【作者】 刘霜；

【导师】 张连云； 李长义；

【作者基本信息】 天津医科大学 ， 口腔临床医学， 2010， 硕士

【摘要】 目的：钛以其良好的机械性能、耐腐蚀性和优异的生物相容性在医学领域中得到广泛应用。目前应用于临床的口腔修复材料主要是纯钛及Ti-6Al-4V合金,长期临床应用及研究表明纯钛用于活动义齿机械性能略显不足,临床上常出现卡环断裂等情况。且材料耐磨性较差,铸造、焊接、抛光等加工性能较差；Ti-6Al-4V含有Al及V等潜在毒性元素,限制了钛及其合金在口腔修复领域的应用。因此研制机械性能及生物相容性良好且易进行口腔修复工艺制作的义齿修复支架用钛合金对提高义齿修复质量及扩大修复适应证都是十分必要的。方法：1、合金制备：选用高纯度Ti、Zr、Nb、Sn合金元素,按Ti-12.5Zr-3Nb-2.5Sn(wt%)比例称取原料配制合金,采用高真空电弧熔炼合金。2、机械性能评价。将钛锆铌锡合金制作标准力学试样,经850℃固溶1.5h,500℃时效3h后,采用万能拉伸试验机测试力学性能；采用MH-6显微硬度仪测试合金显微维氏硬度；扫描电子显微镜观察合金显微组织,分析拉伸试样断口形貌；用RIGAKUDMAX型X-射线衍射仪对合金进行物相分析,确定合金金相组织中各相的组成结构及种类；采用金相试验观察合金的微观组织结构。3、生物学性能评价。参照国家制订的口腔医用材料技术报告相关标准,采用细胞毒性试验、急性全身毒性试验、口腔粘膜刺激试验、致敏性试验等体内及体外试验,测定新型钛合金的生物安全性,评价其生物学性能。4、铸造性能评价。制作测试蜡型,按照牙科纯钛镁系包埋材要求包埋,采用国产LZ5型离心铸钛机铸造试样,确定合金的铸造温度,测试合金的铸流率,并评价合金的铸造反应层和线收缩率。结果：1、合金机械性能及组织结构：Ti-12.5Zr-3Nb-2.5Sn合金抗拉强度为671.3±24.7MPa,屈服强度为561.5±39.9 MPa,延伸率为18.1±4.6%,弹性模量为92.5±8.0Gpa,合金硬度为250.7±16.1HV。试样断口处可见明显颈缩现象,肉眼观察呈纤维状,颜色灰暗。SEM显示组织在扩展区形成等轴韧窝,呈典型的微孔聚合型断裂方式。金相结构中晶粒组织均匀,呈现针状a分布于粗大的β晶粒中。XRD显示合金为近α相。2、合金生物学性能：细胞毒性试验显示合金0.2g/ml比例的浸提液,其细胞相对增殖度为124%,细胞毒性反应分级为0级；全身急性毒性试验显示小白鼠经尾部静脉注射给予试验样品浸提液,72h观察期内,其反应症状与对照组相比无明显差异,体重均未出现下降；口腔粘膜刺激试验显示合金固定于地鼠颊粘膜表面14天后,颊粘膜无充血、无肿胀、无糜烂,未见溃疡反应。组织学观察,动物接触供试样品部位粘膜上皮组织完好,无细胞变性、坏死,粘膜下白细胞浸润平均<25个/每高倍视野,血管无充血,粘膜下组织无水肿；致敏性试验显示供试品组及阴性对照组动物皮肤均未出现水肿、红斑等过敏反应,致敏率均为0。3、合金铸造性能：按临床常规操作制作试样蜡型,纯钛镁系包埋材包埋并按纯钛包埋材升温曲线焙烧,400℃时铸造,其铸流率为100%,铸造线收缩率,表面反应层满足修复支架的铸造要求。结论：1、Ti-12.5Zr-3Nb-2.5Sn合金经850℃固溶1.5h,500℃时效3h,机械性能较纯钛明显提高,能够满足口腔修复支架用金属材料的性能要求。2、生物学试验表明,合金的细胞毒性反应为0级,全身毒性试验中未见急性毒性反应,对口腔粘膜无刺激性,无皮肤致敏反应,具有良好的生物相容性。3、该合金铸造时表面反应层和铸造线收缩率能够满足口腔修复支架的精度要求。加工出的铸造支架及口盖铸件完整,模型上就位顺利,打磨及抛光性能良好。更多还原

