1. Faculty of Medicine, Department of Periodontology, Kragujevac
2. University of Travnik, Faculty of Pharmacy and Health, Department of Dentistry, Travnik, Bosnia and Herzegovina
3. Faculty of Medicine, Department of Periodontology, Kragujevac + Faculty of Dentistry, Clinic of Periodontology and Oral Medicine, Pančevo
4. Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Belgrade, Serbia