Naslov (srp)

Uticaj tehnološkog procesa proizvodnje na biofunkcionalne osobine nikl-titanijum legure za primenu u stomatološkoj protetici : doktorska disertacija

Autor

Miličić-Lazić, Minja, 1988-

Doprinosi

Grgur, Branimir N., 1965-
Đorđević, Igor, 1972-
Radović, Katarina, 1974-
Lazić, Vojkan, 1963-
Rudolf, Rebeka, 1969-

Opis (srp)

Nikl-titanijum legure predstavljaju napredne funkcionalne materijale koji mogu pokazati različitemehaničke, hemijske i biofunkcionalne osobine zavisno od procesa proizvodnje. U ovoj doktorskojdisertaciji primenjena je metoda kontinualnog livenja za dobijanje nikl-titanijum legure i sprovedene sumetode za ispitivanje biofunkcionalnih osobina dobijenih odlivaka. Osobine dobijene legure poređenesu sa komercijalno dostupnom nikl-titanijum legurom dobijenom klasičnim postupkom livenja,odnosno pretapanjem u vakuum peći sa elektrootpornim zagrevanjem i finalnim livenjem u različiteingote.Hemijska karakterizacija uzoraka vršena je metodama semikvantitativne i kvalitativne analizeskenirajućom elektronskom mikroskopijom obogaćenom energijsko–disperzivnom rendgenskomspektroskopijom (SEM–EDX), rendgenskom fluorescentnom spektoskopijom (XRF) i difrakcijompovratnog raspršenja elektrona (EBSD). U okviru analize mehaničkih osobina legura, tvrdoća površineuzoraka ispitivana je statičkom metodom po Vikersu. Koroziono ponašanje kontinualno i klasičnolivene legure analizirano je kroz standardizacijom regulisanu grupu testova za ispitivanje korozijedentalnih legura (ISO 10271-2011). Postojanost uzoraka u pH neutralnoj i kiseloj sredini ispitivana jestatičkim testom uranjanja i naknadnom analizom migracije jona u medijum metodom induktivnospregnute plazme (ICP). Sklonost legura ka tamnjenju ispitana je testom sulfidne matrice, nakon čegaje vršeno elektrohemijsko ispitivanje metodom potenciodinamičke polarizacije. Da bi se ispitao udeoodređenih hemijskih elemenata novoformiranog površinskog sloja nakon testova korozije vršeno jeispitivanje topografije i sastava površine uzoraka fokusiranim jonskim snopom elektronskemikroskopije.U cilju ispitivanja citotoksičnih svojstava nikl-titanijum legure dobijene metodom klasičnog ikontinualnog livenja sproveden je MTT test ćelijske vijabilnosti kroz dve vrste kontakta materijala ićelija fibroblasta humanog porekla. Pri direktnom kontaktu analizirana je toksičnost same površinematerijala, dok je indirektni kontakt podrazumevao analizu toksičnog efekta molekula materijalaotpuštenih u medijum za ćelijsku kulturu.Dobijeni rezultati pokazali su da su najvažnije prednosti kontinualnog nad klasičnim livenjem:mogućnost dobijanja odlivaka malih dimenzija, što eliminiše potrebu za daljim postupcima hladne ilitople obrade, stabilnija mikrostruktura i bolja koroziona postojanost legure u kiseloj sredini...

Opis (srp)

Stomatološke nauke - Stomatološka protetika / Dental Sciences- Dental Prosthodontics Datum odbrane: 28.11.2023.

Opis (eng)

Nickel-titanium alloys represent smart, functional materials that can exert different mechanical,chemical, and biofunctional properties depending on the manufacturing process. In this doctoraldissertation, nickel-titanium alloy was produced by the continuous casting method (NiTi-2).Biofunctional properties of continuous cast alloy were compared with commercial nitinol (NiTi-1)manufactured by the classical process, i.e., from remelting in a vacuum furnace with electro-resistiveheating and final casting into ingots.The chemical composition of the samples was analyzed via semiquantitative and qualitative analysismethods using scanning electron microscopy enriched with energy-dispersive X-ray spectroscopy(SEM-EDX), X-ray fluorescence spectroscopy (XRF), and electron backscatter diffraction (EBSD). Inorder to evaluate the mechanical properties of tested samples, the hardness was measured using thestatic Vickers test. The corrosion behavior of continuous and conventional cast alloys was evaluatedaccording to the standard for corrosion testing of dental alloys (ISO 10271-2011). The release of metalions in pH neutral and acidic solutions was measured by static immersion test. The chemical content ofthe suspensions was overseen by the inductively coupled plasma (ICP) method. The surfacediscoloration of the tested alloys was evaluated using a sulfide tarnish test. Corrosion potentials wereinvestigated using polarization measurements. Finally, the formed corrosion layers on all samples werecharacterized with the focused ion beam (FIB) technique.An MTT assay was performed to evaluate the biocompatibility testing of the NiTi-1 and NiTi-2samples. During direct exposure, the toxicity of the sample's surface was examined, while indirectcontact included the cell's contact with ion-enriched supernatants.The results of our research showed that the most important advantages of continuous casting overclassical casting are: the ability to produce strands of small diameter, which eliminates the need forfurther cold or hot processing procedures, a more stable microstructure, and better corrosion resistancein an acidic solution. Increased mitochondrial activity of cells grown directly on the tested samples wasrecorded, showing that contact with the oxide layer on the surface of the samples leads to increasedmitochondrial activity and, thus, cell proliferation. Over time, in the indirect test, a slight decrease incell viability was observed, but the number of viable cells did not indicate subtoxic doses of moleculesreleased into the cell culture medium. During both types of cell contact with the investigated alloys,their satisfactory biocompatibility was demonstrated...

Jezik

srpski

Datum

2023

Licenca

Ovo delo je licencirano pod uslovima licence
Creative Commons CC BY-NC-ND 3.0 AT - Creative Commons Autorstvo - Nekomercijalno - Bez prerada 3.0 Austria License.

http://creativecommons.org/licenses/by-nc-nd/3.0/at/legalcode

Predmet

OSNO - Opšta sistematizacija naučnih oblasti, Stomatologija

Nickel-titanium, continuous casting, characterization, biofunctional properties, corrosion, biocompatibility

OSNO - Opšta sistematizacija naučnih oblasti, Stomatologija

nikl-titanijum; kontinualno livenje; karakterizacija; biofunkcionalne osobine; korozija; biokompatibilnost

616.314-77(043.3)