Journal of Interdisciplinary Dentistry

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 11  |  Issue : 1  |  Page : 21--26

Sealing ability of zinc oxide–eugenol and zinc oxide–Aloe vera combination as a root canal sealer: An in vitro comparative scanning electron microscopy analysis


N Mehreen Kulsum, Bikash Jyoti Borthakur, B Swathika, S Ganesan 
 Department of Conservative Dentistry and Endodontics, Mahatma Gandhi Postgraduate Institute of Dental Sciences, Puducherry, India

Correspondence Address:
Dr. N Mehreen Kulsum
Department of Conservative Dentistry and Endodontics, Mahatma Gandhi Postgraduate Institute of Dental Sciences, Puducherry - 605 006
India

Abstract

Background: Zinc oxide–eugenol is the most commonly used sealer. However, it has irritating and cytotoxic effects. Therefore, research in this field was being carried out to develop newer root canal sealers. Aloe vera gel is known for its medicinal properties. Thus, an attempt has been made to replace eugenol with Aloe vera. Aims: To compare the sealing ability of zinc oxide–eugenol and zinc oxide–Aloe vera, as a root canal sealer by in vitro scanning electron microscopy (SEM) analysis. Materials and Methods: Thirty freshly extracted single-rooted anterior teeth were selected and randomly divided into two equal groups. Access cavities were prepared, and canals were irrigated and instrumented followed by obturated with a zinc oxide–eugenol sealer and gutta-percha for Group I, whereas for Group II, zinc oxide–Aloe vera sealer was used with gutta-percha. The teeth were longitudinally split into two halves and subjected to SEM analysis to assess interface between obturating material and dentin. Statistical Analysis: Data obtained were analyzed by Student's t-test. Results and Conclusions: Zinc oxide–Aloe vera showed significantly better sealability as compared to zinc oxide–eugenol sealer (P ≤ 0.05). The analyzed data revealed that zinc oxide–Aloe vera as a root canal sealer is a better alternative to zinc oxide–eugenol.



How to cite this article:
Kulsum N M, Borthakur BJ, Swathika B, Ganesan S. Sealing ability of zinc oxide–eugenol and zinc oxide–Aloe vera combination as a root canal sealer: An in vitro comparative scanning electron microscopy analysis.J Interdiscip Dentistry 2021;11:21-26


How to cite this URL:
Kulsum N M, Borthakur BJ, Swathika B, Ganesan S. Sealing ability of zinc oxide–eugenol and zinc oxide–Aloe vera combination as a root canal sealer: An in vitro comparative scanning electron microscopy analysis. J Interdiscip Dentistry [serial online] 2021 [cited 2021 Jun 21 ];11:21-26
Available from: https://www.jidonline.com/text.asp?2021/11/1/21/314184


Full Text



 Clinical Relevance to Interdisciplinary Dentistry



The present study aimed to improve sealing ability of root canal sealer and thus to prevent the microleakage between the restoration and tooth interfaceTo overcome toxicity caused by eugenol by replacing it with Aloe vera gel which is nontoxicAloe vera gel is being widely used in dentistry to treat oral ulcer, denture stomatitis, irrigant in endodontics, and mouthwash.

 Introduction



Aloe vera has “Antrokinon” as phytochemical that are known to have antimicrobial effect. It has analgesic, anti-inflammatory, antioxidative, and wound healing properties with minimal cytotoxicity.[1] Although zinc oxide–eugenol is the most commonly used sealer, eugenol has irritating effects on oral tissues, its higher concentration is more cytotoxic, and does not adhere to root canal dentin.[2],[3] Being sticky in nature, it is expected that Aloe vera gel mixed with zinc oxide adheres better to the walls of root canal dentin. The present study aims to evaluate the sealability of zinc oxide–Aloe vera as a root canal sealer using scanning electron microscopy (SEM) analysis.

 Materials and Methods



Thirty freshly extracted single-rooted anterior teeth with fully formed apices were selected, thoroughly cleaned, and stored in distilled water, until they were used and randomly divided into two groups, with fifteen specimens in each group (n = 15)

Group I: Zinc oxide–eugenolGroup II: Zinc oxide–Aloe vera gel.

Extraction of Aloe vera gel

The fully extended leaves of Aloe vera (Aloe Vera Barbadensis) were selected and washed with distilled water. The parenchymatous covering of the leaves were then peeled off, and the fresh pulp was collected. This fresh pulp was then being mixed with zinc oxide powder on a glass slab in the mixing ratio of 2:1 by volume.[4] By mixing one part of zinc oxide powder with two drops of Aloe vera for 30-60sec to get a smooth creamy cohesive consistency. Consistency is tested by string-out test and drop test by raising the spatula from the glass slab; the smooth creamy mix should string out at least one inch before breaking and the suspended mix should cling to the inverted spatula blade for 10–15 s before dropping as shown in [Figure 1].{Figure 1}

Access cavities were prepared, canal patency was determined by passing a size 10 k-file through the apical foramen, working length was estimated 1 mm short of apical foramen, and canals were instrumented by step-back technique from #10 to #35 size K-files (Mani Inc., Tochigi Ken, Japan). Sodium hypochlorite (Prime Dental Products Pvt Ltd., Thane, Maharashtra, India) and saline (0.9% Sodium chloride, Aculife, India) were used as irrigants. Canals were dried with sterile #15 absorbent paper points (ISO 0.02 size, Dentsply, Maillefer, USA) and obturated with zinc oxide–eugenol sealer (DentPro, India) and gutta-percha material for Group I, whereas for Group II, zinc oxide–Aloe vera was used as a sealer with gutta-percha by lateral condensation method. After obturation, the specimens were stored for 48 h at room temperature and allowed for the complete set of the sealer.

After that, superficial longitudinal grooves were made along the mesial and distal wall of the roots using the diamond disc with a slow-speed handpiece. The teeth were split longitudinally into two halves using a chisel and mallet to reduce debris collection. Finally, the teeth subjected to SEM analysis [Central Leather Research Institute under Council of Scientific and Industrial Research, Adyar, Chennai, Tamil Nadu, India] to assess and measure the interface between the obturating material and the root canal dentin.

The mean and standard deviation were estimated from the obtained result that was statistically analyzed using the Student's t-test to find out the significant difference in sealing ability between the two groups studied. A significance of P ≤ 0.05 was considered. The statistical analysis was conducted by IBM SPSS statistics 20 software (SPSS for Windows: SPSS Inc., Chicago, IL, USA).

 Results



In the present study, the microleakage at the interface of zinc oxide–eugenol and zinc oxide–Aloe vera with the root canal dentin were measured using ImageJ software from SEM images at 500X,2000X,6000X magnification as shown in [Figure 2]. The mean values and standard deviation were estimated from the obtained results; Student's t-test was used to find the significant difference between the two groups studied using SPSS version 20 [Table 1]. There was a statistically significant difference noted between zinc oxide–eugenol and zinc oxide–Aloe vera in 500X,2000X,6000X with P ≤ 0.05 using t-test as shown in [Table 1].{Figure 2}{Table 1}

The mean microleakage value for zinc oxide–eugenol group was 48.12 at at 500X, 51.99 at 2000X, and 41.50 at 6000X, whereas for zinc oxide–Aloe vera group was 34.45 at 500X, 30.12 at 2000X, and 25.05 at 6000X magnification. The mean value of microleakage at various magnification for zinc oxide–Aloe vera was less as compared to conventional zinc oxide–eugenol sealer with statistically significant difference noted among them. Thus zinc oxide–Aloe vera has less microleakage with adequate sealability with root canal dentin. The mean distribution of zinc oxide–eugenol and zinc oxide–Aloe vera at 500X,2000X,6000X is shown in [Figure 3].{Figure 3}

 Discussion



Endodontic treatment aims to eliminate infection of the root canal system and to obturate the root canal space in three-dimensions, to prevent apical and coronal penetration of liquids and microorganisms. Achieving adequate seal prevents microorganisms from reaching apical and periapical tissues. Hence, the success of endodontic treatment depends on the coronal and apical sealing.

Most root canals are filled with gutta-percha points in combination with an endodontic sealer; these are the essential components of root canal obturation to establish an impervious seal. Gutta-percha is the most popularly used root canal filling material which has got acceptance for more than 150 years. However, gutta-percha alone does not possess the sealing ability to give water-tight seal at the periapex. Hence, a sealer must be used to attain the three-dimensional seal. It has been shown by various authors that teeth obturated with gutta-percha and sealer display a better seal than those obturated without sealer. Different types of sealers have been used in conjunction with gutta-percha for root canal obturation with varied success rates. However, till date, there is no sealer which fulfils all the specifications and criteria of an ideal root canal sealer.

