1. Department of Prosthodontics The University of Iowa College of Dentistry and Dental Clinics Iowa City Iowa USA
2. Clinical Sciences Department, College of Dentistry Ajman University Ajman City UAE
3. Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine University of Bern Bern Switzerland
4. A.T. Still University Arizona School of Dentistry and Oral Health Mesa Arizona USA
5. Department of Dental Health, College of Applied Medical Sciences King Saud University Riyadh Saudi Arabia