assessment of apical microleakage in root canal treated teeth with or without apical patency

introduction: the effect of apical patency on apical seal is very important in canal preparation. the effect of apical patency on seal of this area was evaluated in this study. methods and materials: in this experimental in vitro study, 90 single rooted mature intact human teeth were cut at cej and were divided in two test groups with 40 each and two control groups with 5 each. canal preparation was done by step back technique; without patency file in group 1 and with patency file in group 2. then the canals were obturated by lateral condensation. no instrumentation or obturation was done on control groups. the root surfaces of two test groups and positive control group were covered with one layer of adhesive wax and two layers of nail varnish except for apical 2mm. then they were placed in black ink at 37ºc in an incubator for 5 days. thereafter the roots were split into halves and leakage of dye was measured by a stereomicroscope. the data was analyzed by t-student test. results: mean dye penetration was 10: 125 mm in group 1 and 6, 3 mm in group 2. this difference was statistic-cally significant. conclusion: apical seal could be increased with the maintenance of apical patency during canal preparation.