1. Departments of Orthodontics,
2. Oral Anatomy and Cell Biology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; and
3. Department of Oral Anatomy, Kyushu Dental College 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan;