1. Department of Orthodontics, Public Dental Health Service, Eskilstuna, Sweden
2. Division of Orthodontic and Pediatric Dentistry, Department of Dental Medicine, Karolinska Institute, Huddinge, Sweden
3. Centre for Oral Rehabilitation, Folktandvården Östergötland, Norrköping, Department of Prosthetic Dentistry, Malmö University, Malmö, Sweden