1. Department of Dental Anesthesiology, Kyushu University Hospital, Fukuoka 819-0395, Japan
2. Department of Clinical Engineering, Faculty of Health Care, Jikei University of Health Care Sciences, Osaka 532-0003, Japan
3. Graduate School of Engineering, Osaka Metropolitan University, Osaka 558-8585, Japan
4. Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
5. Department of Clinical Engineering, Shikoku Central Hospital of the Mutual Aid Association of Public School Teachers, Ehime 799-0193, Japan
6. Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan