1. Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, 1011 North University Ave, Ann Arbor, MI 48109, USA
2. University of Michigan Rogel Cancer Center, 1600 Huron Pathway, Ann Arbor, MI 48105, USA
3. Department of Oral and Maxillofacial Surgical Oncology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
4. Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4, Sakamoto, Nagasaki 852-8523, Japan
5. Department of Oral Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan