RGUHS Nat. J. Pub. Heal. Sci Vol No: 17 Issue No: 1 pISSN:
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1Dr. Medha Kulkarni, Lecturer, Department of Conservative Dentistry and Endodontics, KLE Vishwanath Katti Institute of Dental Sciences, Maratha Mandal Dental College and Research Center, Belagavi, Karnataka, India.
2Department of Conservative Dentistry and Endodontics, Maratha Mandal Dental College and Research Center, Belagavi, Karnataka, India
3Department of Conservative Dentistry and Endodontics, Maratha Mandal Dental College and Research Center, Belagavi, Karnataka, India
4Department of Conservative Dentistry and Endodontics, KLE Vishwanath Katti Institute of Dental Sciences, Maratha Mandal Dental College and Research Center, Belagavi, Karnataka, India
5Department of Conservative Dentistry and Endodontics, Government Dental College, Pudukkottai, Tamil Nadu, India
*Corresponding Author:
Dr. Medha Kulkarni, Lecturer, Department of Conservative Dentistry and Endodontics, KLE Vishwanath Katti Institute of Dental Sciences, Maratha Mandal Dental College and Research Center, Belagavi, Karnataka, India., Email: medhakulkarni897@gmail.com
Abstract
Aim: To evaluate and compare the push-out bond strength (PBS) of AH Plus sealer to radicular dentin treated with ethylenediaminetetraacetic acid (EDTA), neem leaf extract (NLE), and apple cider vinegar (ACV) as final root canal irrigants.
Methods: Thirty-six extracted human permanent single-rooted teeth were decoronated and instrumented using the Protaper Universal rotary system up to size F3. The samples were randomly assigned into three groups (n = 12) based on the final irrigant used: Group I - 17% EDTA, Group II - NLE, and Group III - ACV, followed by a final rinse with saline. Canals were dried and obturated using AH Plus sealer and F3 gutta-percha cones. After 24 hours, each root was sectioned into 3-mm thick slices (coronal, middle, and apical thirds). PBS was assessed using a universal testing machine at 1 mm/min crosshead speed. Data were analyzed using one-way ANOVA and Tukey’s post-hoc test.
Results: EDTA exhibited the highest PBS in the middle and apical thirds compared to NLE and ACV, while NLE demonstrated significantly greater bond strength in the coronal third.
Conclusion: EDTA showed superior PBS overall, making it the most effective final irrigant among those tested. However, neem leaf extract demonstrated promising results in the coronal region and may serve as a viable herbal alternative. Further clinical studies are warranted to validate and standardize the use of herbal irrigants in endodontics.
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Introduction
A successful endodontic procedure requires thorough cleaning and shaping of the root canals, as well as a biocompatible and dimensionally stable filling material, for a three-dimensional filling that provides a fluid-tight seal.1 Sodium hypochlorite (NaOCl) is a popular 29 irrigating solution due to its strong antibacterial and tissue disintegration properties; however, it cannot remove the smear layer.2 Chelating compounds work well to remove the inorganic part of the smear layer. The most widely utilized chelating agent that successfully eliminates the smear layer is ethylenediaminetetraacetic acid (EDTA), with substantial support in the existing literature.
EDTA is a white, water-soluble polyamine carboxylic acid.3 It can sequester metal ions like Ca2+ and Fe3+, and functions as a chelating agent and a hexadentate ligand. Metal ions bound by EDTA stay in the solution, but become less reactive. Two of the salts that are made from EDTA are disodium EDTA and calcium disodium EDTA.3 Ferdinand Munz created the chemical using ethylene diamine and chloroacetic acid, and he published its first description in 1935. Currently, sodium cyanide, formaldehyde, and ethylene diamine are the primary ingredients used in the synthesis of EDTA, which combines with the calcium ions present in dentine to form soluble calcium chelates. According to the reports, dentin could be decalcified in five minutes to a depth of 20-30 micrometers using EDTA.4 Nevertheless, it does have certain adverse consequences such as, dentinal erosion which may result from using 17% EDTA in root canals for longer than a minute. Moreover, radicular dentin may experience demineralization effects from EDTA, which would lower dentin microhardness.5
Consequently, much research has been conducted focusing on the herbal irrigants due to their high antibacterial activity, biocompatibility, and easy accessibility. Among the various herbal irrigants studied, Apple cider vinegar (ACV) has been used as an irrigant during chemo-mechanical process because of its promising results, which are comparable to those of EDTA.6 In a few in vitro experiments, Neem leaf extract was found to be more successful in eliminating smear layer when compared to different other herbal agents used as irrigants.7
In several investigations, Apple cider vinegar was found to be an effective chelating agent with bactericidal effects against microorganisms responsible for infections of endodontic and periapical tissues.8 The bond strength between the dentin, obturating agents, and sealers determine the results of endodontic therapy. As a result, techniques for push-out testing have been created to evaluate this characteristic of restorative materials.9 Since irrigants can affect the bond-strength of resin sealers, this study was conducted to evaluate the effects of EDTA and herbal extracts (Apple cider vinegar and Neem) as final irrigating solutions on the push-out bond strength of AH Plus sealer.
