|Year : 2020 | Volume
| Issue : 2 | Page : 76-80
Dentinal element incorporation, interfacial adaptation, and pH change induced by bioceramic sealer, mineral trioxide aggregate-based sealer, and epoxy resin-based sealer – An in vitro, scanning electron microscopy electron probe X-ray microanalysis study
Vibha R Hegde, Nikita J Arora
Department of Conservative Dentistry and Endodontics, YMT Dental College, Navi Mumbai, Maharashtra, India
|Date of Submission||24-Dec-2018|
|Date of Decision||12-Apr-2019|
|Date of Acceptance||03-Aug-2019|
|Date of Web Publication||18-Jun-2020|
Nikita J Arora
B - 2603, Omkar Veda, Eknath Ghadi Marg, Parel, Mumbai - 400 012, Maharashtra
Source of Support: None, Conflict of Interest: None
Aim: Comparative evaluation of Dentinal Element Incorporation, Interfacial Adaptation, and pH change induced by Bio-ceramic Sealer, mineral trioxide aggregate (MTA)-based sealer, and Epoxy Resin-based sealer.
Materials and Methods: Freshly extracted eighty mandibular premolar teeth were divided into four groups (n = 20) based on the sealer used for obturation, i.e., AH Plus (Group I), Endoseal MTA (Group II), EndoSequence BC Sealer (Group III), or Unfilled, unimmersed (Group IV), which served as the control. Specimens of Group I, II, and III were immersed in calcium and magnesium-free phosphate-buffered saline for 7 days. Specimens were sectioned longitudinally, and the ultrastructure of the dentine material interface and the elemental incorporation in the interfacial layer was analyzed using a wavelength dispersive scanning electron microscope-X-ray spectroscopy electron probe microanalyzer (SEM). The interfacial adaptation was measured using SEM. pH was calculated using pH meter.
Statistical Analysis: Data were statistically analyzed using one-way ANOVA and Duncan's multiple range tests.
Results: At the interface, both bio-ceramic materials formed a tag-like structure rich in calcium and silicon deposits, which were significantly higher in EndoSequence and Endoseal MTA, respectively. Endosequence BC sealer showed fewer interfacial gaps and the highest pH change as compared to the other groups.
Conclusions: Bio-ceramic sealers showed better interfacial adaptation, element incorporation in the interfacial layer, and increased alkalinity of pH, leading to a superior marginal seal as compared to AH Plus and the control group.
Keywords: Bioactive materials, bio-ceramics, endoseal mineral trioxide aggregate, Endosequence BC sealer, interfacial adaptation
|How to cite this article:|
Hegde VR, Arora NJ. Dentinal element incorporation, interfacial adaptation, and pH change induced by bioceramic sealer, mineral trioxide aggregate-based sealer, and epoxy resin-based sealer – An in vitro, scanning electron microscopy electron probe X-ray microanalysis study. Endodontology 2020;32:76-80
|How to cite this URL:|
Hegde VR, Arora NJ. Dentinal element incorporation, interfacial adaptation, and pH change induced by bioceramic sealer, mineral trioxide aggregate-based sealer, and epoxy resin-based sealer – An in vitro, scanning electron microscopy electron probe X-ray microanalysis study. Endodontology [serial online] 2020 [cited 2020 Oct 24];32:76-80. Available from: https://www.endodontologyonweb.org/text.asp?2020/32/2/76/287066
| Introduction|| |
Endodontic sealers are used widely to improve the physical, chemical, and biological properties of the interfacial layer. Thereby reinforcing the “monoblock concept,” in which the core material, sealing agent, and the root canal dentine form a single cohesive unit. This improves the interfacial adaptation of the material to the dentinal walls, thereby reducing microleakage and increasing root strength.
Hench described a bioactive material as one that elicits a specific biological response at the interface of the material, which results in the formation of a bond between the tissues and the material. They are being widely used in the field of medicine and dentistry specifically for the purpose of regeneration, repair, and reconstruction of dental tissues but have recently been introduced as endodontic sealers as well.
