This study assessed the correlation between leakage from the cervix to the apex and from the apex to the cervix for different post preparation techniques. Sixty roots were obturated with gutta-percha lateral condensation and AH Plus sealer and divided into two groups of 30 roots each. Immediate post preparation was used for one group and delayed preparation was used for the other. Two subgroups of 15 roots each were formed to investigate leakage from cervix-to-apex and from apex-to-cervix. The extent of leakage was determined using a dye, India ink, and a clearing technique that rendered the teeth transparent. Linear measurement of the dye penetration was recorded and examined with a stereomicroscope. Eight teeth were used as positive and negative controls. Leakage was observed in all samples. No statistically significant differences were found between the immediate and delayed post preparation techniques regarding apex-to-cervix leakage; however, the values of cervix-to-apex leakage were significantly lower for the immediate technique than for the delayed technique.
