1. Division of Comprehensive prosthodontics, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
2. College of Dentistry, Manila Central University, Caloocan, Philippines
3. Department of Dentistry, Centro Escolar University, Manila 1000, Philippines
4. Department of Geriatric Dentistry, Osaka Dental University, Osaka, Japan