1. Department of Conservative Dentistry; Institute of Health Biosciences; The University of Tokushima Graduate School; 3-18-15 Kuramoto-cho Tokushima 770-8504 Japan
2. Department of Oral Microbiology; Institute of Health Biosciences, The University of Tokushima Graduate School; 3-18-15 Kuramoto-cho Tokushima 770-8504 Japan
3. Life Science Products Division; NOF Corporation; 20-3 Ebisu Shibuya-ku Tokyo 150-6019 Japan
4. Life Science Research Laboratory, Life Science Products Division; NOF Corporation; 5-10 Tokodai Tsukuba Ibaraki 300-2635 Japan