A fluid transport model study was used to compare the sealing ability of five root canal sealers (AH26, AH Plus, Apexit, Diaket, and Ketac-Endo) on 60 single-rooted teeth after 1 yr of storage. The root canals were prepared with Gates Glidden drills by using a step-back technique before lateral condensation of gutta-percha with the tested sealers. The specimens were stored in saline solution for 1 yr at 37 degrees C. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section. Apexit (0.490 microl) leaked significantly more than AH Plus (0.378 microl) and Ketac-Endo (0.357 microl), whereas AH26 (0.390 microl) and Diaket (0.429 microl) showed no significant difference from either Apexit or from AH Plus and Keto-Endo.