1. Department of Periodontology, Department of Oral Health Sciences, KU Leuven and Dentistry, University Hospitals, KU Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium.
2. Oral Imaging Centre, Department of Oral Health Sciences, KU Leuven and Dentistry, University Hospitals, KU Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium.