1. Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.
2. VIP Dental Service and Geriatric Dentistry, School and Hospital of Stomatology, Peking University, Beijing, China.
3. Department of Endodontics, Chi Mei Medical Center, Liouying, Tainan, Taiwan.
4. Department of Endodontics, School of Dentistry, Hacettepe University, Ankara, Turkey.