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- Physicochemical Properties of Epoxy Resin-Based and Bioceramic-Based Root Canal Sealers
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Heat sealer - Wikipedia
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F.A.Q. (Frequently Asked Questions)
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When moisture evaporates the white haze of efflorescence becomes visible. It is a condition in all cement based products and although the condition may be minuscule or severe, it usually corrects itself overtime with exposure to the environment. How do you clean Efflorescence? Why, after sealing, does the surface turn white?
If the sealer is applied when the surface is wet. It appears to be dry but still contains moisture in the stone or sand joints.
Over time an over-accumulation of sealer has built up a thick coat. This thick coat does not allow moisture to escape causing the moisture to trap between the surface and the sealer. Water or moisture is trapped beneath the stone and base. How do you solve this problem of whitening or blushing? Apply over tainted area with roller or pump sprayer. The tainted sealer will disappear. Repeat process if necessary. Among the clinically available root canal sealers, epoxy resin-based sealers are widely used for root canal filling due to their resorption resistance and dimensional stability [ 4 — 6 ].
Most recently introduced bioceramic-based materials have attractive physical, chemical, mechanical, and biological properties [ 10 , 11 , 17 ]. Therefore, the representative 3 epoxy resin-based sealers and 3 bioceramic-based sealers were compared for physical and chemical properties, in this study. The flow of endodontic sealers may have an effect on obturation of accessory canals and microspaces between master and accessory cones [ 3 ]. Various factors such as composition, shear rate, particle size, temperature, and time from mixing are related to the flowability of sealers [ 3 ].
Setting time is also important to provide adequate working time and proper consistency enough to fill the root canal system completely [ 20 ]. Setting times of evaluated sealers in this study were different from that given by the manufacture. Only AH-Plus was in agreement with the ISO standards and it showed a significant higher mean setting time value, almost 8 times greater than the other epoxy resin-based root canal sealers.
AH-Plus is comprised of base and catalyst in which a slow polymerization reaction of epoxy resin amines with a high molecular weight including bisphenol A and bisphenol F occurs [ 21 ]. This chemical composition could explain significantly higher setting time of it.
On the other hand, Radic-Sealer and AD Seal are the kind of resin composites containing a catalyst component that accelerates the process [ 22 ]. In the meanwhile, BC Sealer and MTA Fillapex were not set in humid incubator condition, and this result was different from several reports that final setting of these materials occurred [ 4 — 6 , 10 , 23 , 24 ].
Depending on Loushine et al.
Physicochemical Properties of Epoxy Resin-Based and Bioceramic-Based Root Canal Sealers
However, the authors concluded that overly wet canals may affect the setting time and, in particular, adversely affect the microhardness of the sealer after setting [ 10 ]. They also pointed out that a more porous matrix would be present when the sealer sets in the wet canals, which, in turn, may result in increased leaching of tissue-irritating substances from the sealer [ 10 ]. The delayed setting time of sealers may also affect biocompatibility and the sealers may have the potential to release cytotoxic byproducts before the final setting [ 10 ].
These findings are in agreement with other previous studies [ 25 , 26 ] that showed strongly affected cell viability with MTA Fillapex. Radiopacity is an essential property of endodontic sealing materials. Among other physical, chemical, and biological properties, the ideal root canal sealing material should have a certain level of radiopacity [ 27 ]. Sufficient radiopacity allows clinicians to make a clear distinction between the materials and the surrounding anatomic structures and to evaluate the quality of the root fillings [ 28 ].
International standards require a minimal radiopacity equivalent to 3. In the present study, AH-Plus and EndoSeal MTA showed statistically higher radiopacity values , but all the tested sealers exhibited values complying with the international standards. According to Duarte et al. In this study, 4 tested sealers expanded compared to initial dimension and AD Seal had a significant increase of height i.
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This increase of mass and height presented by 3 epoxy resin-based sealers probably occurred as a result of the water absorption and a high expansion of resin-based sealers, which was also verified by Versiani et al. Dimensional change values ranging from 0. It has been demonstrated that polymerized materials from mixtures of hydrophilic monomers had high water sorption [ 33 ]. However, all the tested materials showed bigger expansion rate than the favorable rate suggested by the international standards Table 1.