Polymerization shrinkage of resin mixtures used in dental composites
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Lublin University of Technology, Faculty of Mechanical Engineering, Nadbystrzycka 36, 20-618 Lublin, Poland
Arkona Laboratory of Dental Pharmacology, Nasutów 99C, 21-025 Niemce, Poland
Krzysztof Pałka
Engineering of Biomaterials 2020;(154):16–21
Polymerization of dental composites generates shrinkage in the matrix resulting in numerous clinical problems. The influence of the most commonly used resins on the shrinkage process has not been thoroughly examined so far in the literature. The purpose of this work is to determine the effect of the resin mixture compositions on the volumetric polymerization shrinkage. The mixtures used in the tests were prepared in specific weight proportions to determine the influence of particular monomers, such as Bis-GMA, Bis-EMA, UDMA, and TEGDMA. The shrinkage measurements were performed using the self-designed video-imaging device. The studies showed that the shrinkage decreased in opposite to the Bis-GMA concentration in the mixture with the simultaneous decrease in the Bis-EMA content. The shrinkage value decreased in opposite to the molecular weight only for some monomers and compositions. Bis-EMA resin as a flexible monomer achieved the lower shrinkage values than UDMA, and the highest shrinkage values, above 6%, were achieved by compositions with the 14wt% content of Bis-GMA. Regarding the shrinkage, the most optimal composition was 56wt% Bis-GMA with the addition of Bis-EMA (24wt%) and TEGDMA (20wt%). The obtained shrinkage value was 4.73%.