1. Department of Restorative Dentistry, Gerald Niznick College of Dentistry University of Manitoba, Winnipeg, MB R3E 0W3, Canada
2. Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA
3. Department of Prosthodontics, University of Iowa College of Dentistry, Iowa City, IA 52242, USA
4. Division of Restorative Dental Sciences, Clinical Sciences Department, Ajman University College of Dentistry, Ajman City 346, United Arab Emirates
5. Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, 3010 Bern, Switzerland
6. Dental Health Department, King Saud University College of Applied Medical Sciences, Riyadh 1145, Saudi Arabia
7. Department of Operative Dentistry, University of Iowa College of Dentistry, Iowa City, IA 52242, USA
8. Department of General Dentisry, Creigthon University School of Dentisry, Omaha, NE 68102, USA