Bacterial penetration along different root canal fillings in the presence or absence of smear layer in primary teeth

To study the effect of the smear layer on the penetration of bacteria along different root canal fillings and to compare the sealing ability of new endodontic material Apexit plus as compared to Zinc Oxide Eugenol (ZOE) in primary teeth.

A total of 60 human root segments were instrumented for endodontic treatment. Half of the sample size was irrigated with normal saline and in other half 3% NaOCl, 3% H2O2 and 17% EDTA was used alternatively as irrigant during instrumentation. The roots were rinsed thoroughly with distilled water and sterilized by autoclaving for 20 min at 121 +/- 2 degrees C. Roots with and without smear layer were obturated with Apexit plus, Zinc oxide eugenol. Following storage in humid conditions at 37 degrees C for 2 days, the specimens were mounted into a bacterial leakage test model for 180 days.

At 180 days, there is statistically significant difference with a P value of < 0.05 among all groups except ZOE-smear and -nonsmear. In the presence of smear layer Apexit plus demonstrated more leakage. No leakage was observed in ZOE groups. ZOE demonstrated better sealing ability than Apexit plus.

Removal of smear layer helps in better resistance to bacterial penetration along Apexit plus root canal fillings but no effect is seen along ZOE root canal fillings.