|Year : 2020 | Volume
| Issue : 3 | Page : 137-141
Comparative evaluation of marginal adaptation of two resin-based sealers: A scanning electron microscopic study
Prashant Moogi, Anjum Sayyad, Vishnu Rathore, Surabhi Ghosh, Shweta Ambalia, Aditi Amin
Department of Conservative Dentistry and Endodontics, Yogita Dental College and Hospital, Ratnagiri, Maharashtra, India
|Date of Submission||29-Nov-2019|
|Date of Decision||12-Jan-2020|
|Date of Acceptance||13-Mar-2020|
|Date of Web Publication||28-Oct-2020|
Dr. Anjum Sayyad
Department of Conservative Dentistry and Endodontics, Yogita Dental College and Hospital, Khed, Ratnagiri, Maharashtra
Source of Support: None, Conflict of Interest: None
Aim: The aim of the study was to evaluate the marginal adaptation of two epoxy resin-based sealers to dentin.
Materials and Methods: Forty freshly extracted human single-rooted mandibular premolar teeth with completely formed apices were selected. Teeth were decoronated, and root canals were instrumented. The specimens were divided equally into two groups: (1) Group 1 (n = 20) – Teeth obturated with gutta percha and Perma Evolution. (2) Group 2 (n = 20) – Teeth obturated with gutta percha and AH Plus sealer. Later, samples were vertically sectioned using diamond disk, and marginal adaptation of sealers was evaluated at coronal, middle, and apical halves using scanning electron microscopy, and marginal gap values were recorded.
Results: Both the sealers produced a marginal gap to a certain extent. Perma Evolution exhibited an average marginal gap of 6.02 ± 4.81, followed by AH-Plus with 6.56 ± 4.73.
Conclusion: As the marginal gaps between dentin sealers were seen to be minimum in Perma Evolution, we conclude that Perma Evolution is better adapted to root canal dentin than AH-Plus sealer.
Keywords: AH-plus, marginal adaptation, Perma Evolution, scanning electron microscope
|How to cite this article:|
Moogi P, Sayyad A, Rathore V, Ghosh S, Ambalia S, Amin A. Comparative evaluation of marginal adaptation of two resin-based sealers: A scanning electron microscopic study. Endodontology 2020;32:137-41
|How to cite this URL:|
Moogi P, Sayyad A, Rathore V, Ghosh S, Ambalia S, Amin A. Comparative evaluation of marginal adaptation of two resin-based sealers: A scanning electron microscopic study. Endodontology [serial online] 2020 [cited 2021 Dec 5];32:137-41. Available from: https://www.endodontologyonweb.org/text.asp?2020/32/3/137/299288
| Introduction|| |
One of the most important aspects for the success of the endodontic treatment is the adequate obturation of the prepared root canal space. It is generally agreed that the use of gutta-percha cones with a sealer cement is one of the most commonly used methods for filling the root canal system. These sealers act as the binding agents, which are used to adapt the rigid gutta-percha to canal walls and to fill up the voids, accessory canals, and irregularities within the canal. However, root canal sealers leak to some extent, and most leakage occurs between the root canal walls and the sealer. The ability of a sealer cement to bond to the tooth structure is, therefore, of considerable importance.
Previous investigations have assessed the sealing properties of epoxy resin sealer AH-Plus (Dentsply Maillefer, Ballaigues, Switzerland). It has been concluded that in comparison with other sealers, AH-Plus showed high bond strength to the canal wall along with long-outstanding dimensional stability.
More recently, a new epoxy resin-based material, Perma Evolution (Alfred, Becht Germany) has been introduced. Perma Evolution, a permanent root-filling material, combines trusted epoxy amine technology with innovative microcapsule technology. The product comes with integrated microcapsules containing a new reactive adhesive to make the two components material more resilient and tight. To date, no information is available on the sealing ability of Perma Evolution when used as a sealer cement.
Therefore, the purpose of this in vitro scanning electron microscopic study was to determine the marginal adaptation of two epoxy resin sealers, Perma Evolution and AH-Plus, to the root canal dentin at the coronal, middle, and apical third regions of the root canal.
| Materials and Methods|| |
Forty single-rooted human permanent mandibular premolars extracted for periodontal or orthodontic cause were selected for the study. The teeth were ultrasonically cleaned of debris and soft-tissue remnants and were stored in 0.1% thymol solution until further use. All the samples were then sectioned at the cementoenamel junction with a low-speed diamond disc (Dfs, Germany), and a root length of 12 mm was standardized.
Instrumentation was done in crown-down technique using Dentsply Maillefer (Ballaigues, Switzerland) up to F3. Simultaneously, the canals were irrigated with 5.25% Sodium Hypochlorite (Prime Dental Products Pvt Ltd), 17% ethylenediaminetetraacetic acid (EDTA-Meta Biomed Co. Ltd), and finally rinsed with saline and dried with sterile paper points (Dentsply Maillefer). Then, the teeth were divided randomly into two experimental groups based on the sealers used.
