1. Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
2. Department of Orthodontics and Pediatric Dentistry, Hamdan Bin Mohammed College of Dental Medicine (HBMCDM), Mohammed Bin Rashid University of Medicine and Health Sciences (MBRU), Dubai, UAE
3. Private Clinic, Cologne, Germany
4. Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia