1. Department of Periodontics University of Washington School of Dentistry Seattle Washington USA
2. Department of Advanced Oral Sciences and Therapeutics University of Maryland School of Dentistry Baltimore Maryland USA
3. Division of Clinical Dentistry University of Detroit Mercy School of Dentistry Detroit Michigan USA
4. Institute of Epidemiology and Preventive Medicine College of Public Health, National Taiwan University Taipei Taiwan
5. Department of Periodontics and Dental Hygiene University of Texas Health Science Center at Houston Houston Texas USA