20.500.12556/DKUM-92242 Experimental investigation of the biofunctional properties of nickel–titanium alloys depending on the type of production Nickel–titanium alloys used in dentistry have a variety of mechanical, chemical, and biofunctional properties that are dependent on the manufacturing process. The aim of this study was to compare the mechanical and biofunctional performances of a nickel–titanium alloy produced by the continuous casting method (NiTi-2) with commercial nitinol (NiTi-1) manufactured by the classical process, i.e., from remelting in a vacuum furnace with electro-resistive heating and final casting into ingots. The chemical composition of the tested samples was analyzed using an energy dispersive X-ray analysis (EDX) and X-ray fluorescence (XRF). Electron backscatter diffraction (EBSD) quantitative microstructural analysis was performed to determine phase distribution in the samples. As part of the mechanical properties, the hardness on the surface of samples was measured with the static Vickers method. The release of metal ions (Ni, Ti) in artificial saliva (pH 6.5) and lactic acid (pH 2.3) was measured using a static immersion test. Finally, the resulting corrosion layer was revealed by means of a scanning electron microscope (SEM), which allows the detection and direct measurement of the formatted oxide layer thickness. To assess the biocompatibility of the tested nickel–titanium alloy samples, an MTT test of fibroblast cellular proliferation on direct contact with the samples was performed. The obtained data were analyzed with the IBM SPSS Statistics v22 software. EDX and XRF analyses showed a higher presence of Ni in the NiTi-2 sample. The EBSD analysis detected an additional NiTi2 -cubic phase in the NiTi-2 microstructure. Additionally, in the NiTi-2 higher hardness was measured. An immersion test performed in artificial saliva after 7 days did not induce significant ion release in either group of samples (NiTi-1 and NiTi-2). The acidic environment significantly increased the release of toxic ions in both types of samples. However, Ni ion release was two times lower, and Ti ion release was three times lower from NiTi-2 than from NiTi-1. Comparison of the cells’ mitochondrial activity between the NiTi-1 and NiTi-2 groups did not show a statistically significant difference. In conclusion, we obtained an alloy of small diameter with an appropriate microstructure and better response compared to classic NiTi material. Thus, it appears from the present study that the continuous cast technology offers new possibilities for the production of NiTi material for usage in dentistry. nickel–titanium continuous casting characterization biofunctional properties biocompatibility nikelj-titan kontinuirano litje karakterizacija biofunkcionalne lastnosti biokompatibilnost true false true MDPI AG Angleški jezik Slovenski jezik https://www.mdpi.com/journal/molecules © 2022 by the authors. Članek v reviji 2025-03-24 13:01:06 2025-03-24 13:01:06 2025-03-25 03:09:42 0000-00-00 00:00:00 2022 0 0 14 str. iss. 6 (1960) Vol. 27 March 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2022-01-29 2022-03-15 2022-03-17 621.74:620.1 102129923 10.3390/molecules27061960 1420-3049 molecules-27-01960-v2.pdf molecules-27-01960-v2.pdf 1 01451FDA25786C7E093F82B244B16638 ef4e5dabbe8925826a454d637b126160edddf4fc189cab3b58eb99910f03a92d 11b4efcc-08a8-11f0-b559-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=189610 https://www.mdpi.com/1420-3049/27/6/1960 0 17c816ea-08a8-11f0-b559-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=189611 Fakulteta za strojništvo 0 0 0