The effect of smear layer removal on apical seal of teeth obturated with two different obturation techniques

Background and objectives: .The purpose of this study was to evaluate the effect of smear layer removal on apical seal and the quantity of microleakage associated with lateral cold condensation and thermafil obturation. Methods: Forty extracted single–rooted human teeth were randomly divided into two experimental groups; in group A, 20 roots with smear layer free, 5.25 % sodium hypochlorite (NaOCl) and 17% Ethylenediamine tetraacetic acid (EDTA) were used as irrigants to remove the smear layer, while in group B, 20 roots with smear layer, normal saline was used as irrigant. All root canals were instrumented with the Pro-taper rotary system using a crown-down technique. Each group of instrumented roots were subdivided randomly into two obturation groups; in group 1, 10 roots were obturated by thermafil with plastic carrier, while in group 2, 10 roots were obturated by cold lateral compaction technique. Zinc oxide euginol was used as the sealer. The root surfaces were then coated with nail polish except for the apex, then dye penetration study conducted and samples were examined under the stereomicroscope. Data had been collected from two independent examiners and statistically analyzed using student t-test. Results: There was non significant difference between all the groups radiographically while stereomicroscopic analysis showed significant difference of smear layer free group when obturated by thermafil with other groups. Conclusion: Smear layer free group gave the best results when used with lateral condensation technique (LCT) and smear layer group gave the best results when used with thermafil.