The purpose of this study was to observe the effect of canal filling on the bacteria left in the dentinal tubules and to compare the sealing ability between Gutta-percha and Resilon. The bovine dentin block models were prepared. E. faecalis was inoculated to dentin blocks and incubated. The dentin blocks were divided into 5 groups.

Group 1 was the negative control. Group 2 was the positive control. Group 3 was filled with ZOE based sealer and Gutta-percha, Group 4 with resin based sealer and Gutta-percha, and Group 5 with resin based sealer and Resilon. After 24 hour, the blocks were incubated at 37℃ for 1, 2, 3 and 4 weeks on BHI agar plates.

The internal dentin portion of the blocks was removed using ISO 027, 029, 031, 035 round burs and the dentin chips were incubated at 37℃ for 24 hour. Following incubation, the optical density of the medium was measured. The data were statistically analysed using repeated measures ANOVA and one-way ANOVA.

The results were as follows,

1. There was statistically significant reduction in the number of E. faecalis of the group where dentinal tubules were completely sealed with nail varnish in comparison with the groups obturated with gutta-percha or resilon (p < 0.05).

2. In group 5, the number of E. faecalis in the dentinal tubules decreased significantly with time (p < 0.05), whereas in Group 3 and 4, there was no reduction in its number (p > 0.05).

3. Under the conditions of this experiment, E. faecalis survived up to 4 weeks after obturation with gutta-percha or resilon (p > 0.05).