 Abstract | | |
Context: The effect of chemical disinfection on gutta-percha (GP) has to be closely studied whether it affects surface topography and thereby causes leakage and reinfection of canals.
Aims: The purpose of the study is to assess the surface topography of GP cones after disinfecting with a novel disinfecting material, graphene oxide (GO), and compare the same with other disinfecting materials, including sodium hypochlorite (NaOCl) and silver nanoparticles (AgNps).
Settings and Design: After determining the power (0.84) of the study, 48 GP cones were taken and categorized into four different groups based on disinfecting agents.
Materials and Methods: Forty-eight GP cones (ISO size 30 6% taper, DIADENT) were taken and are randomly selected and grouped as follows according to the disinfecting agents: Group 1 – control (untreated GP points, n = 12), Group 2 – NaOCl (n = 12), Group 3 – AgNPs (n = 12), and Group 4 – GO (n = 12), respectively. After treating with the above disinfecting materials, the surface topography of samples was evaluated using atomic force microscopy. The data were analyzed statistically using one-way ANOVA and post hoc (Tukey's honestly significant difference) tests.
Statistical Analysis Used: IBM SPSS (version 21.0) software was used. The tests performed were one-way ANOVA and post hoc. Statistically, significance was set at a P ≤ 0.05.
Results: The root means square values and surface roughness values were lesser for the GO group and AgNPs when compared with the NaOCl group, which were statistically significant.
Conclusions: Within the limitations of the study, this study had shown lesser surface topography deterioration of GP cones when treated with GO and AgNPs, whereas more deterioration was observed with NaOCl.
Keywords: Atomic force microscopy; chemical disinfection; graphene oxide; silver nanoparticles; surface topography
How to cite this article:
Reddy K H, Chandran L, Mohan T M, Sudha K, Malini D L, Dominic B. Evaluation of the efficacy of a novel disinfecting material on the surface topography of gutta-percha: An in vitro study. J Conserv Dent 2023;26:94-7 |
How to cite this URL:
Reddy K H, Chandran L, Mohan T M, Sudha K, Malini D L, Dominic B. Evaluation of the efficacy of a novel disinfecting material on the surface topography of gutta-percha: An in vitro study. J Conserv Dent [serial online] 2023 [cited 2023 Feb 6];26:94-7. Available from: https://www.jcd.org.in/text.asp?2023/26/1/94/362919 |
| Introduction | |  |
Thorough disinfection and aseptic techniques are one of the main factors determining the success of root canal therapy; as per the contemporary concepts of infection control, every instrument and material needs to be sterilized when placed in the root canal. [1] At present, gutta-percha (GP) cones are the most commonly used material for the obturation of the root canal system. They are biocompatible, radiopaque, and thermoplastic in nature. Even though GP cones are produced under aseptic conditions and have some antimicrobial properties mainly due to their zinc oxide component, they can be contaminated by handling, aerosols, and physical sources during the storage and treatment process. Endodontic postgraduate students possess adequate knowledge of disinfecting GP cones, but regular practice is uncommon. The microbial assay showed that even freshly opened GP cones might be contaminated. Contamination of sterile root canal space with a potentially contaminated filling material can result in reinfection and treatment failure. Hence, disinfection of the obturating material is mandatory.[2],[3]
The dentist can treat cones either with decontaminating agent or ethylene oxide gas before using them for obturation. The latter process was found to be time-consuming and clinically impractical. Chemical disinfectants used for GP disinfection include sodium hypochlorite (NaOCl), glutaraldehyde, alcohol, iodine compounds, hydrogen peroxide, etc. Studies have shown that as a potent oxidizing agent, 5.25% NaOCl causes extreme topographic alterations in the cones, indicating aggressive deterioration.[4],[5] Moreover, crystal formation on the surface of GP cones has been identified after rapid sterilization with 2.5% and 5.25% NaOCl.[6] Therefore, an appropriate disinfectant is one that can be routinely used in dental clinics and can provide fast disinfection without modifying the structure of GP cones.
Aim of the study
This study aims to evaluate the surface topography of GP after disinfecting with a novel disinfecting material, graphene oxide (GO), and compare the same with other disinfecting materials, including NaOCl and silver nanoparticles (AgNps).
| Materials and Methods | | |
Forty-eight GP cones (ISO size 30 6% taper, DIADENT) were taken in this in vitro study. GP cones were randomly selected from the same batch (ISO size 30 6%).
Samples were sectioned 3 mm from their tip. Samples were divided into one control and three treatment groups as follows:
- Group I – untreated GP points (control group) (n = 12)
- Group II – GP points immersed in 5.25% NaOCl for 1 min (n = 12).(Prime dental Pvt. Ltd., Thane, Maharashtra, India)
- Group III – GP points immersed in 70 μg/ml AgNPs for 1 min (n = 12) (Nano Wings Pvt. Ltd., Khammam, Telangana, India)
- Group IV – GP points immersed in 80 μg/ml GO for 1 min (n = 12) (Nano Wings Pvt. Ltd., Khammam, Telangana, India).
Fresh liquid (5 ml) each of 5.25% NaOCl, AgNPs, and GO was used for each immersion period.
