1. Queen Mary University of London; Clinical and Diagnostic Oral Sciences, Barts and The London School of Medicine and Dentistry; Turner Street Whitechapel London UK E1 2AD
2. School of Dentistry, The University of Manchester; Cochrane Oral Health Group; Coupland III Building, Oxford Road Manchester UK M13 9PL
3. School of Dentistry, The University of Manchester; Coupland III Building, Oxford Road Manchester UK M13 9PL
4. University of Dundee; Dental Health Services Research Unit; The Mackenzie Building Kirsty Semple Way Dundee Scotland UK DD2 4BF