1. Department of Oral Surgery; Universitätsklinikum Düsseldorf; Düsseldorf Germany
2. Department of Orthodontics; Universitätsklinikum Düsseldorf; Düsseldorf Germany
3. Department of Health Sciences; Kristianstad University; Kristianstad Sweden
4. Blekinge Institute of Technology; Karlskrona Sweden
5. School of Dental Sciences; Trinity College; Dublin Ireland