Logo Logo
Switch Language to German

Ilie, Nicoleta (2021): Frequency-related viscoelastic properties in high translucent CAD-CAM resin-based composites. In: Journal of the Mechanical Behavior of Biomedical Materials, Vol. 118, 104427

Full text not available from 'Open Access LMU'.


Objective: The study aims to quantify the viscoelastic properties of representative dental CAD/CAM resin-based composites (RBC) and to determine the effects of loading frequencies on the viscoelastic material response in comparison to clinically established CAD/CAM glass ceramics. Methods: Eight RBCs, one leucite-reinforced, and one lithium disilicate glass-ceramics were selected. The quasistatic (indentation hardness H-IT, indentation modulus, E-IT) and viscoelastic (storage modulus E', loss modulus E '', loss factor tan delta) material behavior was monitored by a depth-sensing indentation test equipped with a DMA module. A low-magnitude oscillating force was therefore superimposed onto a quasi-static force (F-max = 1000 mN) at 20 different frequencies in the range 1-50 Hz. One and multiple-way analysis of variance (ANOVA), the Tukey honestly significant difference (HSD) post-hoc tests (alpha = 0.05), and a Pearson correlation analysis were used for data analysis. Results: The quasi-static parameters increased with the crystalline phase in glass ceramics and with the amount of inorganic filler in RBCs. The tan delta, which is related to the damping capacity of a material, increased with the increasing amount of glass phase in glass ceramics or with the amount of organic phase in RBCs. A pronounced influence of the frequency on the measured parameters and their patterns of variation was observed. H-IT was up to ten time higher in glass ceramics compared to RBCs and highest at the lowest frequency (1 Hz). Parameters E-IT and E' differ less and were lowest at the lowest frequency. E '' distinguished three different patterns of variation with frequency. The tan S decreased rapidly with frequency in glass ceramics, while the decrease in RBCs was gradually. Frequency influenced stronger tan delta (p < 0.001, eta(2)(P) = 0.85), followed by E' (p < 0.001, eta(2)(P) = 0.773), E-IT (p < 0.001, eta(2)(P) = 0.772), and E '' (p < 0.001, eta(2)(P) = 0.714), and less H-IT (p < 0.001, eta(2)(P) = 0.384). Conclusions: All materials sowed viscoelastic behavior related to their microstructure and the internal friction created by grain or interphase boundary relaxation. RBCs have better damping capabilities over a wider frequency range. The deviations from the ideal elasticity were significantly lower in the glass ceramics than in the RBCs.

Actions (login required)

View Item View Item