1. Department of Dental Public Health, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
2. Department of Health Policy and Health Services Research, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
3. Biostatistics, School of Public Health, Boston University, Boston, MA, USA
4. The University of Sydney School of Dentistry, Westmead, Australia