1. Dental Implant Research Centre, Dentistry Research Institute and Department of Prosthodontics, Faculty of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
2. School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
3. Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
4. Division of Periodontology, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, Mass.