1. Department of Prosthodontics, Faculty of Medicine, University of Niš, 18000 Niš, Serbia
2. Department of Pathology, Faculty of Medicine, University of Niš, 18000 Niš, Serbia
3. Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Niš, 18000 Niš, Serbia
4. Faculty of Medicine, University of Niš, 18000 Niš, Serbia