evaluation of apical micro-leakage of different endodontic sealers in the presence and absence of moisture

background and aims. with availability of hydrophilic sealers, drying of the canals before endodontic obturation is still a matter of debate. the aim of this study was to compare the apical micro-leakage of ah26, excite dsc, mta fillapex, and zoe sealers in dry and moist root canals. materials and methods. this experimental study was performed on 90 extracted maxillary central incisors. rotary files were used for preparation of the canals. root canals were filled with a single gutta percha cone, using one of the four seal-ers, under dry and moist root canal conditions (10 teeth in each group). orifices were sealed with glue wax and all root sur-faces were covered with nail polish except the positive control group. after ten days in 100% humidity, teeth were placed in methylene blue, and then were cut in longitudinal axis. blue color permeability was measured by stereomicroscope in mi-crometers. data were analyzed by t-test, anova and scheffe post hoc test using spss v.18 software at p 0.05). apical micro-leakage was significantly higher in the excite dsc groups (p < 0.001). conclusion. ah26 provided the least apical micro-leakage under dry conditions while zoe had the highest micro-leakage under moist conditions. mta fillapex provided acceptable apical seal regardless of moisture. key words: micro-leakage, moisture, root canal therapy, sealer.