1. Crown and Bridge Prosthodontics, Department of Oral Functional Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Hokkaido 060‑8586, Japan
2. Department of Oral Disease Research, National Center for Geriatrics and Gerontology, Obu, Aichi 474‑8511, Japan
3. Biochemistry and Molecular Biology, Department of Oral Health Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Hokkaido 060‑8586, Japan