1. Department of Prosthodontics, Gerodontology and Oral Rehabilitation; Osaka University Graduate School of Dentistry; Osaka Japan
2. Department of Periodontics; Osaka University Graduate School of Dentistry; Osaka Japan
3. Department of Clinical Thanatology and Geriatric Behavioral Science; Osaka University; Graduate School of Human Sciences; Osaka Japan
4. Division of Health Science; Osaka University Graduate School of Medicine; Osaka Japan
5. Division of Social and Human Sciences; Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology; Tokyo Japan
6. Department of Geriatric Medicine; Keio University; School of Medicine; Tokyo Japan