1. Department of Orthodontics, Aachen University, Aachen, Germany
2. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
3. Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
4. Division of Periodontics, School of Dentistry, University of Maryland, Baltimore, MD, USA
5. Department of Orthodontics, Universitätsklinikum Düsseldorf, Düsseldorf, Germany
6. Department of Orthodontics, University of Bonn, Bonn, Germany