Untitled

Abstract

Four long-chain aliphatic organic diluents, triethylene glycol dimethacrylate (TEGDMA), ethylene glycol dimethacrylate (EDMA), triethyleneglycol diacrylate (TEGDA) and tetraethylene glycol diacrylate (TTEGDA) were used as diluents for preparing a visible-light-cured dental composite. Cured samples of pastes prepared using the above diluents were stored separately for a period of 60 days in distilled water at 37 degrees C and tested for changes in compressive strength, diametral tensile strength and microhardness at specific intervals of 1, 7, 14, 21, 28 and 60 days. Samples prepared using TEGDMA showed better strength values initially compared with the composite specimens prepared using the rest of the diluents although they are found to deteriorate slowly upon storage in distilled water up to 60 days. Samples prepared using EDMA showed retention in properties whereas samples prepared using TEGDA and TTEGDA showed large deviations in strength values during the first 28 days, did not deteriorate further and were found either to show improvement upon ageing or to remain constant. Sorption values seem to reach a maximum for all composites and then to decrease further after 14 days whereas solubility is found to increase with time.

Molecular Dynamics of Ethylene Glycol Dimethacrylate Glass Former: Influence of Different Crystallization Pathways

“…The chemical and physical properties exhibited by fully amorphous, partial and wholly crystalline forms of the same substance, are significantly different, whose knowledge is also important for medical purposes. In the present work, ethylene glycol dimethacrylate (EGDMA), used as a cross-linking agent in dental restorative composites , and ophthalmic applications, , is used to explore the different aspects concerning molecular mobility and relationship between thermal treatment and transformation pathways since it is able to both vitrify and crystallize. Indeed, EGDMA belongs to the n -ethylene glycol dimethacrylate family that easily circumvents crystallization entering in the supercooled regime and vitrifying upon further cooling.…”

Influence of the base and diluent methacrylate monomers on the polymerization stress and its determinants

“…Due to its high viscosity at room temperature (∼ 1200 Pa s),7 BisGMA is usually combined with diluent monomers (with lower viscosity and generally lower molecular weight) to allow not only for inorganic filler incorporation (that ensure adequate mechanical properties) but also to improve medium mobility during the polymerization reaction, ultimately increasing conversion 8. The higher conversion, allied to the augmented reactive group concentration, leads to increased volumetric shrinkage9, 10 (which is clearly a disadvantage), but also contributes to denser, more crosslinked networks, less prone to degradation 11, 12. This is even more evident for diluent monomers with functionalities greater than two 13, 14…”

“…In turn, the use of larger molecules such as TETGDMA, D 3 MA (1,10‐decanediol dimethacrylate; M w = 310 g/mol) and TMPTMA (trimethylol propane trimethacrylate; M w = 338 g/mol) would afford lower volumetric shrinkage. Due to its flexibility, D 3 MA renders a polymer with low elastic modulus,12, 15 also contributing less stress. Obviously, reductions in stress due to lower shrinkage or lower modulus should not come at the expense of conversion, or long term longevity of restorations will likely be reduced.…”

Multifractality in the copolymerization of Bis‐GMA/TEGDMA by pulsed photoacoustics

“…However, Bis‐GMA handling during dental restorations is troublesome because of its high viscosity 1. To increase fluidity and to enhance the formation of a three‐dimensional molecular network (by crosslinking) triethylene‐glycol‐dimethacrylate (TEGDMA) is usually mixed with Bis‐GMA 2, 3. The photopolymerization reaction involves conversion of the double bonds of the methacrylate groups of both, Bis‐GMA and TEGDMA, by a free radical mechanism.…”