diplomsko delo
Neža Kotnik (Author), Peter Bohinc (Reviewer), Ivan Anžel (Mentor), Franc Rojko (Co-mentor)

Abstract

Uvod: Dentalna keramika že dolgo opravičuje svojo uporabo v dentalni medicini. Da se lahko uporablja na področju laboratorijske zobne protetike, mora poleg varnega in neinvazivnega posega v gostiteljevo telo zagotavljati tudi dobre mehanske lastnosti in visok estetski videz. Takšno keramiko imenujemo biokeramika in v to skupino sodi tudi steklokeramika, ki je danes v dentalni medicini najpogosteje uporabljen keramični material. Tako kot je značilno za vse keramične materiale, velja tudi za biokeramiko, da je krhka, saj se že v elastičnem področju obremenitve na površini pojavijo razpoke. Ta problem se na področju dentalne medicine najpogosteje rešuje z dodatkom kovinskih materialov, oziroma z izdelavo kovinsko-keramičnih konstrukcij, kar pa žal zmanjša željeno estetiko. V moderni fiksni protetiki so se kot odgovor na ta izziv pojavile polne keramične konstrukcije iz aluminijevega (Al2O3) in cirkonijevega (ZrO2) oksida. V primerjavi s kovinsko-keramičnimi strukturami se lahko ta materiala pohvalita z visoko trdnostjo in trdoto, temperaturno stabilnostjo, visoko odpornostjo na agresivno okolje, korozijsko in obrabno odpornostjo, ter boljšo prosojnostjo kot steklo infiltrirana keramika. Tako lahko pacientu zagotovimo material, ki ima dobre mehanske lastnosti in hkrati nudi visok estetski videz. Doseganje optimalnih lastnosti je odvisno od čistosti keramičnega prahu, porazdelitve velikosti prašnih delcev ter od pogojev stiskanja in sintranja. Namen: Namen diplomskega dela je bil analizirati zgradbo in lastnosti ZrO2 in Al2O3 keramike in ugotoviti katera od obeh že predpisanih tehnologij (tehnologija izdelave ZrO2, oziroma tehnologija izdelave Al2O3) zagotavlja konstantnejšo kvaliteto izdelka z manjšim odstopanjem mehanskih lastnosti od predpisanih vrednosti. S tem smo razkrili, kateri material je zanesljivejši in posledično primernejši za izdelavo zobnih nadomestkov. Dodatno je bil namen diplomskega dela izdelati dva nadomestka iz cirkonijeve oksidne keramike. Metode dela: Diplomsko delo je sestavljeno iz teoretičnega in eksperimentalnega dela. V teoretičnem delu je bila z uporabo strokovne literature, ki je bila na voljo na spletnem mestu Google Učenjak ter Medicinski knjižnici Ljubljana, izvedena analiza strukture in lastnosti izbranih materialov. V eksperimentalnem delu smo na osnovi predpisanih tehnologij izdelali preizkušance Al2O3 in ZrO2, ki smo jih nato uporabili za izvedbo mehanskih preizkusov. Vsi preizkušanci so bili testirani pod enakimi pogoji. Rezultati: Preizkušanci so bili pripravljeni v zobnem laboratoriju Dentom v Ljubljani in zobnem laboratoriju Franca Rojka na Ptuju. Izvedba preizkusov pa na Inštitutu za tehnologijo materialov na Fakulteti za strojništvo Univerze v Mariboru. Razprava in zaključek: Na podlagi upogibnih testov s katerimi je bil določen prelomni modul za cirkonijevo in aluminijevo oksidno keramiko, lahko povzamemo, da ima cirkonijeva oksidna keramika višji prelomni modul in višjo lomno žilavost, ter da je posledično ta keramika primernejša za izdelavo večjih protetičnih konstrukcij. Iz dobljenih rezultatov je tudi razvidno, da zagotavlja predpisana tehnologija izdelave cirkonijeve oksidne keramike manjša odstopanja in večjo konstantnost lastnosti. Aluminijev oksid je občutljivejši na laboratorijsko izdelavo in bolj primerjen za manjše protetične nadomestke.

Keywords

diplomska dela;laboratorijska zobna protetika;cirkonijev oksid;aluminijev oksid;trdota;trdnost;mehanske lastnosti;biokompatibilnost;biokeramika;estetika;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL ZF - University College of Health Studies
Publisher: [N. Kotnik]
UDC: 616.31
COBISS: 115247107 Link will open in a new window
Views: 78
Downloads: 42
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Other data

Secondary language: English
Secondary title: Comparison of structure and properties of Al2O3 and ZrO2 ceramics
Secondary abstract: Introduction: Dental ceramics have long justified their use in dentistry. In order to be used in the field of dental technology, it must not only be safe and non-invasive for the host’s body, but also provide good mechanical properties and a high aesthetic appearance. Such ceramics are called bioceramics and include glass-ceramics, which is still the most commonly used material in dentistry today. As is typical for all ceramic materials, bioceramics are brittle, with cracks appearing on the surface of the material already in the elastic range of the load. In the field of dentistry, this problem is most often solved by the addition of metal materials or by the construction of metal-ceramic crowns or bridges, which unfortunately reduces the desired aesthetics. In modern fixed prosthodontics full ceramic frameworks made of aluminium (Al2O3) and zirconium oxide (ZrO2) have emerged as a response to this challenge. Compared to metal-ceramic structures, these materials boast high strength and hardness, temperature stability, high resistance to aggressive environments, corrosion and abrasion resistance, and better translucency than glass-infiltrated ceramics. This allows us to provide the patient with a material that has good mechanical properties and at the same time offers a high aesthetic appearance. For optimum properties to be achieved depends on the purity of the powder, the particle size distribution, and the compression and sintering conditions. Purpose: The aim of this study is to analyse the structure and properties of ZrO2 and Al2O3 ceramics and to determine which of the two already prescribed technologies (ZrO2 and Al2O3) provides a more consistent product quality with a smaller deviation of mechanical properties from the prescribed values. This has revealed which material is more reliable and therefore more suitable for dental crowns. Additionally, the aim of my thesis was to produce two zirconia ceramic substitutes. Methods: The thesis consists of a theoretical and an experimental part. In the theoretical part, an analysis of the structure and properties of the selected materials was performed using the literature available on the Google Scholar website and the Ljubljana Medical Library. In the experimental part, Al2O3 and ZrO2 test specimens were made based on the prescribed technologies and used for mechanical tests. All subjects were tested under the same conditions. Results: The test specimens were prepared in the Dentom dental laboratory in Ljubljana and the Franc Rojko dental laboratory in Ptuj. The tests were made at the Institute of Materials Technology at the Faculty of Mechanical Engineering University of Maribor. Discussion and conclusion: Based on the bending tests, which were used to determine the fracture modulus of zirconia and alumina ceramics, it can be summarised that zirconia ceramics have a higher fracture modulus and higher fracture toughness and as a consequence these ceramics are more suitable for the fabrication of larger dental prosthetics constructions. The results also show that the prescribed zirconia ceramics manufacturing technology ensures lower variation and higher constancy of properties.
Secondary keywords: diploma theses;laboratory dental prosthetics;zirconium oxide;alumina;hardness;strength;mechanical properties;biocompatibility;bioceramics;aesthetics;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Zdravstvena fak., Oddelek za protetiko
Pages: 35 str., [18] str. pril.
ID: 15899356