1. Department of Prosthetic Dentistry; Center for Dental Medicine; Medical Center - University of Freiburg; Freiburg Germany
2. Clinic of Fixed and Removable Prosthodontics and Dental Material Science; Center of Dental Medicine; University of Zurich; Zurich Switzerland
3. Center for Medical Biometry and Medical Informatics; Institute for Medical Biometry and Statistics; Medical Center - University of Freiburg; Freiburg Germany