1. Department of Social Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University, Amsterdam, The Netherlands;
2. School of Pharmacy, Keele University, Keele, UK;
3. Department of Conservative Dentistry, Translational Health Economics Group, Heidelberg University, Heidelberg, Germany;
4. Department of Dentistry – Quality and Safety of Oral healthcare, Radboud University Nijmegen, Nijmegen, The Netherlands;
5. Oral Health Services Research Centre, University College Cork Dental School, Cork, Ireland