1 Department of Biomedical, Odontostomatological Sciences and of Morphological and Functional Images, School of Dentistry, University of Messina, Via Consolare Valeria 1, 98100 Messina, Italy. Electronic address: gisola@unime.it.
2 Department of Orthodontics, University of Genova, Via Balbi 5, 16126 Genova, Italy.
3 Department of Orthodontics, School of Dentistry, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
4 Department of Biomedical, Odontostomatological Sciences and of Morphological and Functional Images, School of Dentistry, University of Messina, Via Consolare Valeria 1, 98100 Messina, Italy.