After the immersion, the samples were thoroughly rinsed with 5 ml of deionized water, and the specimens were dried with filter paper.
Atomic force microscopic analysis
All the samples were stuck to a glass slide with fast-setting cyanoacrylate glue. Each glass slide was viewed under an AFM (JPK NanoWizard®ULTRA Speed 2) using contact mode imaging. Then, the data were analyzed statistically using one-way ANOVA and post hoc tests [Figure 1], [Figure 2], [Figure 3], [Figure 4].
Statistical analysis
IBM SPSS (Version 21.0. Armonk, NY: IBM Corp.) software was used to carry out the statistical analysis of data. Root mean square (RMS) and surface roughness parameters were used to compare the structure of GP points with contact mode imaging. These values were analyzed using one-way ANOVA and post hoc (Tukey's honestly significant difference) tests. They were considered statistically significant when P < 0.05.
| Results | | |
The RMS values and surface roughness values were lesser for the GO group and AgNPs when compared with the NaOCl group, which were statistically significant [Table 1].
| Discussion | | |
Dentists occasionally face the problem of infections that occur after the obturation of root canal space. It may be due to the introduction of contaminated GP cones into the root canal.
Studies have proved that 5.5% of GP cones taken from boxes are contaminated.[7],[8] Due to their thermoplastic nature, conventional sterilization methods cannot be used. Therefore, chairside disinfection using different chemical disinfectants before obturation is recommended. Various chemical agents have been proposed as GP disinfectants, including NaOCl, chlorhexidine, glutaraldehyde, alcohol, iodine compounds, hydrogen peroxide, MTAD, etc.
The most common and reliable technique for disinfection of GP cones is placing them into 5.25% NaOCl for at least 1 min.[9] In endodontic practice, NaOCl is one of the most common disinfectants used in concentrations that range from 0.5% to 5.25%.[5] However, NaOCl can cause surface alterations of the GP cones due to salt precipitations, negatively impacting the sealing ability when used with resin-based sealers.[10],[11] Hence, in the present study, a novel disinfecting material, GO, is used, and the surface alteration of GP is studied.
Graphene is one of the most promising nanomaterials, and it has a two-dimensional carbonaceous material and serves as an essential structural element of graphite. Since the synthesis of graphene, many derivatives have been studied, such as GO and reduced GO. Mainly, GO, a precursor of large-scale graphene synthesis, has attracted attention for its multitargeting killing strategy, simple production, and low cost. GO has oxygen-containing functional groups, such as epoxy and hydroxyl groups on its basal planes and carboxylic acid groups at its edges. Exhibit excellent antimicrobial properties and have been adopted as antimicrobial nanomaterials due to their ability to disrupt bacterial cell membranes' integrity and produce reactive oxygen species. Three main antimicrobial activities have been reported as follows:
- GO sheet's sharp edges can physically interfere with a microorganism by cutting bacteria membranes
- GO can induce oxidative stress
- Can wrap and isolate microorganisms from the environment to not find nutrition, stopping proliferation.[12]
There are numerous potential applications of GO in biomedicine, such as biological and molecular imaging, drug/gene delivery, cancer therapy, tissue scaffold, and as an antibacterial agent. It also seems to be an exciting material for dental use, particularly in the endodontic/restorative fields. The minimum bactericidal concentration was 40 μg/mL for planktonic Streptococcus mutans. When the concentration was 80 μg/mL, 80% of the bacteria in the biofilms were devitalized. GO film demonstrated a role in inhibiting bacterial film proliferation, and it showed acceptable adhesion properties to root dentin without causing alteration of its structure.[13]
AgNPs are among the most well-studied nanomaterials due to their wide range of antimicrobial properties against various bacteria, viruses, and fungi. AgNPs are nontoxic to the human body at low concentrations and have a broad spectrum of antibacterial actions. However, especially at higher concentrations, it can be toxic to human cells and possibly affect human health.[14]
In the present study, atomic force microscopy is used since it provides three-dimensional imaging of molecular surfaces of nanometer resolution. It does not require any special treatment (metal coating) compared to a scanning electron microscope and can be operated effectively even in the air or liquid medium.
In this study, NaOCl-treated GP had shown the highest surface alterations, which are per studies done by Valois et al.[6] and Tilakchand et al.[5] Both GO and AgNPs had shown fewer surface alterations when compared to NaOCl. Hence, these nanoparticles can be used as an alternative for disinfecting GP cones.
Limitations of the study
Although the above nanoparticles show lesser surface alteration, further research in this area should be conducted to investigate these nanoparticles' surface energy and wetting ability to analyze their compatibility with sealers when used as irrigating solutions.
| Conclusions | | |
Within the limitations of the present in vitro study, it can be concluded that GO and AgNPs had shown lesser surface deterioration when compared to NaOCl. Hence, these nanoparticles can be used as an alternative for disinfecting GP cones. GO is a promising material, and its potential use in endodontics should be investigated.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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Correspondence Address:
Dr. Lekshmi Chandran
Department of Conservative Dentistry and Endodontics, Government Dental College and Hospital, Vijayawada, Andhra Pradesh - 520 004
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jcd.jcd_417_22
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1] |
