1. Department of Oral Oncology, Oral and Maxillofacial surgery Tokyo Dental College Chiba Japan
2. Division of Surgical Pathology, Ichikawa General Hospital Tokyo Dental College Chiba Japan
3. Oral Cancer Center Tokyo Dental College Chiba Japan
4. Department of Oral Rehabilitation and Maxillofacial Surgery, Narita Hospital International University of Health and Welfare Chiba Japan