1 Division of orthodontics, faculty of dentistry, Beirut Arab university, Beirut, Lebanon. Electronic address: yassir.talal@gmail.com.
2 Division of orthodontics, faculty of dentistry, Beirut Arab university, Beirut, Lebanon; Department of orthodontics and dentofacial orthopedics, Henry M. Goldman School of Dental Medicine, Boston University, Boston, USA; Department of orthodontics, School of Dental Medicine, Joseph University, Beyrouth, Lebanon.
3 Division of oral health and society, faculty of dentistry, McGill university, Montréal, Canada.
4 Department of developmental sciences, division of orthodontics, faculty of dentistry, Beirut Arab university, Beyrouth, Lebanon.