1. Department of Dental Public Health, School of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
2. Department of Periodontology, School of Dental Medicine, Tufts University, Boston, Mass.
3. Department of Oral Health Policy and Epidemiology, School of Dental Medicine, Harvard University Boston, Mass.
4. Department of Periodontics and Implantology, School of Dental Medicine, Stony Brook University, Stony Brook, NY.