1. School of Dental Sciences, Newcastle University, Newcastle upon Tyne, UK
2. Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK
3. School of Health Sciences, Bangor University, Bangor, UK
4. Division of Pediatric and Public Health, UNC Adams School of Dentistry, University of North Carolina, Chapel Hill, NC, USA
5. Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK