1. Department of Periodontology and Implantology, Department of Dentistry, Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
2. All Saints Green Dental Practice, Norwich NR1 3LY, UK
3. Department of Surgical Clinical Sciences CHIR-ORHE, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1050 Brussels, Belgium
4. Department of Educational Sciences EDWE-LOCI, Faculty of Psychology and Educational Sciences, Vrije Universiteit Brussel, 1050 Brussels, Belgium
5. Department of Periodontology and Oral Implantology, Faculty of Medicine and Health Sciences, University of Ghent, 9000 Gent, Belgium