Koyu Ono1, Tomoko Goto2. 1. Department of Dentistry and Maxillofacial Surgery, Itoh Dento-Maxillofacial Hospital, 4-14 Kokaihonmachi, Kumamoto, 860-0851, Japan. hoku4koyu3@yahoo.co.jp. 2. Department of Anesthesiology, Itoh Dento-Maxillofacial Hospital, Kumamoto, Japan.