1. Department of Forensic Dentistry, Osaka Dental University, Osaka 573-1121, Japan
2. Department of Innovation in Dental Education, Osaka Dental University, Osaka 573-1121, Japan
3. Department of Chemistry, Osaka Dental University, Osaka 573-1121, Japan
4. Department of Pharmacology, Matsumoto Dental University, Nagano 399-0781, Japan