1. * Department of Orthodontics, Faculty of Dentistry, Aristotle University of ThessalonikiGR-54124, Greece,
2. ** Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7 CH-3010, Switzerland and
3. *** Private Practice, Frankfurter Strasse 610, DE-51145, Cologne, Germany