1. Section of Oral and Diagnostic Sciences, Division of Endodontics, College of Dental Medicine, Columbia University, New York, New York.
2. Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, Los Angeles, California.
3. Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, California.
4. Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland.
5. Department of Endodontics, Prosthodontics, and Operative Dentistry, College of Dental Surgery, Dental School, University of Maryland, Baltimore, Maryland.