牙科纳米氧化锆陶瓷粉体的制备

目的 :探讨用于增韧牙科氧化铝陶瓷的纳米氧化锆陶瓷粉体的制备方法。方法 :应用沉淀法 ,比较不同前驱物浓度和 pH值等条件下 ,所制备氧化锆粉体的物理性能。 结果 :ZrOCl2 ·8H2 O浓度为 0 .3～ 0 .5mol/L、pH 8.5时 ,经 70 0℃煅烧 2h后 ,可获得性能优良、粒径约为 10 0nm的氧化锆陶瓷粉体。 结论 :选择适当的条件 ,该方法可制得粒径小、团聚少的纳米氧化锆陶瓷粉体。     

氧化锆质量分数对牙科复相铝瓷强度和断裂韧性的影响

目的测定所制备的牙科氧化锆增韧复相铝瓷（ZTCA）的力学性能,探讨氧化锆质量分数变化对ZTCA力学性能的影响及其增韧机制。方法溶胶- 凝胶法制备单相Al2O3粉体,表面诱导沉淀法制备4组不同ZrO2质量分数的ZTCA粉体。将5组粉体干压成型后烧结并加工成标准试件用于力学性能试验,测定三点弯曲强度及断裂韧性;扫描电子显微镜观察基体断口形貌;X射线衍射分析ZTCA基体晶相组成。结果ZTCA抗弯强度随ZrO2的增加先上升而后下降;ZrO2加入量为30%时,抗弯强度最高,为304.5 MPa,对应的断裂韧性为1.85 MPa·m1/2;ZTCA基体晶相包括α- Al2O3、四方相氧化锆以及少量的单斜相氧化锆。结论ZrO2质量分数不同对应ZTCA的强韧化机制不同,ZrO2质量分数为15%～30%时,材料以应力诱导相变增韧为主;ZrO2质量分数大于30%时,还存在微裂纹增韧机制。     

氧化锆增韧的纳米复合渗透陶瓷（AlO3—nZrO2）粉体合成的研究

目的 研究AlO3-nZrO2纳米复合陶瓷粉体的合成。方法 采用包裹共沉淀与湿法球磨相结合的方法合成AlO3-nZrO2纳米复合陶瓷粉体。结果 （1）采用观察沉降情况与沉降物体积的方法来评价分散效果，粉体分散系沉降过程极慢，观察24h后悬浮液的颗粒仍由上而下呈逐渐增浓的弥散分布，最后即使经高速离心所得到的沉积物体积亦较小。（2）SEM观察粉体颗粒分散较好，超细颗粒粒径为纳米级。（3）衍射图剖析结果经稳定剂处理后，粉体晶相由单斜盯和四方相共同构成，即成为有增韧作用的部分稳定ZrO2粉体。结论 所合成AlO3-nZrO2粉体的分散效果，粉浆流动性良好且适于操作。     

粉浆涂塑铝瓷冠铝瓷粉浆分散剂的研究

粉浆涂塑铝瓷冠是新近推出的一种全瓷修复系统，具有强度高、边缘适合性好透光性好等诸多优点。它是通过涂塑铝瓷粉浆于专用代型表面成型的，制备性能良好的铝瓷粉浆是获得高强度铝瓷冠的重要前提。本研究采用沉积百分含量为铝瓷粉浆分散效果的评判指标，对ＧＩ－Ｉ型粉浆涂塑铝瓷粉浆分散剂的分散性能及使用条件进行了研究。结果表明，粉浆涂塑铝瓷核冠铝瓷粉浆分散剂在碱性环境下具有良好的分散性能，并且加入量小，仅需０．２￣０     

氧化锆增韧的纳米复合渗透陶瓷(Al2O3-nZrO2)粉体合成的研究

目的　研究Al2 O3 -nZrO2 纳米复合陶瓷粉体的合成。方法　采用包裹共沉淀与湿法球磨相结合的方法合成Al2 O3 -nZrO2 纳米复合陶瓷粉体。结果　①采用观察沉降情况与沉降物体积的方法来评价分散效果 ,粉体分散系沉降过程极慢 ,观察 2 4h后悬浮液的颗粒仍由上而下呈逐渐增浓的弥散分布 ,最后即使经高速离心所得到的沉积物体积亦较小。②SEM观察粉体颗粒分散较好 ,超细颗粒粒径为纳米级。③衍射图剖析结果经稳定剂处理后 ,粉体晶相由单斜相和四方相共同构成 ,即成为有增韧作用的部分稳定ZrO2 粉体。结论　所合成Al2 O3 -nZrO2 粉体的分散效果、粉浆流动性良好且适于操作     

