1. Dental Public Health, Faculty of Dentistry, The University of Hong Kong, 3B20, 3/F, Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong, China
2. Dental Health Services Research Unit, University of Dundee, Scotland, UK
3. The University of Manchester, Manchester Academic Health Science Centre, Cochrane Oral Health Group, School of Dentistry, Manchester, UK
4. Clinical and Diagnostic Oral Sciences, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK