1. Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamada-Oka Suita, Osaka 565-0871, Japan
2. Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-Dori Chuo-Ku, Niigata 951-8514, Japan
3. Division of Endodontics, Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiang Mai University, Suthep Road Tambon Suthep Amphur Mueang Chiang Mai, Chiang Mai 50200, Thailand