1. Tsukuba Health‐Care Dental Clinic Tsukuba Japan
2. Department of Periodontology Tokyo Medical and Dental University Bunkyo‐ku Japan
3. Department of Oral Interdisciplinary Medicine Kanagawa Dental University Yokosuka Japan
4. Department of Maxillofacial Surgery Tokyo Medical and Dental University Bunkyo‐ku Japan
5. Department of Periodontology Osaka Dental University Hirakata Japan
6. Oral Care Perio Center, Southern Tohoku General Hospital Southern Tohoku Research Institute for Neuroscience Koriyama Japan