1. Department of Population and Quantitative Health Sciences, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
2. Department of Preventive Dental Science, College of Dentistry, King Saud Bin Abdelaziz University for Health Sciences, Riyadh, Saudi Arabia
3. King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
4. Department of Periodontics, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio, USA