Maria Rosaria Ricchiuti1, Manuela Mucedero2, Paola Cozza2. 1. Department of Orthodontics, University of Rome Tor Vergata, Viale Oxford, 81, 00133 Rome, Italy. mariarosariar81@libero.it. 2. Department of Orthodontics, University of Rome Tor Vergata, Viale Oxford, 81, 00133 Rome, Italy.