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
4 Department of Paediatric Dentistry, School of Dentistry, National and Kapodistrian University of Athens, 2 Thivon Street, 11527, Athens, Greece.