Section of Oral Medicine, MC1605, University of Connecticut Health, 263, Farmington Avenue, Farmington, CT, 06030-1605, USA. Lalla@uchc.edu. Division of Biostatistics, School of Public Health, University of Minnesota, 2221 University Ave SE Suite 200, Minneapolis, MN, 55414, USA. Division of Oral Medicine and Dentistry, Brigham and Women's Hospital, 1620 Tremont Street, 3rd Floor, Boston, MA, 02120, USA. Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, 188 Longwood Avenue, Boston, MA 02115, USA. Department of Oral Medicine, University of Pennsylvania School of Dental Medicine, 240 South 40th Street, Philadelphia, PA, 19104, USA. Department of Oral & Maxillofacial Surgery and Bluestone Center for Clinical Research, New York University College of Dentistry, 421 First Avenue, New York, NY, 10010, USA. Department of Dental Ecology, School of Dentistry, University of North Carolina, Chapel Hill, NC, CB 7450, USA. Department of Oral Medicine, Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC, 28203, USA.