1. Oral and Maxillofacial Surgery, Japan Community Health Care Organization Sendai Hospital, 3-16-1 Tsutsumimachi, Aoba-ku, Sendai 981-8501, Japan
2. Division of Oral and Maxillofacial Surgery, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan