1. Department of Restorative Dental Sciences, King Saud University, P.O. Box 68004, Riyadh 11527, Saudi Arabia
2. Dental Department, Ministry of Health, Riyadh, Saudi Arabia
3. Dental Department, Prince Sattam University, Al-Kharj, Saudi Arabia
4. Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, P.O. Box 68004, Riyadh 11527, Saudi Arabia