1. School of Dentistry, University of Dundee, Dundee, UK
2. Dental Health Services Research Unit, University of Dundee, Dundee, UK
3. School of Dentistry, University of Leeds, Leeds, UK
4. Institute of Health and Society, Newcastle University, Newcastle, UK
5. School of Clinical Dentistry, University of Sheffield, Sheffield, UK
6. Newcastle Clinical Trials Unit, Newcastle University, Newcastle upon Tyne, UK
7. School of Dental Sciences, Newcastle University, Newcastle upon Tyne, UK
8. School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
9. Institute of Dentistry, Queen Mary University of London, London, UK