Despina Koletsi1, Nikolaos Pandis2. 1. London School of Hygiene and Tropical Medicine, University of London, London, United Kingdom; private practice, Athens, Greece. 2. Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine/Medical Faculty, University of Bern, Bern, Switzerland; private practice, Corfu, Greece.