The aim of the present study was to compare bond strength and apical seal obtained in root canals prepared with a new rotary system (Endo-Eze) and obturated with two different techniques (AH Plus sealer/ gutta-percha points and EndoREZ sealer/ EndoREZ points). Sixty freshly extracted mandibular first molars were used in this study. The distal root of each collected tooth was removed by tapered diamond stone mounted in high-speed handpiece. Mesio-buccal canals of teeth were cleaned and shaped by Endo-Eze system, then they were classified into two main groups of 30 each according
to obturation materials used, Group (1): canals were obturated with lateral condensation using AH-Plus sealer and gutta-percha and Group (2): canals were obturated with lateral condensation using Endo-REZ sealer and Endo-REZ points. Within each group, samples were divided into 2 subgroups of 15 each according to assessment method, subgroup (A): 15 teeth were used for assessment of microleakage and subgroup (B): 15 teeth were used for assessment of push-out bond strength. Subgroup (C): 15 teeth were used for assessment of microleakage and subgroup (D): 15 teeth were used for assessment of push-out bond strength. Then subgroups A & C were further divided into 3 divisions according to storage time (immediately, one month and three months) after setting of the sealer. Assessment of microleakage was done by dye penetration test where 2 layers of nail varnish were applied to all the root surfaces except the apical 2 mm, then
the apices of the teeth were immersed in 2 % methylene blue dye solution for 2 days. Examination for linear dye penetration was done using stereomicroscope. Assessment of bond strength was done by push-out test where compressive load was applied apicocoronally in order to push the filling material toward the larger diameter. The results
regarding the microleakage showed that the immediate observation period in (AH Plus / gutta-percha) recorded the highest statistically significant leakage mean value while the lowest mean value was recorded in the 3 months observation period of Endo-Rez / Endo-Rez points. Regarding the push out bond strength, it was found that AH Plus /