1. Department of Dental Material Science, Division of Oral Functional Sciences and Rehabilitation, Asahi University School of Dentistry, Mizuho 501-0296, Japan
2. Division of Clinical Cariology and Endodontology, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu 061-0293, Japan
3. Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita 501-0296, Japan
4. The Wakasa Wan Energy Research Center, Tsuruga 914-0192, Japan