1. Oral Medicine and Periodontology Department Faculty of Dentistry, Cairo University CairoEgypt
2. Stem Cell and Tissue Engineering Research Group Faculty of Dentistry, Cairo University Cairo Egypt
3. Clinic for Conservative Dentistry and Periodontology Christian-Albrechts-Universität Kiel Kiel Germany
4. Department of Endodontics Faculty of Dentistry, Cairo University CairoEgypt
5. Department of Operative and Preventive Dentistry Faculty of Dentistry, Cairo University Cairo Egypt
6. Department of Operative and Preventive Dentistry Charité – Universitätsmedizin Berlin Berlin Germany