Materials and Methods
Formulation of Neem leaf extract
Fifty grams of Neem leaf powder and 500 millilitres of purified water were mixed and heated to 100° Celsius to create 50 millilitres of Neem leaf extract (Figure 1).
Preparation of specimen
The present study employed thirty-six mandibular premolar teeth that were single-rooted and had completely formed apices. To achieve a uniform working length of 15 millimetres, the samples were de-coronated at the CEJ using a slow-speed handpiece and diamond disc with water cooling. A size 10 K-file was inserted into the canal and beyond the apex. 1 mm millimetre was subtracted from this measurement to determine the working length. All of the experimental irrigating solutions were irrigated using a syringe and a 30-gauge needle. Dentsply Maillefer's ProTaper Universal rotary devices were employed to prepare the root canals up to size F3. During the shaping procedure, in between instrument changes, the specimens were irrigated with 2.5 mL of 5.25% sodium hypochlorite (NaOCl). After that, an intermediate saline irrigation was performed, and finally the experimental irrigant 17% EDTA for Group 1 specimens, Neem leaf extract for Group 2 specimens, and Apple cider vinegar extract for Group 3 specimens-were used for a minute. To dry the specimens, paper points were used. The root canals were smeared with AH Plus sealer, filled with a single gutta-percha cone (F3, Dentsply Sirona), and laterally compacted. Following a 24-hour obturation period, each specimen was sectioned to maintain a uniform thick-ness of 3 mm, perpendicular to its long axis, using a precision saw operated at a low speed under water cooling (Figure 2).
Pushout examination
A cylindrical stainless-steel plunger with a diameter of 2 mm was used to load the specimen on a Universal testing machine, at a pace of 1 mm/minute until debonding took place. For each sample, the load needed to displace the root fills was noted (Figure 3).
Statistical analysis
The descriptive data for pushout bond strength were presented as mean ± standard deviation (SD) for every group. ANOVA was utilized to evaluate the pushout bond strength among three groups (Groups 1, 2, and 3), as well as across coronal, middle, and apical regions. For pairwise comparisons, Tukey’s post hoc test was applied. To illustrate the data graphically, simple bar charts were used. A value of P <0.05 was considered statistically significant. The analysis was done using SPSS version 19 software.
Results
Compared to the two groups in which herbal irrigants were used (ACV and Neem), the group that received EDTA irrigation had the strongest push-out bond strength (PBS) in the middle and apical thirds. However, in the coronal third, the group that received Neem leaf extract as the final irrigation had a significantly higher PBS value than the other two groups, with a statistically significant difference.
Discussion
To achieve a three-dimensional filling, the root canal system must be thoroughly cleaned, shaped, and free of pathogenic organisms. Root-filling material that is both dimensionally stable and biocompatible must be used to fill the root canals in all the three dimensions. Gutta-percha cannot adhere to the radicular dentin all by itself.2 Hence to achieve adhesion, sealers are used. An enormous variety of sealers are available in the market, ranging from epoxy resin-based sealers to the ZOE-based sealers that were first introduced.9 Due to their improved sealing, reduced solubility, satisfactory biological performance, and attractive physical characteristics, epoxy resin-based sealers like AH Plus are gradually replacing other modern sealers with enhanced micro-retention to the root dentin.
To clean the root canals satisfactorily, to lubricate the dentinal walls, to clear away the debris, and to dissolve both inorganic and organic debris, chemical irrigants are essential. These agents also enhance the bonding capacity of resin-based sealers to radicular dentin due to their previously stated functions. Instrumentation and simultaneous use of irrigants facilitate breaking down of the biofilm and improves disinfection. For many years, many chemical agents have been used, such as hydrogen peroxide, urea peroxide, saline, and sodium hypochlorite. The most popular irrigant is sodium hypochlorite because of its potent antibacterial properties, and its ability to dissolve necrotic tissues and organic constituents. The side effects of NaOCl include bad odour and taste, toxicity, the possibility of mandibular nerve paraesthesia, allergic reactions, dentin degeneration due to collagen breakdown, and increased microleakage of coronal adhesive restorations. It has been shown that NaOCl when used as a final flush can inhibit AH Plus sealers from polymerizing.9 Therefore, the choice of final irrigant in root canal therapy can influence the properties of the sealer and obturating substances, as well as their adhesion to radicular dentin.
