1. Department of Stem Cell Biology and Regenerative Medicine, National Center for Geriatrics and Gerontology, Aichi, Japan.
2. Department of Cariology, Restorative Sciences, Endodontics, University of Michigan, School of Dentistry, Ann Arbor, Michigan.
3. Department of Endodontics, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina.
4. Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.