1. Department of Orthodontics Dental Clinic Faculty of Medicine University of Niš Zorana Ðinđića 81 18000 Niš Serbia
2. Department of Chemistry Faculty of Sciences and Mathematics University of Niš Višegradska 33 18000 Niš Serbia
3. Department of Biology and Ecology Faculty of Sciences and Mathematics University of Niš Višegradska 33 18000 Niš Serbia
4. Department of Oral Medicine and Periodontology Faculty of Medicine University of Niš Zorana Ðinđića 81 18000 Niš Serbia
5. Department of Physiology Faculty of Medicine University of Niš Zorana Ðinđića 81 Niš 18000 Serbia