Advances in Clinical and Experimental Medicine

Title abbreviation: Adv Clin Exp Med
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ISSN 1899–5276 (print)
ISSN 2451-2680 (online)
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Advances in Clinical and Experimental Medicine

2020, vol. 29, nr 2, February, p. 209–213

doi: 10.17219/acem/112603

Publication type: original article

Language: English

License: Creative Commons Attribution 3.0 Unported (CC BY 3.0)

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The effects of alternate irrigation of root canals with chelating agents and sodium hypochlorite on the effectiveness of smear layer removal

Wojciech Wilkoński1,A,B,C,D, Lidia Jamróz-Wilkońska2,A,C,D, Szczepan Zapotoczny3,B,C, Janusz Opiła4,B,C, Jerzy Krupiński5,E,F, Jolanta Pytko-Polończyk6,A,E,F

1 Research Department of the Polish Endodontic Society, Kielce, Poland

2 Private dental office, Wadowice, Poland

3 Department of Physical Chemistry and Electrochemistry, Jagiellonian University, Kraków, Poland

4 Department of Applied Computer Science Faculty of Management, AGH University of Science and Technology, Kraków, Poland

5 Retired Professor of the Medical University of Silesia, Katowice, Poland

6 Department of Integrated Dentistry, Dental Institute, Faculty of Medicine, Jagiellonian University Medical College, Kraków, Poland


Background. After the mechanical preparation of a root canal, the canal walls are covered with a smear layer. In order to deeply clean the dentinal tubules, removal of the smear layer is recommended. There is no consensus on the length of time of rinsing with chelating agents or irrigation with alternating chelating agents and sodium hypochlorite (NaOCl).
Objectives. The aim of the study was to evaluate the effectiveness of smear layer removal using 4 irrigation protocols.
Material and Methods. We prepared 42 straight root canals to size ISO40/04 and assigned them into 4 study groups (n = 10) and a control group (n = 2). The root canals were irrigated as follows: in the control group, 180 s with 5.25% NaOCl; in group 1, 60 s with 40% citric acid (CA) and 120 s with NaOCl; in group 2, 120 s with CA and 120 s with NaOCl; in group 3, 30 s CA, 30 s with NaOCl, 30 s CA and 120 s with NaOCl; and in group 4, 60 s with CA, 30 s with NaOCl, 60 s with CA, and 120 s with NaOCl. The roots were split longitudinally and the root canals were observed under ×200–500 magnification. The root canal walls were analyzed in areas 2 mm, 6 mm and 10 mm from the apex.
Results. In the apical and medial sections, the best effects were achieved in groups 3 and 4. In coronal sections, no significant differences between experimental groups were found.
Conclusion. Within the limitations of this study, it can be concluded that irrigation with alternating NaOCl and CA was the most effective at smear layer removal, regardless of the irrigation time.

Key words

irrigation, citric acid, sodium hypochlorite, smear layer, root canals

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