1. Division of Endodontics, Department of Restorative Dental Science, King Saud University College of Dentistry, Riyadh, kingdom of Saudi Arabia.
2. Riyadh Colleges of Dentistry and Pharmacy, College of Dentistry, Riyadh, Kingdom of Saudi Arabia.
3. Royal Clinics for the Custodian of The Two Holy Mosques, Riyadh, Kingdom of Saudi Arabia.
4. Microbiology Lab, King Saud University College of Dentistry, Riyadh, kingdom of Saudi Arabia.