1. Operative Dentistry Department, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
2. Department of Biomaterials Science, Osaka University Graduate School of Dentistry, Osaka, Japan
3. Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan
4. Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Osaka, Japan