1. Department of Biomaterials; Radboudumc; Nijmegen The Netherlands
2. Department of Implantology and Periodontology; Radboudumc; Nijmegen The Netherlands
3. Ewald M. Bronkhorst, Department of Preventive and Curative Dentistry; Radboudumc; Nijmegen The Netherlands
4. Department of Prosthetic Dentistry; University of Turku; Turku Finland