【Abstract】 Objective:Titanium was widely used for its good mechanical, corrosion- resistance and biological properties. Titanium and Ti-6Al-4V are mostly used in dental restoration field. Considering the low tensile strength, bad wear resistance, and difficulties in processing technology of the titanium in the current clinical applications and researches, loop fracture offen appears in clinical medicine, Ti-6A1-4V contain Al&V, which restricted its application in the field of prosthodontics. Therefore, it is necessary to develop a new type of titanium alloy for dental restoration with better mechanical properties, biocompatibility and easy to process, which can enhance the effect of dental reparation and to expand the indications in the dental restoration.Methods:1. Preparation of alloy: Ti, Zr, Nb, Sn were selected as alloy elements. According to proportion of Ti-12.5Zr-3Nb-2.5Sn (wt%), raw materials were weighed and alloy was prepared by high vacuum arc melting alloy.2. Evaluation of mechanical properties. Ti-Zr-Nb-Sn alloy was made into standard samples, the mechanical properties was tested by universal tensile test machine after quenching process at 850℃for 1.5 hours and aging treatment at 850℃for 3 hours; Micro Vickers hardness was tested by MH-6 micro-hardness tester; the microstructure and the fracture morphology were scanned and observed by electron microscope; the alloy microstructure was analyzed with X-ray diffraction phase.3. Evaluation of biological performance. According to correlative standards, a series of in vivo and in vitro tests, such as the cell toxicity test, toxicity test, oral mucosa stimulate experiment and sensitization experiments was made to study the biological safety of the new titanium alloys and evaluate its biological properties.4. Evaluation of casting performance. Produced wax type tester, embedded as embedding materials, cast by LZ5-centrifugal casting machine, to study casting temperature of the titanium alloy and to test the alloy casting flow rate, evaluation of alloy casting reaction layer and linear shrinkage.Results: 1. Organizational structure and mechanical properties. The tensile strength, yield strength, elongation, elastic modulus and hardness of alloy were 671.3±24.7MPa, of 561.5±39.9 MPa,18.1±4.6%,92.5±8.0Gpa,250.7±16.1HV respectively. It clearly showed necking phenomenon, fibrous by naked eye, the color gray. Specimen fracture electron microscopy revealed the formation of organizations in the expansion area. In the metallographic structure, it was showed that the distribution of needle-like a in the thick ofβgrains. XRD display alloy was nearlyα-Ti.2. Biological properties. Cytotoxic test showed that the degree of cell relative proliferation was 124% and cell toxicity grading was grade 0; Systemic acute toxicity test showed no significant differences in reaction symptom and body weight compared with the control group after 72h; Oral mucous membrane irritation test showed no buccal congestion, no swelling, no erosion, no ulcer reaction when alloy was fixed on hamster buccal surface for 14 days. Histological observation found no adverse reaction at the tested sample area animal contact with; Sensitization experiments showed no skin edema, erythema or other allergic reactions on the test sample group and negative control animals. Sensitization rate was 0.3. Casting properties. Samples were waxed, embedded and roasted by demand, cast at 400℃. The casting flow rate was 100%. Linear shrinkage and the surface reaction layer met the demand.Conclusions:1. The mechanical properties was prior to Titanium obviously, after quenching process and aging treatment and the former could meet the performance demand to the metal material used for oral restoration.2. Biology experiment showed that the alloy cytotoxicity reaction level was 0; no acute toxic reactions, irritation to the oral mucosa, or skin sensitization.3. The surface reaction layer and linear shrinkage met the accuracy requirements of dental demands. The casting stand and flap were complete. The model emplacement, grinding and polishing were excellent.更多还原