1. Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Japan
2. Prosthodontic Department, Faculty of Dentistry, Tanta University, Tanta, Egypt
3. Department of Civil and Environmental Engineering, Tohoku University Graduate School of Engineering, Sendai, Japan
4. Department of Electrical and Electronic Engineering, National Institute of Technology, Oita College, Oita, Japan
5. Tohoku University Graduate School of Dentistry, Sendai, Japan