Methods: In this experimental study, 64 extracted human teeth were decoronated to a standardized length of 16 mm and instrumented with protaper rotary system according to manufacturer's instructions. The teeth were randomly divided into 4 experimental (n=14) and 2 control (n=4) groups (+/-).Then, the roots in negative control and experimental were obturated with either Resilon or Gutta-percha alone or with a 2 mm glass ionomer intraorifice barrier. In the negative control groups, all teeth surfaces were coated with 2 layers of nail polish. In the positive control groups, canals were not obturated. After setting of the sealers, microleakage was evaluated with microbial analysis. Data were evaluated with chi-square test one-way analysis of variance and Tukey.
Results: Positive control leaked within 24 hours, whereas none of the negative control leaked. Resilon and gutta-percha with intraorifice barrier showed less leakage than Resilon and Gutta-percha without any barrier, although the difference was not statistically significant (P>0.05).
Conclusions: Under conditions of this study, all 4 groups showed leakage in some specimens, but Glass ionomer might be an effective intraorifice barrier.