1. Substitutive Dental Sciences Department, College of Dentistry, Taibah University, Madina, Saudi Arabia
2. Removable Peosthodontic Department, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt
3. Prosthodontic Department, Mouwsat Hospital, Medina, Saudi Arabia
4. Oral Medicine, Periodontology, Oral Diagnosis and Radiology Department, Faculty of Dentistry, Tanta University, Tanta, Egypt
5. Periodontology and Preventive Dental Science Department, College of Dentistry, Taibah University, Madina, Saudi Arabia
6. Removable Prosthodontic Department, College of Dentistry, Future University, Cairo, Egypt