反向沉淀法制备牙科纳米氧化锆粉体

目的 制备分散性好，粒度分布均匀的纳米级zrO2粉体。方法 以乙醇为溶剂，应用反向沉淀法，制备纳米级zrO2粉体并测试其性能。结果 前驱体粉体经600℃煅烧后，得到晶粒平均粒径为D101=15．39nm的以四方相为主的纳米级ZrO2粉体，经800℃、1000℃煅烧后，分别得到晶粒平均粒径为D111=27．29nm和D111=28．86nm的单斜相zrO2粉体。结论 以乙醇为溶剂，应用反向沉淀法可制备出分散性好、粒度均匀的纳米级zrO2粉体，低表面张力的乙醇为溶剂可以产生良好的“反团聚”效果。     

牙科用Ce—Y—Mg复合稳定氧化锆增韧陶瓷的基本性能

目的：探讨牙科用Ce-Y-Mg复合稳定氧化锆增韧陶瓷（zirconia toughened ceramic,ZTC)的基本性能。方法：化学共沉淀法制备的三元复合稳定（Ce-Y-Mg）氧化锆粉体造粒后，经双相干压成型，1350℃烧结，磨光并抛光后测试其物理和力学性能。结果；三元复合稳定（Ce-Y-Mg）氧化锆增韧陶瓷烧结后密度为6.01g/cm^3，是理论密度的98．52％，三点弯曲强度为709Mpa，断裂韧性为11.6MPam^1/2。结论：Ce-Y-Mg复合稳定剂可以对氧化锆陶瓷起到很好的增韧效果；Ce-Y-Mg复合稳定氧化锆增韧陶瓷强度高，韧性好，力学性能能够满足牙科桩钉标准。     

牙科纳米氧化铝陶瓷粉体的制备

目的:探讨牙科纳米氧化铝陶瓷粉体的制备工艺。方法:应用溶胶-凝胶法,比较不同前驱物浓度、pH 值、热处理温度及时间等条件下所制备氧化铝粉体的物理性能。结果:Al (NO3 ) 3 ·9H2O 溶液浓度为011 molPL、pH = 9时,经1200 ℃煅烧10 min 后,可获得性能优良、粒径约为70 nm的氧化铝陶瓷粉体。结论:选择适当的反应条件可制得粒径小、团聚少的纳米氧化铝陶瓷粉体。     

氧化锆/磷酸镧可切削复相陶瓷的制备及机械性能研究

目的 利用氧化锆粉体和磷酸镧粉体复合,制备可用于制作牙科修复体并适合牙科加工的氧化锆陶瓷。通过调整原料的成分、配比、添加稳定剂并对材料进行机械性能研究,以期获得一种满足牙科修复体要求的可切削氧化锆/磷酸镧复相陶瓷。方法 通过对氧化锆/磷酸镧复相陶瓷抗弯强度、断裂韧性、维氏硬度、X线衍射显微结构分析等方面的检测分析,来确定氧化锆/磷酸镧复相陶瓷的成分配比以及工艺参数。结果 10%磷酸镧含量组1%稳定剂(Y2O3)加入量时机械性能最佳,抗弯强度(590.36±45.67)MPa,断裂韧性(6.62±0.51)MPa.m1/2;20%磷酸镧含量组3%Y2O3加入量时机械性能最佳,抗弯强度(568.91±28.72)MPa,断裂韧性(3.79±0.13)MPa.m1/2;30%磷酸镧含量组5%Y2O3加入量时机械性能最佳,抗弯强度(405.90±18.06)MPa,断裂韧性(2.46±0.08)MPa.m1/2;40%磷酸镧含量组7%Y2O3加入量时机械性能最佳,抗弯强度(200.90±14.46)MPa,断裂韧性(2.1±0.12)MPa.m1/2。结论 新型牙科氧化锆/磷酸镧复相可切削陶瓷材料烧结制备性能良好,机械性能优良。     

纳米氢氧化锆涂层对10-甲基丙烯酰氧癸二氢磷酸酯提高氧化锆陶瓷粘接强度的影响

目的 研究纳米氢氧化锆在氧化锆陶瓷表面形成碱性涂层后对10-甲基丙烯酰氧癸二氢磷酸酯（MDP）与氧化锆陶瓷粘接强度的影响。方法 制作氧化钇稳定四方相氧化锆（Y-TZP）瓷片140枚,氧化铝喷砂后对其表面进行不同的处理,制作粘接试件并测试剪切粘接强度。以X线光电子能谱（XPS）检测Y-TZP陶瓷表面依次经过纳米氢氧化锆涂层和含有MDP的底涂剂处理后的化学键变化。结果 老化前,与对照组相比,两种碱性涂层均能提高短期粘接强度值,纳米氢氧化锆涂层增强效果更显著。老化后,各组粘接强度值差异无统计学意义,但较老化前均显著降低（P<0.05）。XPS在制备纳米氢氧化锆涂层的Y-TZP瓷片表面检测到-OH键,在制备纳米氢氧化锆涂层的Y-TZP陶瓷应用含有MDP的底涂剂处理后检测出-P-O-Zr键。结论 在氧化锆陶瓷表面制备碱性涂层能够使MDP提高氧化锆陶瓷粘接强度。     

