1. Department of Pediatric Dentistry and Preclinical Dentistry, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
2. Laser Laboratory Dental Surgery Department, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
3. Department of Orthodontics, Technische Universitat Dresden, 01307 Dresden, Germany
4. Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw, Poland