Effect of cross-linking agents on the molecular properties of denture base resins

Moharram, M. A.; Nour, Kamal N. Abdel; Hakeem, N. A.; Abou-Table, Z. A.; Badr, Nadia

doi:10.1007/bf01133747

Cited by 7 publications

(7 citation statements)

References 6 publications

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“…Vibrational frequencies were computed to verify that the stationary states were optimized to the correct structures and to compute vibrational entropies, zero-point energies, and thermal corrections to enthalpies at 298 K. Solvent effects were described using the universal solvent model with solvent parameters for ethyl acetate (EtOAc) because of its structural similarity to (meth)acrylate monomers . Furthermore, the dielectric constant of EtOAc of ∼6 is suitable for describing the dielectric environment produced by common bulk (meth)acrylate monomers with dielectric constants ranging from 2.5 to 11. , Gibbs free energies were corrected using bulk-resin environment simulation, according to a previous ref . The monomer used in the computational investigation of the monomer addition kinetics was ethyl methacrylate.…”

Section: Methodsmentioning

confidence: 99%

“…29 Furthermore, the dielectric constant of EtOAc 25 of ∼6 is suitable for describing the dielectric environment produced by common bulk (meth)acrylate monomers with dielectric constants ranging from 2.5 to 11. 30,31 Gibbs free energies were corrected using bulk-resin environment simulation, according to a previous ref 29. The monomer used in the computational investigation of the monomer addition kinetics was ethyl methacrylate.…”

Section: ■ Computational Methodsmentioning

confidence: 99%

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High-Efficiency Radical Photopolymerization Enhanced by Autonomous Dark Cure

et al. 2020

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Radical photopolymerization (RPP) has grown into a multibillion-dollar technology for reduced energy consumption and waste with increased productivity. However, radical-mediated polymerization ceases almost immediately following discontinuation of irradiation because of rapid termination of reactive centers. This restricts the wider use of RPP in applications that involve light attenuation or irregular surfaces because uniform polymerization is not guaranteed for these challenging exposure conditions and the resultant undercuring leads to compromised material properties and harmful leachable monomers. Herein, we developed a unique radical dark-curing photoinitiator (DCPI) that continues its polymerization beyond the cessation of irradiation. The DCPI achieved a remarkable 25–60% additional conversion over a 1 h period, when light was shuttered at 20% conversion, compared to the 1–3% additional conversion achieved by a Norrish type II control photoinitiator. We elucidated the origin of the high photon efficiency using computational studies and experiments, which suggest that the DCPI may be the most-photon-efficient photoinitiator to date. We also demonstrated that the mechanical properties of dark-cured polymer are similar to and even exceed those of the corresponding polymer obtained by extended photocuring. In particular, the initial 0.1 MPa storage modulus continuously developed to 4.3 MPa without further irradiation, while also exhibiting ∼30% less shrinkage stress than the full exposure control. With its superior photo- and dark-polymerization efficiency, the DCPI enhances the performance of many existing RPP processes while extending RPP to heretofore unattainable applications. The DCPI accomplishes such a performance through an inherent automatic rectification of initially undercured regions and defies the RPP paradigm that light dosage directly correlates to conversion.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Computational Methodsmentioning

confidence: 99%

High-Efficiency Radical Photopolymerization Enhanced by Autonomous Dark Cure

et al. 2020

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“…The M06 functional was selected based on prior benchmarking that demonstrated its favorable performance when applied to ground-state and excited-state systems involving organic and organometallic molecules. , Vibrational frequencies were calculated to verify that the stationary-state geometries were optimized to the correct structures and to compute vibrational entropies, zero-point energies, and thermal corrections at 298 K. Solvent effects were described using the universal solvation model (SMD) with parameters describing ethyl acetate (EtOAc) because of its structural similarity to (meth)acrylate monomers. Furthermore, the EtOAc’s dielectric constant of ∼6 is suitable for representing the dielectric environment produced by common bulk (meth)acrylate monomers with dielectric constants ranging from 2.5 to 11. , Electronic structure calculations for excited states, including UV–vis spectra, were executed via time-dependent DFT (TD-DFT) at the same M06/6-31+G(d,p)/SMD-EtOAc level of theory.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, the EtOAc's dielectric constant 68 of ∼6 is suitable for representing the dielectric environment produced by common bulk (meth)acrylate monomers with dielectric constants ranging from 2.5 to 11. 73,74 Electronic structure calculations for excited states, including UV−vis spectra, were executed via time-dependent DFT (TD-DFT) at the same M06/6-31+G(d,p)/SMD-EtOAc level of theory. ■ RESULTS AND DISCUSSION Photopolymerization Kinetics.…”

