1. Department of Periodontology; Faculty of Medicine; Catholic University Leuven; Leuven Belgium
2. Clinical Biology; Scientific Institute of Public Health; Brussels Belgium
3. Department of Prosthetic Dentistry; Faculty of Medicine; Catholic University Leuven; Leuven Belgium
4. Oral Imaging Center - omfs impath; Department of Imaging & Pathology; Faculty of Medicine; Catholic University Leuven; Leuven Belgium