1. Section of Oral and Diagnostic Sciences, Division of Endodontics, College of Dental Medicine, Columbia University, New York, New York.
2. Department of Endodontics, Prosthodontics, and Operative Dentistry, College of Dental Surgery, Dental School, University of Maryland, Baltimore, Maryland.
3. Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
4. Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, Los Angeles, California.
5. Department of Chemical and Biological Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois.