comparison of apical microleakage using ni-ti with stainless steel finger spreaders

introduction: the purpose of this in vitro study was to compare apical microleakage after obturation with nickel-titanium (niti) compared to stainless steel (ss) finger spreaders. materials and methods: eighty straight single-rooted human teeth were instrumented using step-back technique. the specimens were randomly divided into four groups. the two experimental groups (n=30) and the negative control group (n=10) were obturated by lateral condensation technique with ariadent gutta-percha and ah26 sealer. the roots in the positive control group (n=10) were instrumented but not obturated. in one group, ss and in another group niti spreaders were used. microleakage evaluation was conducted using dye penetration method t-test was used for statistical analysis. results: the results showed statistically significant differences between niti and ss groups (p=0.022), with the greatest dye penetration in ss group and the least in niti group. conclusion: according to the results of the present study using niti spreader decrease apical microleakage in endodontically treated teeth. [iranian endodontic journal 2009;4(4):149-51]