1. Clinic of Periodontology and Oral Medicine, School of Dentistry, University of Belgrade, Dr Subotica 8, 11000, Belgrade, Serbia;
2. School of Dentistry, Queen’s University Belfast, Royal Victoria Hospital, Grosvenor Road, Belfast, Northern Ireland, UK;
3. Clinics of Gastroenterology and Hepatology, Clinical Centre Zvezdara, Belgrade, Serbia; and
4. Institute of Molecular Biology and Human Genetics, School of Dentistry, University of Belgrade, Serbia