1. Academy for Oral Implantology; Private Hospital; Vienna Austria
2. Clinic of Fixed and Removable Prosthodontics and Dental Material Science; Center of Dental Medicine; University of Zurich; Zurich Switzerland
3. Aesthetic Dent; Private Practice; Szczecin Poland
4. University of Santiago de Compostela; Santiago de Compostela Spain
5. Division of Prosthodontics; School of Dental Medicine; University of Connecticut; Farmington CT USA