1. Department of Orthodontics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
2. Department of Oral and Maxillofacial Surgery and Department of Rehabilitation, School for Health Research, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
3. Department of Orthodontics, Cleft Palate Team, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands, and private practice, Orthodontics, Almelo, The Netherlands.
4. Department of Oral and Maxillofacial Surgery and Maxillofacial Prosthetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.