1. Department of Oral Anatomy and Cell Biology, Kyushu Dental College, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu, Japan, 803-8580;
2. Section of Oral and Maxillofacial Oncology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan, 812-8582;
3. Department of Operative Dentistry and Endodontics, Kanagawa Dental College, 82, Inaoka-cho, Yokosuka, Japan, 238-8580; and
4. Department of Oral Biology, Hiroshima University, Graduate School of Biomedical Science, Kasumi 1-2-3, Minami-ku, Hiroshima, Japan, 734-8553;