The primary function of a sealer is to seal the spaces between the core material and the dentinal walls of the root canal and between the gutta-percha cones, in an attempt to form a coherent mass of obturating material without voids. Incomplete adaptation of the root canal obturating material to the canal wall may lead to the accumulation of both stagnant tissue fluid and microorganisms, which may cause periapical disease and, thus, may lead to failure of the endodontic treatment.

According to Ingle JI et al., 58% failure rate of the root canal treatment occurs due to incomplete obturation.[5]

In practice, the use of a solid core with sealer leaves two interfaces along which leakage could occur: the core–sealer and dentin–sealer interfaces. Thus, an adequate sealing ability between the sealer with both dentin and the core material is therefore desirable.[6]

Zinc oxide–eugenol, the most commonly used sealer, has irritating effects on oral tissue, its higher concentration is more cytotoxic due to eugenol, and it lacks adequate bonding to root canal dentin.[7] Removal of eugenol from mixture greatly reduces the toxicity. To overcome its drawbacks, an attempt has been made to replace eugenol with Aloe vera gel and to improve sealer bonding to root canal dentin. This is the first study to use zinc oxide–Aloe vera as a root canal sealer in endodontics.

The Aloe vera plant has been known for its medicinal properties. The name “Aloe Vera” is derived from the Arabic word “Alloeh,” meaning “shining bitter substance” and “vera” in Latin means “true.” It comes from the family “Asphodelaceae” genus “Aloe.” The most common is Aloe Vera Barbadensis, which is very popular due to its healing properties. The aloe leaf can be divided into two major parts, namely the outer green rind, including the vascular bundles, and the colorless inner parenchyma containing the aloe gel which contains clear, viscous liquid.

Aloe vera gel consists of 98.5%–99.5% water with rest containing solids of more than 200 different components, among that polysaccharides being the most abundant compounds. Other chemical compounds which are present in Aloe vera includes soluble sugars, glycoproteins, phenolic anthraquinones, flavonoids, enzymes, minerals, essential, and non-essential amino acids, sterols, saponins, and vitamins.[8]

Aloe vera has “Antrokinon” as one of the active ingredients that are known to have antivirus, antibacterial, and anticancer effect with minimal cytotoxicity. It has antibacterial property against both Gram-positive and Gram-negative bacteria. Streptococcus pyogenes, Streptococcus faecalis, Candida albicans, and Pseudomonas aeruginosa have been inhibited by Aloe vera gel.

In addition, it has analgesic property by reducing prostaglandin E2 production from arachidonic acid by inhibiting cyclooxygenase pathway, thus expecting to reduce postendodontic pain.[9] It contains antioxidants, which promotes a strong immune system, and mannose-6-phosphate, a major polysaccharide in Aloe vera gel, has a role in better wound healing and anti-inflammatory activity.[10],[11]

Hamman JH studied the composition and applications of Aloe vera leaf gel and concluded that biological activities could be attributed to polysaccharides found in the leaf gel which includes promotion of wound healing, antifungal activity, antidiabetic, anti-inflammatory, anticancer, immunomodulatory, and gastroprotective properties.[12]

According to Moghaddasi SM et al. effective components for wound healing may be tannic acid and a type of polysaccharide. Aloe vera contains Glucomannan which is a polysaccharide rich in mannose, and a plant growth hormone gibberellin interacts with growth factor receptors present on the fibroblast thereby stimulating its activity and proliferation which in turn significantly increase collagen synthesis subsequently improve wound healing. Thus, it has adequate biocompatibility.[13]

Advantages of Aloe vera are being readily available, less expensive, sticky in nature, no adverse effects and applicable with minimal equipment. It has been used as a lubricant during biomechanical preparation in root canal treatment and as a sedative dressing.[14] It also has a soothing effect similar to eugenol.[15],[16]

Khairwa A et al., in an in vivo study, clinically and radiographically evaluated zinc oxide with Aloe vera as an obturating material in pulpectomy and concluded that such teeth showed no signs of abscess, mobility, and pain.[17]

Parthasarathy G et al. studied first time biosynthesized nanoformulation of zinc oxide–Aloe vera and their characterization of antibacterial activities against multiple pathogens and found that ZnO nanoparticles showed better activity against Staphylococcus aureus and Salmonella typhi than the other organisms.[18]

In the present study, zinc oxide–Aloe vera has been used as a root canal sealer to evaluate its sealability with root canal dentin using SEM analysis. Though studies were reported clinical use of Zinc oxide - Aloe vera as an obturating material during pulpectomy in deciduous teeth.[17] This is the first in vitro study to use zinc oxide–Aloe vera as a root canal sealer in endodontics and evaluating its sealing ability in permanent teeth.

