1. Department of Dentistry, Division of Endodontics, Prince Sultan Military Medical City, P.O. Box 7897, Riyadh 11159, Saudi Arabia
2. Department of Dentistry, Division of Periodontics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
3. Department of Dentistry, Division of Orthodontics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
4. Department of Dentistry, Division of Endodontics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia