【作者】 赵鹃；

【导师】 赵云凤；

【作者基本信息】 四川大学 ， 口腔临床医学， 2004， 博士

【摘要】 钛具有生物相容性良好、耐腐蚀、比强度大、无金属离子味等优点,被公认为是生物金属。真空铸造是口腔钛修复体最常用的加工方法。研制新的包埋料和适宜的铸造工艺,才能制作出高质量牙科铸钛修复体。本课题是前期自制铸钛包埋材料研究工作的继续,在前期材料学研究的基础上,综合考察自制包埋料及其钛铸件的多方面性能,探索自制铸钛包埋材料的铸造工艺及相关参数,为自制铸钛包埋材料的临床应用提供较完善的技工操作规范。另外,对利用尖晶石生成反应的颗粒尺寸效应提高包埋料热膨胀率,以及将三维测量技术引入口腔修复可摘义齿适合性测量领域进行初步探索。 本课题第一部份采用金相显微镜、扫描电镜、能谱分析仪、万能试验机、体视显微镜等,研究了自制铸钛包埋材料的铸模温度、铸造后冷却方式和包埋方式对钛铸件的流铸率、反应层、力学性能、全冠铸造精度等的影响。结果显示:采用600℃铸模温度、一次包埋法和自然冷却方式,铸钛全冠有良好的适合性,虽然600℃铸模温度钛铸件的表面反应层较厚(115μm),但经过喷砂处理去除反应层后,钛冠各部位的适合性均小于120μm,达到临床要求,而且,600℃铸模温度钛铸件的规定非比例延伸强度350.67MPa,抗拉强度477.50MPa,断后延伸率20.75%,在可接受范围内;骤冷方式钛铸件的表面反应层厚100μm,强度较自然冷却组小,但延伸率无差异,而且其全冠适合性未达到临床要求(>1204μm);一次性包埋法更多还原

【Abstract】 Titanium is regarded as biological metal for its advantages of good biocompatibility, corrosion resistance, great specific strength, etc. Vacuum cast is the most common method to produce dental titanium restorations. Investment with high quality and proper cast technology are essential to well-qualified titanium castings. This research was based on knowledge of the foregoing material study of a self-made investment for titanium. The primary purpose of this research was to find out proper cast technology of the new investment for its possible clinical application. Moreover, there were two other aims: to investigate if thermal expansion could be enhanced by way of granular size effect of spinel formation and to measure fit of removable partial denture (RPD) by three-dimensional measurement technique.In the first part, by metallographic microscopy, SEM (scanning electric microscopy), EDX (energy dispersive X-ray analysis), a mechanical testing machine and a stereomicroscope, the influence of mould temperature, cooling method and investing method on castability, reaction layer, mechanical properties and fit of titamum castings were investigated. The results indicated that titanium full crowns by 600℃ mould temperature , bench cooling and one-step investing exhibited better and clinically acceptable fit, that is, although its titanium castings exhibited 115μm thick reaction layer, the full crowns exhibited marginal and internal fit less than 120μm after sandblasting, and the mechanical properties were acceptable (0.2 proof strength 350.67MPa, tensile strength 477.50MPa, and percentage elongation after fracture 20.75%); titanium full crowns by 600℃ mould temperature and quenching in roomtemperature water exhibited fit beyond the clinically acceptable range (> 120pm ); titanium full crowns by 600X1! mould temperature and two-step investing also exhibited fit more than 120um and were not clinically acceptable.In the second part, by use of a thermal dilatometer and XRD (X-ray diffractometer), the influence of reduced AI2O3 particle sizes on thermal expansion ratio of the MgO/ AI2O3 investment was observed. The results showed that, although well powder processed investment had good manipulating properties, it was not seemed that the thermal expansion could be enhanced by reduction of AI2O3 particle sizes.In the third part, the casting accuracy of titanium RPD frameworks made from the investmerit was calculated by two ways: one to measure dimensional changes of the frameworks by a measuring microscope, and the other to measure the fit between the base of a framework and its model surface by a three coordinate measuring machine (3CMM). The results showed that the titanium RPD frameworks exhibited dimensional constriction, i.e. AD 1.235%, AE 0.9825%, BC 1.245%, and DE 1.188%, which were similar to the results of other researchers; and the average fit of RPD base was less than 200um and clinically acceptable.In conclusion, to made titanium full crowns and RPD frameworks with good comprehensive qualities (especially with clinically acceptable casting accuracy) , the self-made investment should be manipulated with 600 "C mould temperature , bench cooling and one-step investing; by dental titanium casting technology at present, it was not seemed that thermal expansion of the investment could be enlarged by way of granular size effect of spinel formation; the laser scanning 3D measuring method provided a new, nondestructive, accurate and full-scale way for fit measurement of RPDs.更多还原