Being sticky in nature, it is expected that Aloe vera gel being mixed with zinc oxide adheres better to the walls of dentin as compared to conventional zinc oxide–eugenol as sealer. This may contribute to better seal and hence better results.

In many studies, dye penetration method was used for the assessment of microleakage; however, there are certain limitations for traditional dye leakage methods such as dissolution during the process, and it is also difficult to observe the maximum dye penetration depth. Hence, in the present study, SEM examination was used to measure the microleakage formed between the root canal obturating material and the walls of root canal dentin. It should be noted that SEM examination is a suitable method for the assessment of interface between obturating material and root canal dentin because of its high magnification and good resolution. The usage of SEM technology in endodontics allows visualization of root/dentin structures, with different heights, without altering the focus.[19]

The aim of the present study is to evaluate the sealability of zinc oxide–Aloe vera, as a root canal sealer by in vitro SEM analysis.

In the present study, the microleakage at the interface of zinc oxide–eugenol in Group 1 and zinc oxide–Aloe vera in Group 2 with the root canal dentin was measured using ImageJ software from SEM images at at 500X, 2000X, and 6000X magnifications [Figure 2]; the mean values and standard deviation were estimated from the obtained result using SPSS version 20 and are tabulated in [Table 1]. The mean microleakage value for zinc oxide–eugenol group was 48.12 at 500X, 51.99 at 2000X, and 41.50 at 6000X, whereas for zinc oxide–Aloe vera group, it was 34.45 at 500X, 30.12 at 2000X, and 25.05 at 6000X magnification.

The results of the present study were put to statistical analysis using Student's t-test to compare their sealing ability. The mean microleakage value of zinc oxide–Aloe vera is significantly less than that of conventional zinc oxide–eugenol [Figure 3].

Thus, there was a statistically significant difference noted between zinc oxide–eugenol and zinc oxide–Aloe vera at 500X,2000X,6000X; P ≤0.05 using t-test [Table 1]. Thus, less microleakage is observed at the interface of zinc oxide–Aloe vera and root canal dentin subsequently adequate adherence of zinc oxide–Aloe vera with walls of the root canal dentin.

The findings of the present study concur with those established by Garg N et al. who found that zinc oxide–eugenol sealer gives more microleakage compared to the calcium hydroxide-based sealer (Metapex), Glass ionomer root canal sealer (Ketac Endo), and epoxy resin root canal sealer (AH Plus).[20]

Singh CV et al. in their respective studies have also shown that zinc oxide–eugenol sealer gives more microleakage compared to the AH plus and Resino Seal under SEM analysis.[21]

Limitation of the present study is that the sealing ability of zinc oxide–Aloe vera was compared only with conventional zinc oxide–eugenol sealer. Further in vitro studies should be conducted to compare its sealing ability with other resin-based sealer and bioceramic sealer.

Hence, it can be stated that zinc oxide–Aloe vera can be considered as an alternative to zinc oxide–eugenol as a root canal sealer to obtain better sealability with minimal cytotoxicity. Better sealability may be attributed due to the sticky nature of Aloe vera gel.

 Conclusion



Thus, within the limitations of this study, it was concluded that zinc oxide–Aloe vera provides the superior seal when compared with conventional zinc oxide–eugenol. In addition, it has analgesic, anti-inflammatory, and wound healing property with good biocompatibility. Thus, its use as a sealer can enhance the success of the endodontic treatment. This is the first in vitro study to use zinc oxide–Aloe vera as a root canal sealer in endodontics. Further in vitro and in vivo studies should be conducted to know about the type of bonding occurred, i.e., chemical or micromechanical, and other physicochemical properties of zinc oxide–Aloe vera including flow, pH change, working time, setting time, pushout bond strength, dimensional change, solubility, and film thickness to make its use successfully as a root canal sealer.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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