1. Department of Periodontics and Preventive Dentistry, School of Dental Medicine, University of Pittsburgh
2. Department of Periodontics, Ondokuz Mayis University School of Dental Medicine, Kurupelit, Samsun, Turkey
3. Departments of Oral Biology, Pediatric Dentistry and Center for Craniofacial and Dental Genetics, School of Dental Medicine, and Department of Human Genetics, Graduate School of Public Health, and Clinical and Translational Science Institute, University of Pittsburgh, 614 Salk Hall, 3501 Terrace St., Pittsburgh, PA 15261, USA