1. Lecturer in Orthodontics, University of Sydney, NSW, Australia
2. Orthodontic PhD Student, Dundee Dental Hospital and School
3. Consultant Orthodontist, Glasgow Dental Hospital and School, 378 Sauchiehall Street, Glasgow, G2 3JZ
4. Consultant/Honorary Reader in Orthodontics, Dundee Dental Hospital and School, 2 Park Place, Dundee, DD1 4HR, UK