1. Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
2. Dental Center, King Saud Medical City, Riyadh, Saudi Arabia.
3. Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
4. Warwick Dentistry, Warwick Medical School, University Of Warwick, Warwick, United Kingdom.