Comparative Evaluation of Smear Layer Removal in Apical Third Using Four Different Irrigants With Ultrasonic Agitation: An In Vitro Scanning Electron Microscopy (SEM) Analysis.

Kalaiarasi Murugesan,Sangita Ilango,Sadasiva Kadandale,Sankar Vishwanath,Yashini Thanikachalam,Revathy Parthasarathy

doi:10.7759/cureus.23142

Abstract

AimThis study aims to compare and evaluate the efficacy of four different irrigating solutions like sodium hypochlorite, ethylenediaminetetraacetic (EDTA), Oxum, and ozonated water with ultrasonic agitation in removing the smear layer in the apical third of root canals using Scanning Electron Microscopy (SEM).Materials and methodsFor the study, 50 freshly extracted human mandibular premolars with single well-developed roots without any curvatures were taken. The teeth taken were decoronated to obtain a uniform working length of 15 mm, and the samples were instrumented using a ProTaper Gold rotary file system (Dentsply Maillefer, Ballaigues, Switzerland) up to F2 size, along with irrigation of 1 ml of 3% sodium hypochlorite (NaOCl) in between instrumentation. The samples were randomly divided into five groups with 10 samples each, according to the final irrigant used. Group I-EDTA 17%, Group II-NaOCl 5%, Group III-Oxum, Group IV-ozonated water, and Group V-normal saline. In all groups, ultrasonic agitation of the irrigating solution was performed using a size 20 file, held passively inside the root canal. Then the samples were flushed with distilled water, dried with paper points, split into two halves, and subjected to SEM analysis. SEM images of the apical third region of root samples were taken at 5000X resolution and scored on a scale of 1 to 4.ResultsStatistical analysis was done using one-way ANOVA followed by Tukey’s post hoc test using software version SPSS software version 17.0 (SPSS Inc., Chicago). The results showed that the 17% EDTA group showed the least smear layer scores when compared to other groups with statistical significance. This was followed by the Oxum group and 5% NaOCl group, whereas the ozone water group and saline control group showed the highest smear layer scores.ConclusionThe present study reveals that the EDTA is the superior irrigant in the elimination of smear layer in root canal treatment. Newer irrigants, such as Oxum, can be used as an alternative to EDTA for smear layer removal while remaining biocompatible with dentin. Whereas ozone can be combined with other irrigants for synergistic action of enhanced antimicrobial property and smear layer elimination in the future.

Highlights

The smear layer, which is incarnated by the instrumentation process, is found to contain organic and inorganic materials like the odontoblastic process, pulp tissue debris, bacteria, and blood cells [1]
The results showed that the 17% EDTA group showed the least smear layer scores when compared to other groups with statistical significance
This was followed by the Oxum group and 5% NaOCl group, whereas the ozone water group and saline control group showed the highest smear layer scores

Summary

Introduction

The smear layer, which is incarnated by the instrumentation process, is found to contain organic and inorganic materials like the odontoblastic process, pulp tissue debris, bacteria, and blood cells [1]. When dentin is cut either by rotary or hand instruments [2,3], the mineralized tissues get crippled to produce a hefty amount of debris, which is made up of a mineralized collagen matrix that spreads over the surface of the dentin to form a smear layer. In order to achieve successful root canal treatment, proper biomechanical preparation, irrigation, disinfection, and obturation are mandatory [4]. The presence of the smear layer was found to have a nocent effect, as it prevents the penetration of the irrigants and intracanal medicaments into dentinal tubules [5]. Albeit the effect of removing the smear layer on an effective root canal treatment is still debatable, it

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