1. Research associate, Eng A B Growth Factors and Bone Regeneration Research Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia;
2. assistant professor, Eng A B Growth Factors and Bone Regeneration Research Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia;
3. associate professor, Division of Periodontology, School of Dental Medicine, University of Connecticut, Farmington, CT, USA;
4. professor, Eastman Institute for Oral Health, Division of Periodontology, University of Rochester, Rochester, NY, USA