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Year : 2019  |  Volume : 9  |  Issue : 2  |  Page : 109-112

Effect of chelating agents on the microhardness of Biodentine

Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India

Date of Web Publication3-Apr-2019

Correspondence Address:
Dr. Nidambur Vasudev Ballal
Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Manipal Academy of Higher Education, Manipal - 576 104, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sej.sej_79_18

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Introduction: The objective of this study was to evaluate the effect of SmearOFF, 7% maleic acid (MA) and 17% ethylenediaminetetraacetic acid (EDTA), on the surface microhardness of Biodentine (BD).
Materials and Methods: Forty BD cylindrical-shaped specimens were prepared using a split mold and were divided randomly into four groups (n = 10) based on the type of irrigant used for 1 min. In Group I, the specimens were treated with 17% EDTA, in Group II with 7% MA, in Group III with SmearOFF solution, and in Group IV with 5 mL distilled water. In all these groups, the irrigants were taken in a beaker and the samples were immersed with a magnetic stirrer placed to ensure complete wetting of the specimens. All the samples were then washed with distilled water and air-dried. The surface microhardness of the specimens was measured using Knoop hardness tester. Data were analyzed statistically using Kruskal–Wallis and Mann–Whitney U-test. The significant level was preset to P = 0.05.
Results: MA significantly compromised the microhardness of BD followed by EDTA, SmearOFF, and distilled water which was statistically significant (P < 0.001). On comparison between 17% EDTA and SmearOFF, 17% EDTA reduced microhardness to maximum (P < 0.05).
Conclusion: In conclusion, the present study demonstrated that microhardness of BD cement was generally affected by chelating agents.

Keywords: Biodentine, ethylenediaminetetraacetic acid, irrigation, maleic acid, microhardness, SmearOFF

How to cite this article:
Ballal NV, Mishra P, Rao S, Upadhyay ST. Effect of chelating agents on the microhardness of Biodentine. Saudi Endod J 2019;9:109-12

How to cite this URL:
Ballal NV, Mishra P, Rao S, Upadhyay ST. Effect of chelating agents on the microhardness of Biodentine. Saudi Endod J [serial online] 2019 [cited 2022 Sep 30];9:109-12. Available from: https://www.saudiendodj.com/text.asp?2019/9/2/109/255371

  Introduction Top

A diversity of calcium silicate-based materials has been advanced recently in endodontics for various applications such as perforation repair, vital pulp therapy, apical plugs, root end filling, and root canal obturation.[1],[2],[3] Mineral trioxide aggregate (MTA) is one of the commonly used calcium silicate-based cement in endodontics. Several studies have demonstrated the potential of MTA to be used in clinical cases.[4],[5] Despite its numerous favorable properties, it has several shortcomings such s long setting time, high solubility, discoloration potential, handling difficulties, and expensive.[4],[6],[7] Biodentine (BD) (Septodont, St. Maur-des-Fosses, France) is a calcium silicate-based material which has shown to overcome the shortcomings of MTA. It consists of tricalcium silicate, zirconium oxide, calcium carbonate and a water-based liquid. This liquid contains calcium chloride accelerator and water as a reducing agent.[8],[9] BD has good sealing ability, short setting time, high compressive strength, low discoloration potential, biocompatibility, and biomineralization properties.[8],[10],[11],[12],[13] Due to its favorable properties, it is suggested to be used as an endodontic repair material such as perforation to minimize the bacterial contamination and irritation to periodontium due to the seepage of irrigating solutions.[14]

The fundamental requirements for the success of the root canal treatment are shaping and cleaning of the root canal system. This can be accomplished using a combination of mechanical instrumentation and chemical irrigating solutions. The instrumentation of the root canals with either manual or rotary methods produces amorphous smear layer which contains inorganic dentin debris along with organic materials such as pulp tissue, necrotic debris, microbes, and their metabolic products.[15],[16] Removal of smear layer during endodontic treatment will result in achieving a three-dimensional fluid-tight seal of the root canal system[17] as well as facilitating the penetration of intracanal medicaments and root canal sealers into the infected dentinal tubules.[18],[19] Combined application of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) is generally used for the efficient removal of the smear layer from the root canal system.[20]

Maleic acid (MA) is a smear layer removal agent which has displayed significant smear layer removal capacity compared to 17% EDTA, particularly in the apical third of the root canal system.[21],[22] It has also revealed less cytotoxicity when compared to that of EDTA.[23] SmearOFF (Vista Dental Inc., USA) is a smear layer removal agent recently introduced into endodontics. It consists of EDTA and chlorhexidine gluconate (CHX). The manufacturer claims that it does not form a precipitate when mixed with NaOCl and thus does not require an additional rinse following NaOCl irrigation.[24] In addition, the manufacturer claims that SmearOFF yields better calcium suspension and clears more dentinal tubules compared to EDTA. In general, it should not be used concurrently with NaOCl because of the rapid displacement of available chlorine.[25]

The endodontic repair material often comes in contact with various endodontic irrigants during shaping and cleaning of the root canal system. Guneser et al.[26] have evaluated the influence of different root canal irrigating solutions on the push out bond strength of BD and MTA. They concluded that BD demonstrated a considerable performance after being exposed to root canal irrigants as compared to MTA. Ballal et al.[27] evaluated the effect of various acids on the microhardness, surface topography, and push out bond strength of BD to root canal dentin. They reported that MA, EDTA, and phosphoric acid altered the surface morphology and reduced the microhardness of BD. Till date, there are no studies evaluating the effect of SmearOFF on the microhardness of BD. Hence, the aim of this in vitro study was to evaluate the effect of SmearOFF, 7% MA, and 17% EDTA on the surface microhardness of BD.

