1. Dental School, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
2. Department of Oral Health Science, Division of Orofacial Pain, College of Dentistry, University of Kentucky, Lexington, KY, USA
3. Orthodontics, Division of Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR