1. Private Practice Hürzeler/Zuhr; Munich Germany
2. Department of Periodontology; Centre for Dental, Oral, and Maxillofacial Medicine (Carolinum); Johann Wolfgang Goethe-University Frankfurt/Main; Frankfurt Germany
3. Clinic for Fixed and Removable Prosthodontics and Dental Material Science; University of Zurich; Zurich Switzerland
4. Schupbach Ltd; Service and Research for Histology, Microscopy and Imaging; Horgen Switzerland
5. Department of Operative Dentistry and Periodontology; University Dental School; University of Freiburg; Freiburg Germany