Section: ■ Introductionmentioning

confidence: 99%

Independent Control of Singlet Oxygen and Radical Generation via Irradiation of a Two-Color Photosensitive Molecule

et al. 2019

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Free-radical polymerizations are used for a wide range of applications but are detrimentally impacted by the presence of oxygen. Zinc phthalocyanines have been previously used as singlet oxygen generators to excite radical-consuming ground-state triplet oxygen into its less reactive singlet state prior to photoexcitation of a photoinitiator. We report for the first time that polymerization can be achieved via irradiation of UV band of phthalocyanine and that photosensitization and photoinitiation can be independently achieved via irradiation of its two distinct absorption bands to reduce oxygen inhibition and initiate polymerization without the need for additional treatment. We propose a mechanism for this unique photoinitiation phenomenon and verify its feasibility via computational and experimental approaches. This new class of dual-photosensitive molecules shows promising utility in applications that are adversely impacted by the presence of oxygen, such as coatings and stereolithography.

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“…Therefore, once T g is reached, further conversion of MMA does not happen, thereby limiting the conversion of residual monomer with no effect of heat thereafter. Moharram et al 29 concluded that the addition of 12% or 17% of triethylene glycol dimethacrylate (TEGDMA) or tetra hydro furfuryl methacrylate (THFMA) cross-linkers to the denture base resins reduced the amount of residual monomer. Viljanen et al [30][31][32] concluded that addition of dendritic cross-linker (dendrimer) to denture base resin resulted not only better mechanical properties but also a high degree of polymerization and low residual monomer.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of In Vitro Cytotoxicity of Heat-cure Denture Base Resin Processed with a Dual-reactive Cycloaliphatic Monomer

Karthigeyan¹,

Sreevarun²,

Balu³

et al. 2019

The Journal of Contemporary Dental Practice

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Aim:The aim of this study is to evaluate cytotoxicity of tricyclodecane dimethanol diacrylate (TCDDMDA) when added to conventional heatcure methyl methacrylate (MMA) monomer at 10% and 20% (v/v) concentrations. Materials and methods: Twenty seven disk-shaped processed specimens were divided into control group (n = 9; comprises specimens made without substituting TCDDMDA in MMA) and two experimental groups (n = 9 each; specimens prepared by substituting TCDDMDA in MMA at 10% and 20% (v/v) concentration). Eluates were prepared by placing three specimens of each group into 9 mL of culture medium and then incubated at 37ºC for 24 hours. Continuous cells lines of L929 mouse fibroblast cells were used and MTT assay was employed to assess cytotoxicity. One-way analysis of variance (ANOVA) with post hoc Tukey's honestly significant difference (HSD) test was used to compare the mean optical density (OD) values and cell viability among the groups. Results: A statistically significant difference was obtained (p = 0.000) when the mean and standard deviation of OD and cell viability (%) of the groups were compared. Highest OD value and cell viability was obtained with E20 group followed by E10 group. Conclusion: Addition of TCDDMDA in MMA of heat-cure denture base resin has no cytotoxic effect on L929 mouse fibroblasts. Clinical significance: Dual-reactive TCDDMDA is a crosslinking monomer which has no cytotoxic effects on mammalian cell cultures. Hence, incorporation of TCDDMDA to MMA can be extrapolated and projected for fabricating dentures without compromising biocompatibility.

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Effect of cross-linking agents on the molecular properties of denture base resins

Cited by 7 publications

References 6 publications

High-Efficiency Radical Photopolymerization Enhanced by Autonomous Dark Cure

High-Efficiency Radical Photopolymerization Enhanced by Autonomous Dark Cure

Independent Control of Singlet Oxygen and Radical Generation via Irradiation of a Two-Color Photosensitive Molecule

Evaluation of In Vitro Cytotoxicity of Heat-cure Denture Base Resin Processed with a Dual-reactive Cycloaliphatic Monomer

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