The effect of composition and annealing on the properties of aluminum free GPCs: A preliminary evaluation

Dickey, Brett; Lee, Amanda; Zhang, Xiao Fang; Boyd, Daniel

doi:10.1016/j.matlet.2014.05.025

Cited by 8 publications

(8 citation statements)

References 15 publications

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“…Previous investigations by the authors support this hypothesis, as it was observed that reducing the Ge content in zirconia-stabilized glasses led to sustained strength of the corresponding GICs whilst maintaining extended handling characteristics. 17,48,49…”

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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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) Oxide is an inorganic compound [ 25 ] which takes the role of a network former when incorporated into an ionomer glass and is theoretically capable of isomorphically replacing Si in the network [ 26 ]. Ge had been previously incorporated into borate-based ionomer glasses (BGG) by Zhang et al [ 27 , 28 ]. There was an increase in the setting and working time (handling properties) of the GPCs formulated from these glasses as a result of Ge incorporation, as this decreases the number of non-bridging oxygens (NBOs) in the glass network decreasing the working and setting times of the GPCs [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

“…There was an increase in the setting and working time (handling properties) of the GPCs formulated from these glasses as a result of Ge incorporation, as this decreases the number of non-bridging oxygens (NBOs) in the glass network decreasing the working and setting times of the GPCs [ 29 ]. Dickey et al [ 27 , 30 , 31 ] reported on Ge-based ionomeric glasses and reported that glass reactivity decreased with Ge, ZrO 2 and Na 2 O incorporation, resulting in GPCs with extended working time (T w ) of up to 10 min, long setting time (T s ) up to 36 min, and compression strengths over 30 MPa after 30 days maturation [ 25 ]. Dickey et al [ 27 , 30 , 31 ] failed to evaluate whether these cements were injectable or not for use in vertebroplasty fixation.…”

Section: Introductionmentioning

confidence: 99%

“…Dickey et al [ 27 , 30 , 31 ] reported on Ge-based ionomeric glasses and reported that glass reactivity decreased with Ge, ZrO 2 and Na 2 O incorporation, resulting in GPCs with extended working time (T w ) of up to 10 min, long setting time (T s ) up to 36 min, and compression strengths over 30 MPa after 30 days maturation [ 25 ]. Dickey et al [ 27 , 30 , 31 ] failed to evaluate whether these cements were injectable or not for use in vertebroplasty fixation. The work herein expands partly on the current authors’ previous work on zinc (Zn) silicate-based GPCs by evaluating the effect of incrementally replacing the Zn in the glass component with Ge [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

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Incorporating Germanium Oxide into the Glass Phase of Novel Zinc/Magnesium-Based GPCs Designed for Bone Void Filling: Evaluating Their Physical and Mechanical Properties

Khader

Rodriguez

Towler

2018

JFB

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The structural role of Germanium (Ge), when substituting for Zinc (Zn) up to 8 mol % in the 0.48SiO2–0.12CaO–0.36ZnO–0.04MgO glass series, was investigated with respect to both the glass chemistry and also the properties of glass polyalkenoate cements (GPCs) manufactured from them. The Network connectivity (NC) of the glass was calculated to increase from 1.83 to 2.42 with the addition of GeO2 (0–8 mol %). Differential thermal analysis (DTA) results confirmed an increase in the glass transition temperature (Tg) of the glass series with GeO2 content. X-ray photoelectron spectroscopy (XPS) showed an increase in the ratio of bridging oxygens (BO) to non-bridging oxygens (NBO) with the addition of GeO2, supporting the NC and DTA results. 29Si magic angle spinning nuclear magnetic resonance spectroscopy (29Si MAS-NMR) determined a chemical shift from −80.3 to −83.7 ppm as the GeO2 concentration increased. These ionomeric glasses were subsequently used as the basic components in a series of GPCs by mixing them with aqueous polyacrylic acid (PAA). The handling properties of the GPCs resulting were evaluated with respect to the increasing concentration of GeO2 in the glass phase. It was found that the working times of these GPCs increased from 3 to 15 min, while their setting times increased from 4 to 18 min, facilitating the injectability of the Zn/Mg-GPCs through a 16-gauge needle. These Ge-Zn/Mg-GPCs were found to be injectable up to 96% within 12 min. Zn/Mg-GPCs containing GeO2 show promise as injectable cements for use in bone void filling.

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“…Germanium (Ge) adopts the role of a network former when incorporated into an ionomer glass, and is theoretically capable of isomorphically replacing Si in the network [ 29 ]. Germanium based glasses have previously been investigated by Dickey et al [ 30 , 31 , 32 ] who reported that glass reactivity decreased with Ge incorporation, resulting in GPCs with extended working times of up to 10 min, setting times between 14 and 36 min, and compression strengths in surplus of 30 MPa after 30 days maturation [ 30 ]. Ge was also incorporated into borate-based ionomer glasses (BGG) by Zhang et al [ 32 , 33 ] who reported that its presence increased handling properties of the resultant GPCS formulated from them [ 32 ].…”

Section: Introductionmentioning

confidence: 99%

Glass Polyalkenoate Cements Designed for Cranioplasty Applications: An Evaluation of Their Physical and Mechanical Properties

Khader

Curran

Peel

et al. 2016

JFB

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Glass polyalkenoate cements (GPCs) have potential for skeletal cementation. Unfortunately, commercial GPCs all contain, and subsequently release, aluminum ions, which have been implicated in degenerative brain disease. The purpose of this research was to create a series of aluminum-free GPCs constructed from silicate (SiO2), calcium (CaO), zinc (ZnO) and sodium (Na2O)-containing glasses mixed with poly-acrylic acid (PAA) and to evaluate the potential of these cements for cranioplasty applications. Three glasses were formulated based on the SiO2-CaO-ZnO-Na2O parent glass (KBT01) with 0.03 mol % (KBT02) and 0.06 mol % (KBT03) germanium (GeO2) substituted for ZnO. Each glass was then mixed with 50 wt % of a patented SiO2-CaO-ZnO-strontium (SrO) glass composition and the resultant mixtures were subsequently reacted with aqueous PAA (50 wt % addition) to produce three GPCs. The incorporation of Ge in the glass phase was found to result in decreased working (142 s to 112 s) and setting (807 s to 448 s) times for the cements manufactured from them, likely due to the increase in crosslink formation between the Ge-containing glasses and the PAA. Compressive (σc) and biaxial flexural (σf) strengths of the cements were examined at 1, 7 and 30 days post mixing and were found to increase with both maturation and Ge content. The bonding strength of a titanium cylinder (Ti) attached to bone by the cements increased from 0.2 MPa, when placed, to 0.6 MPa, after 14 days maturation. The results of this research indicate that Germano-Silicate based GPCs have suitable handling and mechanical properties for cranioplasty fixation.

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The effect of composition and annealing on the properties of aluminum free GPCs: A preliminary evaluation

Cited by 8 publications

References 15 publications

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

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

Incorporating Germanium Oxide into the Glass Phase of Novel Zinc/Magnesium-Based GPCs Designed for Bone Void Filling: Evaluating Their Physical and Mechanical Properties

Glass Polyalkenoate Cements Designed for Cranioplasty Applications: An Evaluation of Their Physical and Mechanical Properties

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