  Materials and Methods Top

A prefabricated split mold of 6 mm height and 4 mm diameter [Figure 1] was used to prepare forty BD cylindrical-shaped specimens by mixing the BD material according to the manufacturer's instructions. The BD liquid from a single-dose container was emptied into a powder containing capsule, mixed for 30 s at 4000 rpm, carried into the mold using MTA carrier (Dentsply, Tulsa Dental, USA), and packed using a condenser. All the specimens were wrapped in wet gauze and stored at room temperature for 1 week. Then, the specimens were grounded smooth and flat with silicon carbide abrasive papers (1000 and 1200 grit) under distilled water for removing any surface scratches and then polished with 0.1 μm alumina suspension (Ultra-Sol R, Eminess Technologies Inc. Monroe, NC) on a rotary felt disk. Specimens were then randomly divided into four groups (n = 10) based on the irrigant used:
Figure 1: Customized brass mold

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  • Group 1: The specimens were treated with 17% EDTA (Merck, Darmstadt, Germany) for 1 min
  • Group 2: The specimens were treated with 7% MA (KMC Pharmacy, India) for 1 min
  • Group 3: The specimens were treated with SmearOFF solution for 1 min
  • Group 4: The specimens were treated with 5 mL distilled water (control) for 1 min.

In all these groups, the irrigants were taken in a beaker and the samples were immersed with a magnetic stirrer placed to ensure complete wetting of the specimens. After 1 min of treatment, all the specimens were washed with distilled water and air-dried. The surface microhardness of the specimens was measured using Knoop hardness tester (Matsuzawa Seiki Co. Ltd, Tokyo, Japan), with the indentations made using diamond indenter at three different locations using 200 g load and 20 s dwell time. The diamond-shaped indentations were observed in an optical microscope with a digital camera, and the length of the two diagonals was measured accurately using image analysis software (Matsuzawa Seiki Co. Ltd, Tokyo, Japan) for calculating the microhardness value. The representative hardness value for each specimen was acquired as the average of the results of the three indentations.

Statistical analysis

The microhardness values among the different experimental groups were analyzed statistically using Kruskal–Wallis and Mann–Whitney U-test. For all analyses, the significance level was preset at P = 0.05.

  Results Top

The mean microhardness values between the different experimental groups are shown in [Figure 2]. The MA group reduced the microhardness to the maximum and distilled water reduced to minimum as compared to SmearOFF and 17% EDTA which was statistically significant (P < 0.001). On comparison between 17% EDTA and SmearOFF, 17% EDTA reduced microhardness to maximum (P < 0.05).
Figure 2: The mean Knoop hardness values of different experimental groups. Different uppercase letters indicate significant differences between four groups after application of test solutions

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  Discussion Top

BD was reported to display a remarkably consistent performance even after exposure to an endodontic irrigant such as NaOCl, CHX, and saline solutions regardless the effect on the surface morphology of BD.[26] Similar findings were reported by Ballal et al.[27] The present study assessed the effect of SmearOFF irrigating solution on the microhardness of BD cement. All the chelating agents used influenced the microhardness of BD when compared to the distilled water. The microhardness of BD was reduced significantly when it was treated with 7% MA. This may be due to the acidic pH of 7% MA (1.3) which must have inhibited the complete setting of BD. It has been demonstrated by the previous studies that the physical properties of calcium silicate cement are affected by low pH environment.[28],[29] In addition, the mechanical properties (compressive strength) of different tricalcium silicate cement get deteriorated in the presence of an acidic environment.[30] The low pH might inhibit the setting reaction, adhesion, and increase the solubility of calcium silicate cement which can affect the surface microhardness.[28],[31] Furthermore, it has been reported that acidic pH causes modifications on the BD surface morphology which in turn may affect the surface hardness.[32]

In the present study, the specimens treated with 17% EDTA showed significantly lower hardness when compared to SmearOFF and distilled water. This may be attributed to chelation of the calcium ions released from BD by EDTA during hydration which lowers its hardness value due to poor crystallization.[33],[34]

In the present study, the superior effect of SmearOFF on the microhardness of BD cement may be attributed to its alkaline pH of 7.2. The combination of CHX and EDTA present in SmearOFF solution would have chelated lesser calcium ions released from BD cement resulting in improved microhardness of BD. Furthermore, Krishnan et al. reported that SmearOFF when mixed with NaOCl solutions causes a marked reduction in free available chlorine in a similar manner to that of EDTA.[25] They concluded that its combined use with NaOCl could not be recommended. Hence, use of EDTA or MA should be minimized in root canals restored with BD in order to prevent the deterioration of BD material, which is important for its long-term success in endodontic procedures.

Microhardness of a material is influenced by its yield strength, tensile strength, modulus of elasticity, and stability of its crystal.[35],[36] It is an indicator of the overall strength or resistance to deformation of a material.[37] Evaluation of microhardness is clinically important, especially when BD cement is placed in areas of furcal perforation repairs.

  Conclusion Top

In conclusion, the present study demonstrated that microhardness of BD cement was affected by chelating agents. SmearOFF can be used as a safe endodontic irrigant in canals restored with BD.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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