1. Department of Prosthodontics, Gerodontology and Oral Rehabilitation Osaka University Graduate School of Dentistry 1‐8 Yamada‐Oka Suita Osaka 565‐0871 Japan
2. Division of Comprehensive Prosthodontics Niigata University Graduate School of Medical and Dental Sciences 8050, Ikarashi 2‐no‐cho Niigata 950‐2181 Japan
3. Osaka University 1‐1 Yamadaoka Suita Osaka 565‐0871 Japan
4. Department of Preventive Cardiology National Cerebral and Cardiovascular Center 5‐7‐1, Fujishiro‐dai Suita Osaka 565‐8565 Japan