Degree of conversion and mechanical properties of a BisGMA:TEGDMA composite as a function of the applied radiant exposure

Calheiros, Fernanda Calabró; Daronch, Márcia; Rueggeberg, Frederick A.; Braga, Roberto Ruggiero

doi:10.1002/jbm.b.30897

Cited by 87 publications

(61 citation statements)

References 93 publications

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“…23 Additionally, other characteristics may also interfere with hardness, including the chemical structure of the monomers and the type and density of the cross-link bonds. 24 This means that the relation between DC and hardness is not always straightforward. 25 Although light-cured resin cements are usually indicated for cementation of thin porcelain and glass-ceramic veneers, as well as inlays and onlays, in the present study, this cement was also evaluated under IC and ZR, for the purpose of comparison with the maximum polymerization achieved by curing without any spacer.…”

Section: Discussionmentioning

confidence: 99%

Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements

et al. 2013

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This study evaluated: I) the effect of photo-activation through ceramics on the degree of conversion (DC) and on the Knoop hardness (KHN) of light-and dual-cured resin cements; and II) two different protocols for obtaining the spectra of uncured materials, to determine the DC of a dual-cured resin cement. Thin films of cements were photoactivated through ceramics [feldspathic porcelain (FP); lithium disilicate glass-ceramics of low translucency (e.max-LT), medium opacity (e.max-MO) and high translucency (e.max-HT); glass-infiltrated alumina composite (IC) and polycrystalline zirconia (ZR)] with thicknesses of 1.5 and 2.0 mm. DC was analyzed by Fourier transform infrared (FTIR) spectroscopy. Two protocols were used to obtain the spectra of the uncured materials: I) base and catalyst pastes were mixed, and II) thin films of base and catalyst pastes were obtained separately, and an average was obtained. KHN assessment was performed with cylindrical specimens. The results were analyzed by ANOVA and Tukey's test (α = 0.05). The light-cured cement showed higher DC (61.9%) than the dual-cured cement (55.7%). The DC varied as follows: FP (65.4%), e.max-HT (65.1%), e.max-LT (61.8%), e.max-MO (60.9%), ZR (54.8%), and IC (44.9%). The light-cured cement showed lower KHN (22.0) than the dual-cured (25.6) cement. The cements cured under 1.5 mm spacers showed higher KHN (26.2) than when polymerized under 2.0 mm ceramics (21.3). Regarding the two protocols, there were significant differences only in three groups. Thus, both methods can be considered appropriate. The physical and mechanical properties of resin cements may be affected by the thickness and microstructure of the ceramic material interposed during photo-activation.

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Section: Discussionmentioning

confidence: 99%

Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements

et al. 2013

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“…In the dry condition, G24 differed significantly from baseline following the same trend as for %DC in which G24 also presented the highest value and significance. Increased %DC is known to improve resin mechanical properties such as surface hardness 20 . In the present study, group G24 indeed exhibited the significantly highest changes in the evaluated properties.…”

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confidence: 99%

Properties of experimental resins based on synthesized propoxylated bis-GMA with different propionaldehyde ratios

et al. 2012

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The effect of different propionaldehyde ratios on the properties of bis-GMA-based comonomers and copolymers diluted with propoxylated bis-GMA (CH 3 bis-GMA) was evaluated. Five experimental comonomers were prepared combining bis-GMA with CH 3 bis-GMA and propionaldehyde at 0, 2, 8, 16, 24 mol%. Light polymerization was effected with the use of 0.2 wt. (%) each of camphorquinone and N,N-dimethyl-p-toluidine. Resin degrees of conversion (%DC) were evaluated by FT-IR spectrophotometry and T g by Differential Scanning Calorimeter. Complex viscosity (η*), the effect of temperature on η*, and Microhardness (H) for dry and wet samples were also determined. Data were analyzed by Student's t-test, one-way ANOVA and Tukey-Kramer test (α = 0.05). The group with 24 mol% additive had a significant increase in %DC and H, and the lowest comonomer T g and η*. No remarkable variation was noted in copolymers T g s. All resins presented Newtonian behavior of viscosity, which linearly decreased with increased temperature. The η* decreased sigmoidally as the additive ratio increased.

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“…A lower hardness value indicates the lower density of polymer structure. 25 There is a correlation between conversion and polymerization rate of a resin material and micro surface hardness of the material during the polymerization, and it gives information about monomer conversion. 26 Also, mixing conditions of adhesive resin cement polymerization and additional materials in an environment have an effect on polymerization reaction.…”

Section: Discussionmentioning

confidence: 99%

The effect of dentin desensitizers on shear bond strengths and vickers surface hardness of self-adhesive resin cement

Alkurt¹,

Duymuş²,

Gündoğdu³

et al. 2018

Yeditepe J Dent

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Degree of conversion and mechanical properties of a BisGMA:TEGDMA composite as a function of the applied radiant exposure

Abstract: DC and mechanical properties increased with radiant exposure. Variables leveled off at high H levels.

Cited by 87 publications

References 93 publications

Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements

Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements

Properties of experimental resins based on synthesized propoxylated bis-GMA with different propionaldehyde ratios

The effect of dentin desensitizers on shear bond strengths and vickers surface hardness of self-adhesive resin cement

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