Effect of various mixing ratios on antibacterial properties and hardness of endodontic sealers

Most chemically cured two-component dental materials, including endodontic sealers, are marketed with mixing instructions but with no strict mixing ra tios. The present study evaluated the antibacterial properties and hardness of three endodontic sealers: Roth's cement (RC), CRCS, and AH26, mixed to four controlled consistencies within the range of the manufacturer recommen dations. Using Enterococcus faecalis as the test microorganism, antibacteri al activity was evaluated by agar diffusion and direct contact test. Surfac e hardness of sealers with the same consistency was evaluated on week-old s pecimens by the Knoop Hardness Number tester. In the agar diffusion test, l ight consistency of RC showed larger zones of inhibition than heavier consi stency, whereas no significant differences were found with AH26 or CRCS. in the direct contact test, RC and CRCS exhibited complete inhibition of bact erial growth at all consistencies, whereas AI 126 with the heavier consiste ncies did not inhibit bacterial growth at 24 h samples. The hardness of AH2 6 and CRCS was significantly lower with lighter consistencies. It is conclu ded that endodontic sealers possess different antibacterial and physical pr operties according to their mixing consistencies.