SMEAR LAYER REDUCTION IN ROOT CANALS PREPARED WITH TRIANGULAR AND RECTANGULAR FILES AS EVALUATED BY SCANNING ELECTRON MICROSCOPY

Meita Herisa,Noni Maharani,Kamizar Nazar,Dewa Ayu Nyoman Putri Artiningsih,Ratna Meidyawati

doi:10.22159/ijap.2020.v12s2.op-21

Meita Herisa, Noni Maharani + Show 3 more

Open Access

https://doi.org/10.22159/ijap.2020.v12s2.op-21

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Abstract

Objective: Root canal preparation procedures can produce a smear layer when in contact with the root canal wall, which can result in treatmentfailure. As such, the cross-section shape of the file may influence the production of smear layer. In this study, we compared the smear layer productionat the apical third of the root canal wall between files with a triangular or rectangular cross-section shape.Methods: Thirty-two human premolar samples taken from mandibles were divided into two groups whose root canals were prepared using fileswith either a triangular (One Curve®, n=16) or rectangular (Hyflex EDM®, n=16) cross-section shape. After preparation, the root canals were irrigatedwith a combination of 2.5% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA). The smear layers in the apical third of the root canal walls wereobserved using a scanning electron microscope and quantified according to the Foschi scoring system.Results: The Mann–Whitney U-test revealed a significant difference between root canal preparations using the different file shapes. The groupprepared with the triangular file produced lower smear layer scores compared with the group prepared with the rectangular file.Conclusion: Root canal preparations using files with different cross-section shapes (e.g., triangular and rectangular), followed by irrigation with 2.5%NaOCl and 17% EDTA, produced smear layers in the apical third area. However, root canal preparations using files with a triangular cross-sectionshape were shown to reduce smear layer production compared with files with a rectangular cross-section shape

Highlights

Root canal treatment is a procedure to eliminate pulp infection and support periapical tissue healing, comprising three important steps, namely, access, cleaning and shaping, and obturation
The Kappa test value obtained before the definitive smear layer score determination was >0.8 (κ=0.904), indicating that the observers agreed in terms of the scoring system
While differences were observed, root canal preparation procedure still left a smear layer in the apical third of the root canal wall, regardless of instruments used for preparation in both groups

Summary

Introduction

Root canal treatment is a procedure to eliminate pulp infection and support periapical tissue healing, comprising three important steps (i.e., the endodontic triad), namely, access, cleaning and shaping, and obturation. During cleaning and shaping step, a thin smear layer may be produced when endodontic instruments touch the root canal wall, which consists of organic materials (collagen, odontoblast processes, pulp tissue, blood, and bacteria) and inorganic materials from unextracted dental debris (calcium hydroxyapatite and tricalcium phosphate) [2]. The presence of smear layer may clog dental tubules, providing substrates for bacterial growth and preventing antibacterial agents from entering the tubules. It may interfere with the obturation step and the overall success of endodontic treatment [3,4]. Smear layer may develop in apical third part of root canal, which is difficult to reach, making it a critical zone in the root canal treatment process [5]

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