1. Division of Orthodontics, Dental Clinics Zwolle, Zwolle, The Netherlands
2. Department of Oral and Maxillofacial Surgery, University of Groningen, University Medical Center, Groningen, The Netherlands
3. Department of Orthodontics, Seoul National University School of Dentistry, Seoul, Republic of Korea
4. Department of Orthodontics and Dentofacial Orthopaedics, School of Dental Medicine, University of Bern, Bern, Switzerland