1. Department of Maxillo-Facial Surgery, Pediatric Surgery Clinic, Institute of Mother and Child, Kasprzaka Str. 17a, 01-211 Warsaw, Poland
2. Speech and Language Pathology Clinic, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland
3. Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, 3010 Bern, Switzerland
4. Department of Orthodontics, Institute of Dentistry and Oral Sciences, Palacky University Olomouc, Palackého 12, 779 00 Olomouc, Czech Republic
5. Department of Orthodontics, Jagiellonian University in Krakow, Montelupich 4, 31-155 Krakow, Poland