Fracture toughness testing: A discriminatory mechanical testing performance indicator for glass-ionomer restoratives?

Baig, Mirza Shahzad; Lloyd, C.H.; Fleming, Garry J.P.

doi:10.1016/j.dental.2015.04.014

Cited by 7 publications

(3 citation statements)

References 48 publications

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“…With respect to incorporation of fiber in GIC powders, the aspect ratio (fiber length:diameter), chemical composition, reinforcing fiber fraction, composition of the GIC powder and liquid, and the powder:liquid mixing ratios employed were markedly different for the studies reporting fiber reinforcement of GICs, such that a direct comparison under controlled conditions was not possible. On the other hand, this study confirms that the mean fracture toughness and compressive strength values reported for the commercial GIC without reinforcement are within the range of data previously reported . However, studies have been published reporting higher values of compressive strength for commercial conventional GICs than those obtained in the present study .…”

Section: Discussionsupporting

confidence: 92%

Incorporation of cellulose fiber in glass ionomer cement

Garoushi

Obradovic

et al. 2020

European J Oral Sciences

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This study investigated the effect of discontinuous cellulose microfibers with various loading fractions on selected physical properties of glass polyalkenoate (glass ionomer) cement (GIC). Fiber‐reinforced GIC (Exp‐GIC) was prepared by adding discontinuous cellulose microfiber (with an average length of 500 μm) at various mass ratios (1, 2, 3, 4, and 5 mass%) to the powder of conventional GIC (GC Fuji IX) using a high‐speed mixing device. Fracture toughness, work of fracture, and compressive strength were determined for each experimental and control material. The specimens (n = 6) were wet stored (37°C for 1 d) before testing. A scanning electron microscope equipped with an energy dispersive spectroscope was used to examine the surface of fibers after treatment with cement liquid. Data were analyzed using ANOVA. The Exp‐GIC (5 mass%) specimen had statistically significantly higher fracture toughness (0.9 MPa.m1/2) than unreinforced material (0.4 MPa.m1/2). On the other hand, Exp‐GIC with 1 mass% displayed the highest compressive strength (116 MPa) among all tested groups. The use of discontinuous cellulose microfibers with conventional GIC matrix considerably increased the toughening performance compared with the particulate GICs used.

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Section: Discussionsupporting

confidence: 92%

Incorporation of cellulose fiber in glass ionomer cement

Garoushi

Obradovic

et al. 2020

European J Oral Sciences

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“…In particular, K IC data may provide an enhanced understanding regarding the extent of polymer entanglement which, in addition to the ionic crosslinks, is a key contributor the mechanical performance of GICs. 39,65 Second, correlating K IC with changes in the ratio of evaporable to non-evaporable water in the cement over time as a function of the glass’ Si:Ge ratio would provide more conclusive evidence regarding the plasticizing effect of water on the polysalt matrix as a mechanism that contributes to the mechanical decline of Ge-containing GICs. Finally, assessing K IC of Ge-containing cements as a function of PAA M W and or concentration will determine whether or not their extended setting behavior is a practical platform to improve the toughness of GICs.…”

Section: Discussionmentioning

confidence: 99%

Exploring the unexpected influence of the Si:Ge ratio on the molecular architecture and mechanical properties of Al-free GICs

2016

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Germanium (Ge)-based glass ionomer cements have demonstrated the ability to balance strength with extended setting times, a unique set of characteristics for aluminum-free glass ionomer cements. However, the mechanical properties of current Ge-based glass ionomer cements significantly deteriorate over time, which jeopardizes their clinical potential. This work explores the effect of incrementally decreasing the Si:Ge ratio in the glass phase of zinc-silicate glass ionomer cements to identify potential mechanisms responsible for the time-induced mechanical instability of Ge-based glass ionomer cements. The influence of Ge was evaluated on the basis of changes in mechanical properties and molecular architecture of the cements over a 180-day period. It was observed that the compressive strength and modulus of the cements were sustained when Si:Ge ratios were ≥1:1, but when Si:Ge ratios are <1:1 these properties decreased significantly over time. These mechanical changes were independent of structural changes in the glass ionomer cement matrices, as the level of metal-carboxylate crosslinks remained constant over time across the various Si:Ge ratios explored. However, it was noted the temporal decline of mechanical properties was proportional to the increased release of degradation byproducts, in particular Ge that was released from the cements in substantially greater quantities than other glass constituents. Unexpectedly, the slowest setting cement (Si:Ge 1:1) was also the strongest; behavior that is uncommon in Si-based glass ionomer cements, supports the potential of Ge-containing glass ionomer cements as injectable bone cements in applications such as percutaneous vertebroplasty.

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“…Glass ionomer cements (GICs) are popular direct aesthetic restorative materials used in non-stress bearing regions [ 8 ], due to long-term fluoride release [ 9 ] and physiochemical adherence to tooth structure [ 10 ]. Furthermore, GICs are biocompatible with oral tissues [ 11 , 12 ], have excellent bioactivity [ 3 , 13 ], low cytotoxicity [ 7 ] and a similar coefficient of thermal expansion to that of tooth structure (dentin) [ 14 ]. To minimize polymerization shrinkage in large restorations, a substantial part of dentin is recommended to be replaced with GIC prior to the placement of resin composite.…”

Section: Introductionmentioning

confidence: 99%

Microtensile bond strength of glass ionomer cements to a resin composite using universal bonding agents with and without acid etching

Farshidfar

Agharokh

Ferooz³

et al. 2022

Heliyon

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To assess the effect of two universal bonding agents on the microtensile bond strength (μTBS) of encapsulated conventional glass ionomers (CGICs) and resin-modified glass ionomers (RMGICs) to a resin composite, with or without the use of 35% phosphoric acid. Methods: Four materials were used in this study: Riva Self-cure and Riva Light-cure; SDI and Equia Forte Fil and Fuji II LC; GC. The specimens were prepared in Teflon moulds with half the specimens for each GIC etched using 35% phosphoric acid (Ultra-Etch) and the remainder not etched. Each group was randomly subdivided into three groups, where the first two groups received an air-thin layer of bonding agent (G-Premio Bond ¼ GPB or Clearfil Universal Bond ¼ CUB) then light cured; and the third group had no bonding agent. For all groups, a nanohybrid composite (GC Kalore; GC) was placed incrementally on the GIC. Following 24 h immersion in distilled water, each block was embedded in epoxy resin in a cubic mould and sectioned by a cutting device. The stick specimens were then subjected to μTBS testing. Results: The application of both universal bonding agents significantly enhanced the μTBS of all GICs (p < 0.001). Both RMGICs exhibited higher μTBS compared to that of CGICs (p < 0.001). The application of universal bonding agents with acid etching significantly increased the μTBS of both CGICs and RMGICs to resin composite in contrast to without acid etching. Conclusion: Using 35% phosphoric acid for 15 s prior to the application of universal bonding agents improved the μTBS of GIC to resin composite.Clinical significance: Using Universal bonding agents with 15 s acid etching may increase the bond strength of both CGICs and RMGICs to resin composite when utilising the sandwich technique.

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Fracture toughness testing: A discriminatory mechanical testing performance indicator for glass-ionomer restoratives?

Cited by 7 publications

References 48 publications

Incorporation of cellulose fiber in glass ionomer cement

Incorporation of cellulose fiber in glass ionomer cement

Exploring the unexpected influence of the Si:Ge ratio on the molecular architecture and mechanical properties of Al-free GICs

Microtensile bond strength of glass ionomer cements to a resin composite using universal bonding agents with and without acid etching

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