1. Department of Oral and Maxillofacial Surgery, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
2. Department of Social Dentistry and Behavioural Sciences, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University, Amsterdam, the Netherlands
3. Department of Psychiatry, Erasmus University Medical Centre, Rotterdam, the Netherlands
4. School of Health Sciences, Salford University, Manchester, UK