Statement of Problem: Complete root canal seal is one of the most important aims of root canal treatment. Elimination of smear layer plays an important role in this regard.
Purpose: The purpose of this study was to compare the apical microleakage of Tubliseal sealer when 17% EDTA, 7% citric acid, or 20% citric acid was used to remove the smear layer.
Materials and Method: In this experimental study, 80 single rooted teeth were selected. The crowns were removed from cemento enamel junction (CEJ). Instrumentation of the canal was performed by the step back method. The teeth were randomly divided into 3 experimental groups of 20 and 2 control groups of 10 (positive and negative groups). Final irrigation was implemented as follows: group1; EDTA17%+NaOCl, group2; 7% citric acid + NaOCl and group3; 20% citric acid + NaOCl. Then, the groups were obturated with gutta percha and Tubliseal sealer. Lateral condensation technique was carried out in all groups. The teeth were stored in 100% humidity and 37ºC for 48 hours. The root surfaces other than the apical 2mm were covered with 2 layers of nail polish. After that, the teeth were placed in metylene blue dye for 72 hours. Then, the teeth were sectioned longitudinally with a diamond disk and the degree of dye penetration was measured. The results were statistically analyzed by one-way Variance and Post Hoc Tukey tests.
Results: A statistically significant difference was found between the groups ( p < 0.05). The least amount of dye penetration (2.59mm) was belonged to 17% EDTA group and the highest mean dye penetration occurred in the group in which 20% citric acid was used (3.59mm).
Conclusion: The results of this in vitro study indicates that when a ZOE-based sealer is used for obturation of the root canal system, EDTA is recommended to remove the smear layer. Furthermore, it can be concluded that the main purpose of removing the smear layer is not only to clean the dentinal tubules from organic and inorganic debris, but also to create a dentinal surface structure that best fits the characteristics of the sealer used for root canal obturation.