Masanori Tsukamoto1, Jun Hirokawa2, Takeshi Yokoyama3. 1. Department of Dental Anesthesiology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. tsukamoto@dent.kyushu-u.ac.jp. 2. Department of Dental Anesthesiology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. 3. Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.