1. Faculty of Medicine and Health Sciences; Dental School; Department of Periodontology and Oral Implantology; Ghent University; Ghent Belgium
2. Faculty of Medicine and Pharmacy; Dental Medicine; Department of Periodontology and Oral Implantology; Free University of Brussels (VUB); Brussels Belgium
3. Faculty of Medicine and Pharmacy; Dental Medicine; Free University of Brussels (VUB); Brussels Belgium
4. Faculty of Odontology; Department of Prosthodontics; Malmö University; Malmö Sweden