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. 2019 Feb 6;4(1):9-14.
doi: 10.14744/eej.2018.06078. eCollection 2019.

Influence of Apical Preparation Size on Effective Conventional Irrigation in the Apical Third: A Scanning Electron Microscopic Study

Seth Butcher  1 , Abeer Mansour  2 , Mohamed Ibrahim  1   2
Affiliations

Influence of Apical Preparation Size on Effective Conventional Irrigation in the Apical Third: A Scanning Electron Microscopic Study

Seth Butcher et al. Eur Endod J. .

Abstract

Objective: This study aimed to investigate the relationship between final apical preparation size and smear layer removal in the apical third using conventional irrigation in mandibular bicuspids.

Methods: A total of 66 extracted human mandibular bicuspids with comparable root canal morphology were equally divided into five experimental groups and a control group (n=11). Based on their experimental group, samples were instrumented up to size 25, 30, 35, 40, or 45 with 0.04 taper using 2.5% sodium hypochlorite (NaOCl) as the irrigant. Final irrigation was performed with 17% EDTA followed by 2.5% NaOCl. The control group was instrumented up to size 45/.04, and was irrigated with distilled water. Samples were sectioned buc-colingually, and they were qualitatively evaluated under scanning electron microscope for efficacy in smear layer removal. The Kruskal-Wallis and Mann-Whitney U tests were employed for statistical analysis.

Results: Statistical analysis revealed comparable removal of smear layer in the coronal and middle thirds of all experimental samples regardless of grouping. When using file size larger than 35, removal of smear layer in the apical third significantly improved (p<0.05). No significant difference was observed between 40/.04 and 45/.04.

Conclusion: Under the conditions of this study, using conventional irrigation, apical enlargement more than size 35/.04 is essential to enhance removal of smear layer at the apical third.

Keywords: Apical diameter; SEM; conventional irrigation; dentinal tubules; smear layer; sodium hypochlorite.

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Conflict of interest statement

Disclosures Conflict of interest: The authors deny any conflict of interest.

Figures

Figure 1
Figure 1
Scanning electron photomicrographs representative of group 40 (40/04), showing clean root canalat (a) coronal, (b) middle, and (c) apical thirds. Magnification: 1000x
Figure 2
Figure 2
Scanning electron photomicrograph showing presence of debris blocking some dentinal tubules in the apical third 4000x
Figure 3
Figure 3
Scanning electron photomicrographs showing thin smear layer and dentinal tubules partially open at apical thirds of groups 25 (a), 30 (b) & 35 (c). Magnification: 400x
Figure 4
Figure 4
Scanning electron photomicrographs showing total surface covering with thick smear layer in control group in Coronal (a), Middle (b) and Apical (c) thirds. Magnification: 400x
See this image and copyright information in PMC

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