Following shaping, canal surfaces and tubules of radicular dentin are frequently covered with an irregular, amorphous smear layer. Organic and inorganic components, including pulp tissue, bacteria, and dentin debris, make up the smear layer. There is a need for this smear layer to be removed as it can house and harbour several pathogenic microbes and necrotic tissues. It acts as a barrier to stop sealers and irrigants from penetrating dentinal tubules, which leads to compromised disinfection and eventually leads to microleakage and failure of root canal treatment.10-11 The most common and advised strategy is to use 17% EDTA to remove the smear layer and sodium hypochlorite for disinfecting the root canals. Despite their great efficiency, these irrigants are associated with certain disadvantages.
Since most traditional irrigants are cytotoxic, there has been an increasing interest in employing herbal irrigants with medicinal qualities in recent years. Diverse research has produced conflicting results on the antibacterial activity and the ability of herbal irrigants to remove smear layer. Numerous in vitro studies have evaluated several herbs, such as curcumin, triphala, neem, aloe vera, etc., as irrigants and have established their antibacterial properties. So far, not much research has been conducted to evaluate these compounds' ability to eradicate the smear layer. According to the tests conducted recently, Neem leaf extract and apple cider vinegar demonstrated antibacterial activity and the ability to remove smear layer in a manner comparable to EDTA (17%).
Azadirachta indica, commonly referred as ‘Indian neem’ or the ‘Margosa tree’, is a widely used traditional medicinal herb in India. In several regions of the nation, it is also revered as a sacred plant. Every portion of the tree has some therapeutic qualities, and research has shown that the leaf extract possesses antibacterial properties. Biologically active substances found in neem leaves include flavonoids, isoprenoids, alkaloids, glycosides, tannins, and acid metabolites such as nimbidic acid, gallic acid, and ferulic acid.12 These active ingredients are responsible for the capacity to remove the smear layer and for the antibacterial effect.13 On comparing Neem leaf extracts to other herbal irrigants such as triphala, amla, and tulsi, it has been found that extract of neem leaf was the most effective in eliminating the smear layer.14
According to earlier research, root canal sealers have a weak capacity to bond to the apical dentine. The current study also found that bond strength declined from the coronal third to the apical third. Inadequate volume or penetration of the irrigants into the apical portion could be the probable reason and this can be attributed to the structure and significantly smaller number of tubules in the apical third.15-16 The presence of cementum-like tissue apically on the root canal wall can result in decreased adhesive penetration compared to the coronal third.17
There was no apparent difference between Group 1, Group 2, and Group 3 in the middle and apical thirds. However, a statistically significant difference was seen in the coronal third which exhibited higher values of PBS in the group irrigated with neem leaf extract compared to the other groups. This could be due to the presence of the previously stated acid metabolites in neem leaf extract, that decrease bacterial adherence to root canal walls and reduce bacterial colonization.18 This might lead to efficient eradication of the smear layer, but its superiority to EDTA for the same is questionable and demands further research.
The shortcomings of the current study include the possibility that in vivo result may vary based on a range of potential parameters, such as canal structure and ramifications, lateral canals, etc. Additionally, the masticatory load can also vary from person to person. After obturation, the specimens should have been subjected to thermocycling to simulate intraoral masticatory load. The irrigation and activation protocols among clinicians are not standardized worldwide. Also, the pushout testing was done on thinner sections which may or may not be associated to the bulk of the tooth. To find if these results hold true for different activation techniques and different commercially available sealers, more research is needed in the future.
Conclusion
The results of this in vitro study indicate that, among all the irrigants tested, the pushout bond strength of AH Plus sealer to root canal dentin was significantly higher when 17% EDTA was used as the final irrigant. Since Neem leaf extract exhibits optimal performance in coronal thirds and does not negatively impact the bond strength of AH Plus, it can serve as a good substitute for the final irrigants that are currently in use. The potential application of herbal remedies in routine endodontics is discussed in this study. Nonetheless, further clinical research is necessary to standardize the irrigation protocol using herbal medicines.
Supporting File
Figure 1: a) Neem leaf powder with water being heated at 100 degrees Celsius, b) Whatman filter paper, c) Neem leaf extract, d) Apple cider vinegar" width="200px" src="https://hm-journals.s3.ap-south-1.amazonaws.com/home/journals/DCXXfCu6xskFttxHXTvuOCyARxW2oK18cT4EYB6I.png">
Figure 2: a) 36 single-rooted teeth, b) Decoronated samples, c) Establishing working length, d) Canal prepared till F3 Protaper Universal, e) Obturation with F3 Gutta percha and AH plus sealer, f) Decoronated sections of 3 mm measured using vernier calliper g) Decoronated sections mounted in cold cure acrylic resin, h) Final Specimen" width="200px" src="https://hm-journals.s3.ap-south-1.amazonaws.com/home/journals/yHwveBfaeqE1ZE0wsfZZno7P0DcnAECnvck10T13.png">
Figure 3: Specimen subjected to Universal Testing Machine References
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