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Namen diplomske naloge je bila karakterizacija mikrostrukture ter mehanskih in toplotnih lastnosti dentalnega kompozitnega materiala za zalivke, saj so to ene od najpomembnejših lastnost, ki jih morajo imeti materiali za ta namen. Diplomsko delo je sestavljeno iz teoretičnega in eksperimentalnega dela. V teoretičnem delu so opisi dentalnih materialov, predstavitev kompozitov v dentalni medicini ter vse splošne lastnosti kompozitov. Opredeljen je tudi pomen kompozitov v dentalni medicini in njihov nadaljnji razvoj. V eksperimentalnem delu smo izdelali valje oziroma diske iz kompozita, ki se uporablja za zalivke, in sicer na dva načina, s polimerizacijo po plasteh in polimerizacijo površine celotnega volumna testnega valja. Izmerili smo tlačno trdnost ter ugotovili, da ima kompozit, izdelan po plasteh, višjo tlačno trdnost. Najverjetneje je to zaradi bolj kvalitetne izdelave vzorca v primerjavi z vzorcem, izdelanim s polimerizacijo površine celotnega volumna testnega valja, kjer je popolna polimerizacija potekala samo v površinskih plasteh, v jedru pa najverjetneje ni prišlo do popolne polimerizacije. Kompozitnim vzorcem smo izmerili tudi trdoto in toplotno prevodnost. Trdota po Vickersu je znašala 120 HV, toplotna prevodnost pa 0,5168 W/mK. Z vrstičnim elektronskim mikroskopom (SEM), opremljenim z detektorjem EDXS, smo analizirali površino vzorca izdelanega s polimerizacijo po plasteh in vzorca, kjer smo polimerizirali površino celotnega volumna testnega valja. Ugotovil smo, da ima vzorec, izdelan po plasteh, na površini razpoke. Opravili smo tudi mikrostrukturno analizo ter določili mikrostrukturne sestavine. Ugotovljeno je bilo, da je kompozit pretežno sestavljen iz delcev stekla iz BaO, SiO2 in Al2O3. Vmes pa najdemo tudi delce itrebijevega trifluorida. Matico iz organskega materiala pa z EDXS ni mogoče analizirati. Na osnovi opravljenih preiskav smo ugotovili, da imajo kompozitne zalivke ustrezne fizikalne in mehanske lastnosti za nadomestitev trdih zobnih tkiv, ki pa so pogojene s tehniko in kakovostjo izdelave. Kompozitne zalivke morajo biti izdelane natančno, v absolutni osušitvi – to je v odsotnosti tekočin (npr. vode, sline, krvi), in ob doslednem upoštevanju tehnike za izdelavo kompozitnih zalivk. Le tako bo zagotovljeno ustrezno tesnjenje kompozitne zalivke, in onemogočen nastanek nepravilnosti kot so spremembe v zgradbi materiala in nastanek razpok v materialu. The purpose of diploma work was the characterisation of the microstructure, mechanical properties and thermal characteristics of the dental composite for fillings since these are the most important features of the materials for this purpose. The diploma work consists of theoretical and experimental work. In the theoretical part dental materials, mostly composite materials and their properties are described. The importance of the composites in dental medicine is also defined, as well as their further development. The testing samples in the shape of cylinder made of dental composite were prepared by two different routes which are explained in the experimental, i.e. by polymerisation of single layers from which the sample is composed and by polymerisation of the surface across the whole volume of the sample. It was found that the composite produced by layers had higher compressive strength. This is probably due to a better quality of the sample made by polymerisation of the single layers in comparison to the sample made by polymerisation of the surface across the whole sample. Hardness and thermal conductivity were also measured. The Vickers hardness was 120 HV and thermal conductivity was 0,5168 W/mK. The surface of both samples was analysed with scanning electron microscope (SEM) with attached EDXS detector. Sample which was made by polymerisation of the surface across the sample showed not only porosity but also cracks on the surface. The microstructure analysis of the composite materials was performed and microstructure constituents were determined. It was found that the composite is mainly consisted of glass particles made of BaO, SiO2 and Al2O3. However, some particles of ytterbium trifluoride were also observed. The matrix made of organic materials cannot be analysed with EDXS analysis. Based on performed tests, it was found that the composite fillings have appropriate physical and mechanical properties for the substitution of the solid tooth tissues however, the properties strongly depend on the quality of the production. The composite filling must be made precisely in absolute dry conditions, i.e. in the absence of any liquids (e.g. water, saliva, blood) and with strict consideration and following of the procedures for making composite fillings. Only in this way the appropriate sealing of the composite filling will be ensured and the irregularities such as changes in the material structure and the formation of cracks will be avoided. |
