1. School of Dentistry of Ribeirão Preto, University of São Paulo; Department of Dental Materials and Prosthesis; Av do Café s/nº Ribeirão Preto São Paulo Brazil 14040-904
2. University of Bern; Department of Preventive, Restorative and Paediatric Dentistry, School of Dental Medicine; Freiburgstrasse 7 Bern Bern Switzerland CH-3010
3. Ministry of Health Bahrain; UKCC (Bahrain Branch); Box 25438 Awali Bahrain
4. Plymouth University Peninsula Schools of Medicine and Dentistry; Peninsula Dental School; The John Bull Building, Tamar Science Park, Plymouth UK PL6 8BU