1. Department of Pathophysiology‐Periodontal Science Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences 2‐5‐1 Shikata‐cho Kita‐ku Okayama 700‐8525 Japan
2. Department of General Medicine Okayama University Hospital 2‐5‐1 Shikata‐cho Kita‐ku Okayama 700‐8558 Japan
3. Department of Oral Rehabilitation and Regenerative Medicine Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences 2‐5‐1 Shikata‐cho Kita‐ku Okayama 700‐8525 Japan