EndoSeal mineral trioxide aggregate (MTA) (Maruchi, Wonju, Korea), a premixed pozzolan-based MTA sealer, is a preloaded material confined into an airtight syringe that permits its direct application into the root canals., The performance of MTA can be largely attributable to its bioactivity.,,, Han and Okiji, in 2011, demonstrated, intertubular calcium and silicon incorporation and formation of a tag-like structure by MTA in the presence of phosphate-buffered saline (PBS). This bio-mineralization property leads to good sealing ability and the dentine bonding of this material. Another bio-ceramic sealer, EndoSequence BC (Brasseler USA, Savannah, GA) is popularly being used, which forms hydroxyapatite and, ultimately, a bond between dentine and filling material as well., EndoSequence BC Sealer is a premixed bio-ceramic endodontic sealer, the components of which are similar to MTA with the addition of monobasic calcium phosphate. According to studies by Loushine et al. and Zhang et al., it demonstrates a number of favorable properties like good sealing ability, bio-compatibility, antibacterial activity, and dentine adhesion.,,
Hotta et al. stated that dentine may uptake several elements released from bioactive materials, and such a phenomenon may cause chemical and structural dentine modification resulting in the acquisition of higher acid resistance and remineralization. Properties such as calcium releasing ability, pH, and apatite-forming ability, are thought to be useful for predicting the bioactivity for such sealers.
This study hence attempts to evaluate the dentinal calcium and silicon uptake, interfacial adaptation, and pH change induced by Bio-ceramic Sealer and MTA Based sealer comparing it to the current gold standard epoxy resin-based sealer.
| Materials and Methods|| |
Freshly extracted intact human mandibular premolars (for orthodontic purpose) without caries, with anatomically similar roots, were selected. The teeth were examined with a stereomicroscope under × 10 magnification to detect craze lines or cracks, which were excluded from the study, resulting in 80 specimens. Teeth were stored in 0.1% thymol solution and were decoronated at the cementoenamel junction with a diamond-coated saw (Isomet 2000; Buehler Ltd., Lake Bluff, Illinois, USA). The roots were adjusted to 15 mm in length, and the working length was established 1 mm short of the apex. All the root canals were instruments using Protaper Universal rotary instruments till size F3 using crown-down technique under copious irrigation with 5 ml of 2.5% sodium hypochlorite (NaOCl). Canals were rinsed with 2 ml of 17% aqueous ethylenediaminetetraacetic acid for 1 min followed by distilled water as the final irrigant to remove any traces of remnant NaOCl and dried using paper points (Protaper ® Universal Paper Points).
Samples were randomly divided into the following four groups (n = 20 in each group) according to the type of sealer used.
- Group I: Obturated using Gutta Percha with AH Plus sealer (DeTrey Dentsply, York, Pennsylvania, USA)
- Group II: Obturated using Gutta Percha with End seal MTA (Maruchi, Wonju, Korea)
- Group III: Obturated using bio-ceramic particle impregnated gutta-percha points with EndoSequence BC Sealer (Brasseler USA, Savannah, GA)
- Group IV: Served as the unfilled and un-immersed control.
Samples were then stored at 37°C and 100% humidity for 2 h to allow the initial setting of the material and then immersed in plastic vials containing 20 ml of calcium and magnesium-free PBS for 7 days. Specimens were sectioned longitudinally into two symmetrical halves.
Morphological and element analysis
The specimens were mounted on aluminum stubs, sputter-coated with a 20–25 nanometer-thick carbon layer (CAMECA SX-5 France), and analyzed using a wavelength-dispersive X-ray spectroscopy electron probe microanalyses with an image observation function scanning electron microscope-electron probe X-ray microanalysis (SEM-EPMA CAMECA SX-5 France).
For the morphological observation, the outermost dentine layers of the dentine-material interface were analyzed under SEM-EPMA at an accelerating voltage of 15 kV. Interfacial gaps were measured using SEM.
Chemical component analysis and element mapping were carried out using SEM-EPMA, 60–70 μm away from the interface.
pH of the PBS solution was measured using pH meter postimmersion of the specimens in the solution at 7 days. Results were subjected to statistical analysis.
Data obtained was presented as mean and standard deviation for all the groups and parameters. Calcium and silicon uptake, and interfacial gaps were analyzed using one-way ANOVA and Duncan's multiple range tests. The results of the above tests were considered statistically significant at P ≤ 0.05.
