1. Center of Oral Clinical Examination, Hiroshima University Hospital, Japan
2. Department of Periodontal Medicine, Graduate School of Biomedical & Sciences, Hiroshima University, Japan
3. Division of Dental Hygiene, Department of Clinical Practice and Support, Hiroshima University Hospital, Japan
4. Division of Blood Transfusion, Hiroshima University Hospital; 5AIDS Care Unit, Hiroshima University Hospital, Japan