1. Unit of Orthodontics and Paediatric Dentistry, Section of Dentistry, Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy
2. Facultad de Odontología, Universidad Autónoma del Estado de México, Toluca, MEX, Mexico
3. Orthodontic Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt
4. Institute of Dentistry, Faculty of Medicine, University of Turku, Turku, Finland