Affiliation: | 1. Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, , Zurich, Switzerland;2. Section of Periodontology, Faculty of Odontology, University Complutense of Madrid, , Madrid, Spain;3. Senior Statistician, Division of Biostatistics, Institute of Social and Preventive Medicine, University of Zurich, , Zurich, Switzerland |