1. Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
2. Faculty of Dentistry, Nguyen Tat Thanh University, Ho Chi Minh City 700000, Vietnam
3. Dental Hospital, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand
4. Department of Implant Dentistry, School of Dentistry, Showa University, Tokyo 145-8515, Japan
5. Digital Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan