1. Division of Oral Medicine and Pathology Department of Human Biology and Pathophysiology School of Dentistry Health Sciences University of Hokkaido Hokkaido Japan
2. Division of Periodontology and Endodontology Department of Oral Rehabilitation School of Dentistry Health Sciences University of Hokkaido Hokkaido Japan
3. Division of Disease Control and Molecular Epidemiology Department of Oral Growth and Development School of Dentistry Health Sciences University of Hokkaido Hokkaido Japan
4. Department of Psychosomatic Dentistry Graduate School of Medical and Dental Sciences Tokyo Medical and Dental University Tokyo Japan