- 1 – Canals obturated with gutta percha and Perma Evolution (Alfred, Becht Germany)
- Group 2 – Canals obturated with gutta percha and AH Plus (Dentsply Maillefer, Ballaigues, Switzerland)
Group 1 (Perma Evolution, Alfred, Becht Germany).
The sealer was mixed using a self-mixing tip attached to a syringe. Then, the sealer was applied to root canal space using Lentulo spiral (Mani Prime Dental), and corresponding protaper gutta-percha point coated with sealer was inserted to the working length. Cone was then seared off at orifice level using touch and heat (Sybron Endo).
Group 2 (AH Plus Dentsply Maillefer, Ballaigues, Switzerland).
As per the manufacturers' instructions, the sealer is mixed. After thorough drying of canals, the sealer was applied in the canal using Lentulo spiral and corresponding protaper gutta-percha points coated with the sealer and seared off at the level of orifice using touch and heat (Sybron Endo).
Obturated teeth were stored at 37°C and 100% humidity for 7 days. Each root was then longitudinally sectioned using a diamond disc on a slow-speed handpiece to obtain the dentin-root canal-filling interface. During sectioning, the specimens were subjected to continuous water cooling to prevent frictional heat.
All specimens were dehydrated in an ascending series of aqueous ethanol (70%, 80%, 90%, 95%, and 100%); gold sputtered, and observed under scanning electron microscopy (SEM) using high-accelerating voltage of 15.0 kV at different magnifications ranging from ×25 to ×2000 to achieve a representative area containing both gap-containing and gap-free regions and visualize a broader aspect of sample.
Under SEM, two to three random areas from coronal middle and apical third of each sample were focused, and dentin-sealer interfacial gaps were measured using software ImageJ software (Wayne Rasband; National Institute of Health, Bethesda, MA, USA). Overall, average gaps at this interface were calculated for each sample.
Descriptive statistics were expressed as mean ± standard deviation (SD) for each group and subgroups for distance.
Two groups were compared for distance at various levels (coronal middle and apical) by unpaired t-test.
All the three (coronal middle and apical) were compared among Group 1 and Group 2 by analysis of variance, followed by pair-wise comparison by Tukey's post hoc test.
For all the above tests, P value is considered statistically significant when it was <0.05.
The software used was the Statistical Package for the Social Sciences version 17.
| Results|| |
The mean ± SD for gap formation for Group 1 was 12.08 ± 3.52, 2.83 ± 1.03, and 3.14 ± 0.69 at coronal, middle, and apical third, respectively [Table 1].
|Table 1: Summary statistics of coronal, middle, and apical values (nm) in Groups 1and 2|
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The mean ± SD for gap formation for Group 2 was 11.82 ± 4.88, 3.48 ± 0.72, and 4.39 ± 1.00 at coronal, middle, and apical third, respectively [Table 1].
In Group 1, a maximum gap of 18.45 was seen at coronal level, whereas least gap was seen at the middle level, i.e., 4.85 [Table 1].
In Group 2, maximum gap was seen at coronal level, i.e., 19.96, whereas the minimum gap was seen at the middle third, i.e., 4.68 [Table 1].
According to the results obtained, it can be concluded that Group 1 showed maximum gap at coronal level as compared to Group 2 [Graph 1], whereas at the middle and apical third, Group 2 showed more gap as compared to Group 1 [Graph 1].
Hence, it can be concluded that the marginal adaptation of Group 1 is superior as compared to Group 2 [Table 2] and [Figure 1], [Figure 2].
|Figure 1: Scanning electron microscopy images Group 1; dentin-sealer interface at × 2000 (a) marginal gaps are seen at the coronal third (b) middle third (c) apical third|
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|Figure 2: Scanning electron microscopy images Group 2; dentin-sealer interface at × 2000 (a) marginal gaps at the coronal third (b) middle third (c) apical third|
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| Discussion|| |
Successful root canal therapy requires complete obturation of the root canal space along with impervious seal. A fluid-tight seal is the main requisite to achieve a successful obturation. Nowadays, the use of a solid or a semi-solid core such as gutta-percha along with sealer is a commonly employed method of obturation. Because of the hydrophobic nature of gutta-percha, the sealer tends to pull away from gutta-percha on the setting. Hence, microscopic gaps between the sealer and dentin and sealer and core obturating material are seen which jeopardize the outcome of root canal treatment, and marginal leakage through these gaps continues to be a major reason for the failure of root canal therapy. As the gutta percha is devoid of any adhesive properties, sealers help to adapt the same to the root canal dentin.
