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Surface free energy and roughness of flowable dental composites

Łagan Sylwia, Chojnacka-Brożek Agnieszka, Liber-Kneć Aneta, Malik Gabriela

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 3

EN

The surface properties like roughness, wettability and surface free energy are important for utility properties of traditional and flowable dental restorative composites, due to their role in plaque formation, discoloration, mechanical wear or adhesion and bonding. The goal of our work was to assess the surface free energy (SFE) and the surface roughness (Ra) of three commercial flowable dental composites: everX Flow (bulk), everX Flow (dentin) and Flow-Art. Methods: Surface roughness, contact angle and surface free energy were determined for tested composites. Two surface states (control and roughened) were compared. Roughness was measured with the use of the 3D optical profilometer. The contact angle (CA) was determined through the sessile drop method with the use of four different probing liquids. This enabled to apply two surface free energy approaches (Owens–Wendt (O-W) and van Oss– Chaudhury–Good (LWAB)). Additionally, Zisman’s approach (γC) was used. Results: The water contact angle values were similar for Flow-Art (67.56±1.49°) and everX Flow (bulk) (68.94±2.72°) compared to higher value for everX Flow (dentin) (74.39±2.05°). SFE was in the range from 43 to 50 mJ/m2 for O-W and from to 62 mJ/m2 for LWAB. The γC was from 37 47 to 45 mJ/m2 . Conclusions: Roughening composites’ surface influenced on increasing the CA value. All approaches of surface free energy calculations provide useful data for predicting interactions between flowable composites and dental tissues. Tested composites showed good wetting for initial state of surface after polymerization. These influence on better adhesion of the material to the bonding system during dental restoration.

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Stress relaxation of porcine tendon under simulated biological environment: experiment and modeling

Łagan Sylwia D., Liber-Kneć Aneta

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 1

59--68

EN

Purpose: The aim of the study was to investigate the viscoelastic response in the low and high physiological strain with the use of experimental and modeling approach. Methods: Viscoelastic response in the low, transition and high physiologic strain (3, 6 and 9%) with consideration of simulated biological environment (0.9% saline solution, 37 °C) was measured in relaxation tests. Preconditioning of tendons was considered in the testing protocol and the applied range of load was obtained from tensile testing. The quasi-linear viscoelasticity theory was used to fit experimental data to obtain constants (moduli and times of relaxation), which can be used for description of the viscoelastic behavior of tendons. The exponential non-linear elastic representation of the stress response in ramp strain was also estimated. Results: Differences between stress relaxation process can be seen between tendons stretched to the physiological strain range (3%) and exceeding this range (6 and 9%). The strains of 6% and 9% showed a similar stress relaxation trend displaying relatively rapid relaxation for the first 70 seconds, whereas the lowest strain of 3% displayed relatively slow relaxation. Conclusions: Results of the model fitting showed that the quasi-linear viscoelastic model gives the best fit in the range of low physiological strain level.

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Polymerization shrinkage and compressive strength of microhybrid dental composite

Liber-Kneć Aneta, Łagan Sylwia

Engineering of Biomaterials

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2019

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Vol. 22, no. 153 spec. iss.

22

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Mechanical and absorption properties of commercial hydrogel dressings

Łagan Sylwia, Liber-Kneć Aneta

Engineering of Biomaterials

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2019

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Vol. 22, no. 153 spec. iss.

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