| Results|| |
- Scanning electron microscopic analysis [Figure 1]a, [Figure 1]b, [Figure 1]c revealed statistically significantly lesser interfacial gaps with the teeth obturated using EndoSequence BC sealer (Group III), followed by Endoseal MTA (Group II) when compared to AH Plus sealer (Group I) [Table 1]
- The EPMA studies on the interfacial dentine layer over the 7-day PBS immersion period for all the groups are shown in EndoSequence BC group showed a significant increase in the calcium uptake [Figure 1]d, [Figure 1]e, [Figure 1]f followed by Endoseal MTA specimens when compared with those of the AH Plus group and the control (P < 0.05, one-way ANOVA and Duncan's test). Moreover, silicon [Figure 1]g, [Figure 1]h, [Figure 1]i percentage was significantly increased in the Endoseal MTA group with time, while only traces were detected in the control specimens [Table 2]
- The pH meter revealed significantly highest pH change with EndoSequence BC, followed by Endoseal MTA when compared to the AH plus group [Table 1]
- Results of all the parameters have been graphically represented in [Graph 1] and [Graph 2].
|Figure 1: (a-c) Scanning electron microscope images of interfacial gaps of AH Plus, Endoseal mineral trioxide aggregate, EndoSequence BC sealer. (d-f) Electron Probe Microanalyzer images of calcium uptake in AH Plus, Endoseal mineral trioxide aggregate, EndoSequence BC. (g-i) Of silicon uptake in AH Plus, Endoseal mineral trioxide aggregate, EndoSequence BC, respectively|
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|Table 1: Scanning electron microscope analysis of interfacial gaps and pH change use pH meter|
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|Table 2: Electron probe microanalyzer evaluation of calcium and silicon uptake at the interface between sealer and dentine|
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| Discussion|| |
The present results indicate significantly better interfacial adaption with EndoSequence BC sealer, followed by Endoseal MTA and was least in the AH Plus group. EndoSequence BC group showed lowest interfacial gaps, probably due to the chemical bonding of the sealer to the dentinal walls as well as the bio-ceramic particle impregnated gutta-percha points. Better interfacial adaption of both the bio-ceramic sealers can be attributed to the formation of the interfacial layer. The results are in accordance with Sarkar et al., who suggested that in the presence of phosphate-containing fluids, apatite formation takes place due to the release of calcium and hydroxyl ions. This promotes controlled mineral nucleation on dentine and results in the formation of a tag-like interfacial layer.
In the current study, calcium uptake was seen post-PBS immersion in both EndoSequence BC and Endoseal MTA groups, which represents the biomineralization ability of these calcium silicate materials promoted by the interaction with dentine in the presence of phosphate-containing solutions.,, Results are in accordance with the study conducted by Cinder et al., which showed that the amount of calcium released from EndoSequence BC Sealer was far higher than that from AH Plus, mainly after 7 days. The increased calcium release could be due to the setting reaction of bio-ceramic, i.e., hydration reactions of calcium silicate.
On the other hand, Endoseal MTA also showed a statistically significant increase of silicon in the interfacial layer. The silicon-rich layer was constantly narrower than the calcium-rich layer in the EndoSequence BC sealer group. Carlisle in 1970 stated that the precise role of silicon in hard tissue metabolism remained unclear, although it was believed to play a role in the early bone calcification process. In 2002, Patel et al. demonstrated the role of silicon in enhancing the rate of new bone growth when released from bioactive materials. Moreover, Saito et al. reported that silicon induces remineralization of demineralized dentine. These findings suggest that the release of silicon from such materials may be suggestive of additional bioactivity of these materials.
In the EndoSequence BC group, the pH of PBS was altered to the most alkaline level when compared to Endoseal MTA and AH Plus groups. This could be due to a concordance between the pH and amount of calcium released by the bio-ceramic materials, as observed by Candeiro et al. in their study. Alkaline pH promotes the elimination of bacteria such as Enterococcus faecalis that might survive after chemomechanical preparation and induce or maintain periapical inflammation but do not survive in pH near 11., It has been suggested that the mechanism of repair stimulation by deposition of mineralized tissue depends on pH and on the ability to release calcium., Alkaline nature of bio-ceramic by-products tends to denature dentinal collagen fibers, facilitating the penetration of sealers into the dentinal tubules, thereby enhancing interfacial adaptation.
Taking into account all the above findings, we can conclude that bioactive materials have been demonstrating superior clinical properties and hence are being widely used in endodontic practice today.
| Conclusions|| |
- Bio-ceramic sealers showed better interfacial adaptation, element incorporation in the interfacial layer, and increased alkalinity of pH, leading to a superior marginal seal as compared to AH Plus and the control group
- EndoSequence BC proved to be more promising in terms of Calcium release and pH change and demonstrated less interfacial gaps while silicon uptake was highest with MTA Endoseal
- Future long-term evaluation of interfacial adaptation and microleakage with these bioactive materials is the need of the hour.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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