Several types of endodontic sealers have been recommended to achieve this goal which includes silicon-based sealers, epoxy resin-based sealers, mineral trioxide aggregate-based sealer, calcium silicate-phosphate-based bioceramic sealer, and methacrylate resin-based sealer. Epoxy resin-based sealers showed reduced solubility, better apical seal, and micro retention to root canal dentin. Lee et al. compared the sealing ability of bioceramic sealer Endosequence and AH Plus using a scanning electron microscope and micro computed tomography, and no statistical difference was seen between the two. Although AH Plus has shown better results as compared to other sealers, a quest for an alternative still continues. Hence, this study compares and evaluates the marginal adaptation of AH-Plus which is proved to have better marginal adaptation and newer sealer Perma Evolution to root canal dentin.
Among all the tested groups, Perma Evolution sealer showed better marginal adaptation in the apical third and minimal gaps. Better performance of the Perma Evolution can be attributed to trusted epoxide chemistry technology with added benefit of microcapsule technology. As the product comes with integrated microcapsules containing a new reactive adhesive, it makes the two components material more resilient and tight which helps in better marginal adaptation of the sealer to root dentin. Furthermore, the tight adhesion to dentin may be due to the hydrophilic formulation of the sealer.
In the present study, the AH Plus had a good adaptation at the coronal third than the middle and apical third because of its low particle size and film thickness which is in the range of 20–25 μm. The low solubility of AH Plus on exposure to tissue fluids aids in better penetration. The adaptation of AH Plus to dentin is due to its flow and long setting time. However, this group exhibited greater mean marginal gap at the middle and apical third when compared to Perma Evaluation group which could be due to linear setting shrinkage of 0.034% ± 0.01% in AH Plus. The results of the present study were in agreement with those of previous studies conducted by Borges et al. and Pius and Mathew.
In this study, single-canal mandibular premolars were selected because they have approximately similar buccolingual and mesiodistal dimensions to eliminate variations in dimensions, and also they were decoronated at the cementoenamel junction to eliminate variations in access cavity preparation.
Instrumentation of all samples was done using NiTi rotary instruments (ProTaper) up to F3 to avoid thinning of the root dentin. Before obturation of the root samples, irrigation was done with 5 ml of 2.5% NaOCl solution and 5 ml of 17% EDTA solution, respectively, because any remaining sodium hypochlorite might inhibit the setting of the resin-based materials. In addition, EDTA flows easily into the dentinal tubules because of its low surface tension. Thus removes the smear layer up to a depth of 2.5–4 μm  which, in turn, increases the adaptation of the sealer to the root dentin.
Single-cone obturation technique was used in this study to avoid excessive dentin removal required to facilitate the plugger's insertion during vertical compaction and the wedging forces of the spreader's during lateral compaction.
Many studies have been evaluated to assess the sealing ability of the endodontic sealers through various methods such as dye penetration method, electrical methods, fluid filtration technique, radioisotope tracing, and SEM. The advantage of using SEM over various methods is that in SEM, the defects at the submicron level can be observed at required magnification, and a final evaluation can be done by preserving microphotographs.
In the present study, it was seen that both the sealers showed marginal gaps at the coronal, middle, and apical third of the root canal. Maximum gap was seen at the coronal third, followed by apical third and middle third. This may be due to sectioning of the filled canal which may result in dislodgement of the material and also smearing of gutta-percha that may hide the areas of sealer In the apical third, smear layer plays a major role in the penetration of root canal sealers. The presence of the smear layer may result in improper adaptation of sealer to the root dentin. Furthermore, uniform application of sealer is difficult in the apical third of the canal resulting in gap formation. At the coronal third, AH-Plus showed better adaptation as compared to Perma Evolution. At the same time, in the middle and apical third, Perma Evolution exhibited better marginal adaptation between the two.
It is unlikely, however, that the sealing failure we observed in both materials resulted solely from problems inherent in the sealers or the obturating technique per se. Other factors, such as the possible presence of smear layer and entrapped air at the interface, accessory canals, fins or oval-shaped canals that are difficult to prepare, and fill adequately may be also responsible for sealing failure.
| Conclusion|| |
Under the conditions of this in vitro study, it has been concluded that:
- None of the groups showed complete marginal adaptation at dentin–sealer interface. There were both gap-free and gap-containing regions at different levels in all groups
- There was a significant difference in marginal adaptation between Group 1 and Group 2
- SEM observation showed that the mean marginal gap in Group 1 is 6.022 ± 4.81 and in Group 2 is 6.56 ± 4.74 [Table 2]
- In the coronal third, AH Plus exhibited better marginal adaptation to dentin than Perma Evolution
- However, under the limitations of the present study, it can be concluded that Perma Evolution showed better marginal adaptation in the middle and apical third as compared to AH Plus.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]