Dissertation > Medicine, health > Oral Sciences > Oral orthotics > Dental Materials Science

Study on the Preparation and Properties of Dental Zirconia Nano-ceramic Composites

Author SongWenZhi
Tutor SunHongChen;YangHaiBin
School Jilin University
Course Clinical Stomatology
Keywords Dental ceramic Zirconia Alumina Nanopowder Precipitation Ultrasonic wave Nanocomposites Mechanical properties Spark Plasma Sintering
CLC R783.1
Type PhD thesis
Year 2004
Downloads 839
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Ceramic materials because of their excellent performance as the \material of choice. Since the sixties of last century porcelain matching people to solve the problem, reinforced with metal copings dental porcelain fused to metal (PFM) to become the most commonly used oral fixed prosthesis clinical way, but the presence of the metal underlying metal porcelain teeth there are difficult to overcome the shortcomings, such as: precipitation of metal ions are potentially allergenic, precipitation of metal ions can cause gingival gray line affects the appearance, the presence of opaque layer prevents light through the lack of natural tooth vitality artificial teeth and so on. Therefore, high-strength ceramic materials can be replaced by the underlying metal crown, in order to achieve the best aesthetic effect and biocompatibility of all-ceramic restorations have become a research hotspot in recent years and the development direction of prosthodontics, and have appeared in IPS Impress Hot casting ceramics, In-Ceram infiltration alumina ceramic slip casting series such as all-ceramic materials, in recent years, and with advanced computer-aided design / computer-aided manufacture (CAD / CAM) technology combined developed machinable In-Ceram and Procera porcelain porous aluminum All Ceram alumina ceramic preformed ceramic blocks, which greatly promoted the all-ceramic restorations in clinical applications. However, most of the ceramic material is an ionic bond and covalent bond, and a significant bond with strong directivity, room temperature, or practically no slip dislocation movement, this brittle nature of the ceramic material limits the practical application, to overcome its brittleness, improve the toughness of the material scientists have been trying to solve the problem. lt; WP = 93 gt; methods of traditional ceramic toughening phase transformation toughening, fiber reinforced, toughened whiskers and particles, etc., which is one of the most compelling material phase transformation toughening of zirconia ceramics, due under stress induced tetragonal to monoclinic martensitic transformation and it greatly improved fracture toughness and become the best at room temperature toughness of ceramic materials, it is \The second phase particles fill added to play other ceramic matrix phase transformation toughening effect. In recent years, zirconia ceramic excellent mechanical properties also attracted the attention of oral medical scientists, a compelling new dental materials. In addition to traditional methods toughened in recent years, the development of nanotechnology to make new materials, new technologies are emerging, nano-ceramic is considered to be a strategic way to solve brittle ceramics. Current nano-zirconia ceramics and nano zirconia composite materials has become a hot academic research, so this study intends to nanomaterials technology combined with dental materials research and advanced spark plasma sintering (SPS) introduced dental materials research, in order to developed a high strength, high toughness, can meet the needs of dental restorative materials nano-zirconia composite ceramics, and to explore its enhanced complement tough mechanism for the application of new technologies and new methods to the development of new dental ceramic materials useful exploration. In this study, the specific contents include: (1) the role of ultrasound coprecipitation nanometer ZrO2 (3Y) powders were prepared particle size distribution, good performance sintered nanoparticles was better mechanical properties of ceramic materials premise, the present study easy to operate using the easy control of the reaction conditions, and coprecipitation to zirconium oxychloride, yttrium nitrate as raw materials, nano reverse titration yttrium stabilized zirconia powder to prevent agglomeration occurs during the reaction, a low surface tension used in this experiment The ethanol as reaction solvent, respectively, in the low frequency ultrasonic wave and the reaction is carried out without ultrasound, was observed by TEM, prepared under ultrasound precursor dispersion prepared under non ultrasonic precursor of a better description of the ultrasonic frequency anti-agglomeration. Ultrasonic precursor prepared obtained after calcination at 600 ℃ small particle size dispersed nano ZrO2 (3Y) powder by X-ray diffraction analysis is mainly tetragonal zirconia, and calculated by the average grain size of Scherrer for the D101 = 15.58nm. lt; WP = 94 gt; (2) the role of ultrasound chemical precipitation method to prepare nano (-Al2O3 powder as the raw material of aluminum nitrate and ethanol as the reaction solvent, under the action of low-frequency ultrasound Nano (-Al2O3 powder has been tested, The 1200 ℃ calcined precursor, the resulting dispersion is preferably spherical nano (-Al2O3 powder, the average grain diameter of D202 = 31.44nm. (3) nano-zirconia composite ceramics fill plus different ratios ① Nano zirconia ceramic nanocomposite powder in a volume ratio of 3%, 5%, 10%, 15%, 20%, 30% of the nano-ZrO2 (3Y) powder were added granulated micron zirconia powder, milling mix, 250Mpa dry pressing, the sintered samples were linear shrinkage, density, apparent porosity, mechanical properties and structure analysis by XRD and SEM observation, the results show that adding 3%, 5%, 10% ZrO2 (3Y) nano-powder group flexural strength and fracture toughness values ??with the control group (pure granulated powder ceramic) were statistically significant compared, which added 10% nanopowder best mechanical properties of the ceramic samples, the three bending and fracture toughness values ??were 673.17 ± 47.19Mpa and 9.01 ± 0.82Mpa · m1 / 2; meet the requirements of dental restorative materials; nano powder more than 20%, but decreased mechanical properties, nano powder up to 30%, the test Mechanical properties of samples has been significantly lower than the control group. ② fill plus different proportions nm (-Al2O3 nano powders Al2O3/ZrO2 (3Y) ceramic composite in a volume ratio was 3%, 5%, 10%, 15%, 20% 30% nano (- Al2O3 powder granulation join micron zirconia powder, ball mix, 250Mpa dry pressing, sintering samples in each group after the performance test results showed that the addition of 3%, 5% (- Al2O3 nanopowder group flexural strength and fracture toughness values ??compared with the control group was statistically significant, which added 5% nanopowder best mechanical properties of the ceramic samples, the three-point bending and fracture toughness values ??were 659.17 ± 46.54 Mpa and 8.55 ± 0.89 Mpa · m1 / 2, to meet the requirements of dental materials; nano powder more than 20%, but decreased mechanical properties of the sample. lt; WP = 95 gt; (4) Spark Plasma Sintering dental nano ZrO2 ceramics and nano Al2O3 - ZrO2 (3Y) composite ceramics Preliminary pure ZrO2 Nanoparticles respectively to 50% and the proportion of mixing of nano-Al2O3 - ZrO2 (3Y) composite powders, the application of advanced technology rapid sintering SPS obtained pure nano- ZrO2 ceramic sample cracking, X-ray diffraction analysis showed that the sample base for the m - ZrO2, Y2O3 described wherein the stabilizer is mold carbon reduction rather useless; nano-Al2O3 - ZrO2 (3Y) composite ceramic specimen uncracked

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