1. Department of Prosthodontics; Gerodontology and Oral Rehabilitation; Osaka University Graduate School of Dentistry; Osaka Japan
2. Shitennoji-Yawaragien Welfare Facility for the Disabled; Tondabayashi Osaka Japan
3. Slowlife Yao Long-term Care Health Facility; Yao Osaka Japan
4. Clover-no-Oka Long-term Care Health Facility; Kawachinagano Osaka Japan
5. Ikurien-Naka Special Elderly Nursing Home; Sugaya Naka Ibaragi Japan
6. Department of Social and Preventive Epidemiology; School of Public Health; The University of Tokyo; Bunkyo Tokyo Japan