1. Department of Prosthetic Dentistry; Center for Dental Medicine; Medical Center - University of Freiburg; Freiburg Germany
2. Department of Orthodontics and Orofacial Orthopedics; Center for Dental, Oral and Maxillary Medicine; University of Ulm; Ulm Germany
3. Department of Orthodontics; Center for Dental Medicine; Medical Center - University of Freiburg; Freiburg Germany
4. Clinical Epidemiology; Department of Clinical Research; University Hospital Basel; Basel Switzerland