Influence of smear layer on the apical leakage of 1 new and 2 old canal sealers

Abstract

Objective: The purpose of an in vitro dye leakage study was to determine the influence of smear layer on the apical leakage of the root canals obturated by lateral condensation using 3 different root canal sealers. Material and Method: The root canals of 120 extracted human teeth were instrumented by step-back technique with HEDSTRÖM file and irrigated with 2.5 NaOCl. The teeth were divided into 2 experimental groups. In the first group the root canal was treated with 10 ml 17% REDTA and 5.25% NaOCl to remove the smear layer. In the second group the root canal was not pre-treated for the removal of the smear layer. All teeth were obturated by lateral condensation technique using three different root canal sealers: AH-26, RSA-Roeko Seal Automix and Ketac-Endo. The teeth were covered with nail varnish excluding 1 mm on the apex and were immersed in 50% solution of silver nitrate for 6 hours. After this period, the teeth were washed and cut longitudinally for apical leakage analysis. The linear breakthrough of the dye was estimated using binocular magnifying class that magnifies 25 times. Results: The results showed less apical leakage in the first group where smear layer was removed: AH-26 (0.81), RSA (0.86) and Ketac-Endo (1.12) in comparison to the group where smear layer was not removed: AH-26 (0.94), RSA (0.98) and Ketac-Endo (1.32). Statistical evaluation of the results showed no significant difference in the leakage between the groups with and without the smear layer. However, RSA and AH-26 were statistically different from Ketac Endo (p lt 0.001) and among the sealers. Conclusion: Used endodontic sealers allowed leakage to occur, and removal of the smear layer reduced apical leakage.