Introduction Materials used for root canal obturation and root perforation are expected to have, in addition to preventing apical, lateral and coronary leakage, antimicrobial effects on microorganisms that are not accessible to chemomechanical instrumentation and intra-canal medications. The aim of this study was to evaluate the antimicrobial effect of a novel calcium aluminate-based endodontic nanostructured biomaterial (ALBO-MCCA) using agar diffusion test. Material and methods the two materials were tested in the study. The nanostructured calcium aluminate was synthesized by the hydrothermal sol-gel method from individual components of calcium aluminate (CaOxAl2 O3 ), calcite (CaCO3 ) and barium sulfate (BaSO4 ) as radiocontrast agent in the ratio of 2:2:1 according to V. Jokanovic's recipe. The other used material was calcium silicate MTA Angelus (Londrina, Brazil). The antimicrobial effect was assessed using agar diffusion test. Standard strains of Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, cultured on blood Mueller-Hinton agar and Candida albicans cultivated on Sabouraud Dextrose Agar, were used as test microorganisms. Results the best antimicrobial effect after 24 h both materials showed against S. aureus. The mean values of the growth inhibition zone for ALBO MCCA were 5.7 ± 0.25 mm and MTA 6.2 ± 0.4 mm. The ALBO MCCA material showed slightly stronger antibacterial effect against E. coli compared to MTA (p lt 0.05), whereas none of the materials showed antibacterial effect against E. faecalis. Conclusion the ALBO MCCA material showed certain antibacterial effect on Escherichia coli, Staphylococcus aureus and Candida albicans that was comparable to antibacterial effect of MTA.Uvod Od materijala koji se koriste za opturaciju kanala korena i perforacija na korenu se očekuje da pored sprečavanja apikalnog, lateralnog i koronarnog curenja, poseduju i antimikrobno delovanje na mikroorganizme, koji nisu dostupni hemomehaničkoj obradi i intrakanalnim medikamentima. Cilj ovog istraživanja je bio da se testom difuzije u agaru proceni antimikrobni efekat novog endodontskog nanostrukturnog biomaterijala na bazi kalcijum-aluminata (ALBO-MCCA). Materijal i metode U istraživanju su korišćena dva materijala. Nanostrukturni kalcijum-aluminat je sintetisan hidrotermalnom sol-gel metodom od pojedinačnih komponenata kalcijum-aluminata (CaO·Al2 O3 ), kalcita (CaCO3 ) i barijum-sulfata (BaSO4 ) kao rendgen-kontrastnog sredstva u odnosu 2 : 2 : 1 prema recepturi V. Jokanovića. Drugi korišćeni materijal je kalcijum-silikatni MTA Angelus (Londrina, Brazil). Antimikrobni efekat je ispitivan testom difuzije u agaru. Kao test mikroorganizmi korišćeni su standardni sojevi Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, koji su kultivisani na krvnom agaru MuellerHinton, dok je C. albicans kultivisana na agaru Sabouraud Dextrose. Rezultati Najbolji antimikrobni efekat nakon 24 h oba materijala su pokazala prema bakteriji S. aureus. Izmerene prosečne vrednosti zone inhibicije rasta iznosile su kod ALBO-MCCA (5,7 ± 0,25 mm), odnosno kod MTA (6,2 ± 0,4 mm). Materijal ALBO-MCCA je pokazao nešto veći antibakterijski efekat prema bakteriji E. coli u odnosu na MTA (p lt 0,05), dok prema bakteriji E. faecalis nijedan materijal nije ispoljio antibakterijski efekat. Zaključak Materijal ALBO-MCCA je ispoljio određeni antibakterijski efekat na bakterije Escherichia coli, Staphylococcus aureus i Candida albicans komparabilan sa antibakterijskim efektom MTA