Smear Layer and Sealing Ability of Three Root Canal Sealers

The purpose of this study was to determine the sealing ability of three individual sealers and to compare the sealing ability of these sealers in the presence and absence of smear layer. Total of sixty single rooted mandibular first premolar teeth were used. The crowns were removed at the cementoenamel junction and roots prepared to # 35 K-file. The teeth were randomly divided into two equal groups A and B. The smear layer was removed from group B with EDTA (17%) and NaOCl (5.25%) but it was not removed in group A. Group A was then divided into three sub-groups, A1, A2 and A3. Group B was also divided into three sub-groups, B1, B2 and B3. Each sub-group consisted of 10 specimens. In sub-groups A1 and B1, AH Plus sealer, in sub-groups A2 and B2, Ketac-endo sealer and in sub-groups A3 and B3, Roth sealer was used and obturated with gutta percha using lateral condensation technique. After storage in 100 % humidity at 37°C for one week, the root surfaces were coated with nail polish (except at the apex) and suspended in 2 % methylene blue dye solution for one week. The roots were sectioned logitudinally to determine the following mean levels of dye penetration, A1 -2.675 mm, B1 2.092mm, A2 2.346 mm B2 endo 4.520 mm, A3 4.929 mm, B3 3.372 mm. This study has illustrated that Ketac-Endo sealer provides significantly better seal in the presence of smear layer than in the absence of smear layer. Moreover it gave better seal than Roth 801 sealer in the presence of smear layer.