Decreasing in sintering temperature and improvement in abrasion properties of dental porcelains

降低烧结温度并改善牙瓷的耐磨性能

基本信息

批准号：
10671852
负责人：
BAN Seiji
金额：
$ 2.05万
依托单位：
Aichi-Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671852/
关键词：
dental porcelain abration sintering temperature leucite glass thermal expansion 歯科用陶材焼成温度摩耗特性

项目摘要

X-ray diffractometry (XRD) was used to analyze the crystal phases of three commercial dentin and incisal porcelains prepared by normal cooling, quenching in water, and controlled slow annealing after normal firing. The results suggest that the cooling condition has little effect on the microstructural changes of leucite crystals in the dental porcelains, since the leucite crystals were formed at a higher temperature range than the firing - and cooling- temperature range and were stabilized by incorporation of additives into the lattice.The leucite crystals having modified compositions from stoichiometric one were prepared by the incorporation of Na, Rb, Cs, Ca, Ba, and Sb substituted for 5 -50 at% of K in the leucite. The lattice parameters of a- and c-axes of these tetragonal leucite were derived from the diffraction angles of (400) and (004) peaks due to tetragonal leucite, respectively. It is concluded that the crystal lattice of leucite was deformed by the incorporation of cations … More substituted for K and their variations mainly depend upon the kind of cation, namely ionic size and substitution site in the lattice.Thermal expansion coefficients were determined using a dilatometer on commercial dental porcelains, stoichiometric tetragonal leucite, cesium added cubic leucite, three kinds of glasses, and mixtures of leucite and glass. Thermal expansion coefficients of leucite were also derived from the lattice parameter changes using high temperature X-ray diffractometry. The results suggested that the glass surrounded around leucite particles is required to have a high glass transformation temperature than 650℃ because of the remains of high stress in the surrounded matrix glass.The influences of cubic leucite having various contents, particle sizes, and firing conditions on various properties (biaxial flexure strength, Vicker's hardness, thermal expansion, and abrasion of human enamel) of dental porcelains were investigated. FE-SEM and XRD analyzes revealed that cubic leucite was changed to tetragonal leucite on the boundary between cublic leucite particle and glass matrix by firing. There were no significant differences in the biaxial flexure strengths of the experimental porcelains containing different content of cubic leucite (p<0.05). It is concluded that the flexure strength of feldspathic dental porcelains was independent on the dispersion of cubic leucite, but depended on the dispersion of tetragonal leucite. Vicker's hardness values of the fired specimens containing cubic leucite increased with the particle size of cubic leucite. Thermal expansion coefficient of the fired specimens containing cubic leucite increased with their contents. Contents of cubic leucite had little effect on abrasion rate. Less

采用X射线衍射仪（XRD）对正常冷却、水中淬火和正常烧成后控制缓慢退火制备的三种市售牙本质和切端烤瓷的晶相进行了分析，结果表明，冷却条件对其影响不大。牙科瓷中白榴石晶体的微观结构变化，因为白榴石晶体是在比烧制和冷却温度范围更高的温度范围内形成的，并且通过掺入通过掺入Na、Rb、Cs、Ca、Ba和Sb取代白榴石中5 -50 at%的K来制备具有化学计量组成的修改的白榴石晶体。这些四方白榴石的 - 和 c 轴源自四方白榴石的 (400) 和 (004) 峰的衍射角结论是，白榴石的晶格因取代 K 的阳离子的掺入而变形，其变化主要取决于阳离子的种类，即晶格中的离子尺寸和取代位点。热膨胀系数为使用膨胀计对商业牙科瓷器、化学计量四方白榴石、添加铯的立方白榴石、三种玻璃以及以下物质的混合物进行测定白榴石和玻璃的热膨胀系数也通过高温X射线衍射法的晶格参数变化得出。结果表明，白榴石颗粒周围的玻璃需要具有高于650℃的玻璃化转变温度。周围的基质玻璃中仍然存在高应力。不同含量、粒径和烧成条件的立方白榴石对各种性能（双轴弯曲强度、维氏硬度、热膨胀和FE-SEM 和 XRD 结合研究表明，通过烧成，立方白榴石颗粒与玻璃基质之间的边界处的立方白榴石转变为四方白榴石，并且其双轴弯曲强度没有显着差异。实验瓷中含有不同含量的立方白榴石（p<0.05），得出长石牙科瓷的抗弯强度。含立方白榴石的烧制样品的维氏硬度值与立方白榴石的色散无关，但取决于四方白榴石的色散，随着含立方白榴石的烧制样品的热膨胀系数增加。其含量对磨耗率影响较小。