1. Department of Prosthodontics; School of Dentistry; National and Kapodistrian University of Athens; Athens Greece
2. Department of Restorative Dentistry & Biomaterials Sciences; Harvard School of Dental Medicine; Boston MA USA
3. Department of Dentistry; Chi-Mei Medical Center; Liouying Taiwan
4. Clinic for Fixed and Removable Prosthodontics and Material Science; University of Zurich; Zurich Switzerland
5. Griffith University; School of Dentistry and Oral Health; Gold Coast Queensland Australia