1. Department of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University, Riyadh, Saudi Arabia;
2. Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Aden University, Aden, Yemen;
3. American Board of Endodontics, Chicago, IL, USA;
4. American Board of Periodontology, Severna Park, MA, USA;
5. Department of Periodontics and Community Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia