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