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Original Research

Open Access

Smear layer removal efficacy of irrigating solutions applied distinct needle designs: a scanning electron microscopy study

  • Akif Demirel1,*,
  • Nur Sena Önder1
  • Merve Alkış2
  • Şaziye Sarı1

1Department of Pediatric Dentistry, Faculty of Dentistry, Ankara University, 06560, Ankara, Turkey

2Department of Pediatric Dentistry, Faculty of Dentistry, Uşak University, 64000, Uşak, Turkey

DOI: 10.22514/jocpd.2022.016

Submitted: 08 September 2022 Accepted: 20 October 2022

Online publish date: 10 November 2022

*Corresponding Author(s): Akif Demirel E-mail:


This research aimed to assess the efficacy of different irrigants applied with different types of needle tips on smear layer removal (SLR) in primary incisors. This study was carried out with 35 freshly extracted upper primary incisors. The samples were randomly distributed to five study groups (n = 7) (1 to 4: experimental, 5: control). These included Group 1: 5% Ethylenediaminetetraacetic Acid (EDTA) + 1% Sodium Hypochlorite (NaOCl) applied with open-ended needle (OEN), Group 2: 6% Citric Acid (CA) + 1%NaOCl applied with OEN, Group 3: 5% EDTA + 1% NaOCl applied with double side-vented needle (DSVN), Group 4: 6% CA + 1% NaOCl applied with DSVN and Group 5: 1% NaOCl applied with OEN. Accordingly, the inner root surfaces were examined using scanning electron microscopy (SEM). The differences between the groups were analyzed using Kruskal-Wallis, Friedman and Siegel-Castellan tests (p < 0.05). In the coronal third, all the experimental groups (groups 1, 2, 3 and 4) were superior to the control group (p = 0.002, p = 0.002, p < 0.001 and p < 0.001, respectively). Groups 2, 3 and 4 showed superior SLR to the control group (p = 0.024, p = 0.001 and p = 0.004, respectively) in the middle third. DSVN groups of EDTA and CA showed superior SLR efficacy than the control (p < 0.001 and p = 0.002, respectively) in the apical third. The SLR efficacy was higher in the coronal third compared to the apical third in the experimental groups (groups 1, 2, 3 and 4) (p = 0.015, p = 0.048, p = 0.048 and p = 0.048, respectively). In addition, 3 samples of EDTA showed erosion (2 in the coronal with OEN, 1 in the middle with DSVN). It was possible to conclude that the SLR efficacy of DSVNs and OENs was similar. CA could be recommended since it did not cause erosive damage compared to EDTA in primary incisors.


Citric acid; EDTA; Irrigation; Primary teeth; Pulpectomy; Side-vented needle

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Akif Demirel,Nur Sena Önder,Merve Alkış,Şaziye Sarı. Smear layer removal efficacy of irrigating solutions applied distinct needle designs: a scanning electron microscopy study. Journal of Clinical Pediatric Dentistry. 2022.doi:10.22514/jocpd.2022.016.


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