Mechanical Properties of a new Dental all-ceramic Material-zirconia Toughened Nanometer-ceramic Composite

目的口腔全瓷修复体以其独特优越性受到医患青睐,但脆性问题一直限制其应用范围及使用可靠性.本研究旨在研制用于玻璃渗透全瓷修复的纳米氧化锆增韧陶瓷并全面检测评价其力学性能.方法采用化学共沉淀与球磨相结合的方法合成纳米氧化锆增韧陶瓷(α-Al2O3/nZrO2 ceramics powder ,W),扫描电镜评价陶瓷材料的粉体形态特征及粒度分布.预制氧化锆含量不同的陶瓷粉体(5wt%,10wt%,15wt% and 20wt%),采用粉浆涂塑技术将材料制成标准试件,并在不同温度下(1 200～1 600 ℃)烧结成型,用三点弯曲法及单边刀口梁法检测材料试件的抗弯强度和断裂韧性.结果1)α-Al2O3/nZrO2材料粉体粒度分布范围大致为0.02～3.0 μm,其中超细粉体(低于0.1 μm)占20%; 2)不同烧结温度组试件的力学强度有显著差异(P＜0.05),1 450 ℃和1 600 ℃组高于1 200 ℃组;3)相同烧结温度下不同氧化锆含量组材料强度有显著差异,一定范围内氧化锆含量增高有助于材料的增韧增强.结论本研究所研制的纳米氧化锆增韧陶瓷材料组分配比及微观特征能增韧增强材料,有望提高玻璃渗透后材料的综合力学性能.     

硅涂层对牙科氧化铝陶瓷与树脂粘结强度的影响

目的 探讨在牙科氧化铝陶瓷表面进行SiO2水溶胶涂层对陶瓷与树脂粘结强度的影响.方法 32个氧化铝陶瓷试件根据计算机产生的伪随机数字表分为4组,每组8个,采用溶胶-凝胶法在试件表面分别进行20%SiO2水溶胶涂层+硅烷偶联剂(A组)、30%SiO2水溶胶涂层+硅烷偶联剂(B组)、40%溶胶涂层+硅烷偶联剂(C组)和硅烷偶联剂(对照组)处理,应用傅立叶红外光谱、扫描电镜、X射线能谱仪进行分析.制作陶瓷-复合树脂粘结体,剪切法测试各组剪切粘结强度.结果 溶胶-凝胶法可在氧化铝陶瓷试件表面制得纳米硅涂层.热处理后A、B、C 3组试件Si-O-Si反对称伸缩振动吸收峰、对称伸缩振动吸收峰、弯曲振动吸收峰均增强;扫描电镜显示纳米氧化硅粒子分布较均匀,局部粒子产生团聚;试件表面硅元素含量均明显增加.A、B、C组试件与树脂的剪切粘结强度分别为(3.196±0.171)Mpa、(4.852±0.178)Mpa、(3.576±0.671)Mpa,与对照组[(1.881±0.156)Mpa]相比,差异均有统计学意义(P＜0.05);B组的剪切粘结强度与A、C组相比,差异有统计学意义(P＜0.05).结论 3种浓度硅溶胶可在牙科氧化铝陶瓷表面制得纳米硅涂层.纳米硅涂层可显著提高氧化铝陶瓷与树脂的剪切粘结强度.其中30%浓度SiO2水溶胶制备的硅涂层提高剪切粘结强度的效果最明显.     

Aging resistant ZTA composite for dental applications: Microstructural,optical and mechanical characterization

ObjectiveTo synthesize a zirconia toughened alumina (ZTA) composite with 70% alumina reinforced by 30% zirconia for dental applications and to characterize its microstructure and optical properties for comparison with the isolated counterpart materials and a first-generation 3Y-TZP.MethodsDisc-shaped specimens were divided in four groups (n = 70/material): (1) 3YSB-E (first generation 3Y-TZP), (2) Zpex (second generation 3Y-TZP), (3) alumina, and (4) ZTA-Zpex 70/30. After synthesis, ceramic powders were pressed, and green-body samples sintered following a predetermined protocol. Specimens were polished to obtain a mirror surface finish. Apparent density was measured by Archimedes principle. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the crystalline content and microstructure. Reflectance tests were performed to determine the contrast-ratio (CR) and translucency-parameter (TP). Mechanical properties were assessed by biaxial flexural strength (BFS) test. All analyses were conducted before and after artificial aging (20 h, 134 °C, 2.2 bar). Optical parameters were evaluated through repeated-measures analysis of variance and Tukey tests (p < 0.05). BFS data were analyzed using Weibull statistics (95% CI).ResultsHigh density values (95–99%) were found for all ceramic materials and SEM images exhibited a dense microstructure. While XRD patterns revealed the preservation of crystalline content in the ZTA composite, an increase in the monoclinic peak was observed for pure zirconias after aging. Significantly higher CR and lower TP values were observed for the ZTA composite, followed by alumina, 3YSB-E, and Zpex. The highest characteristic stress was recorded for 3YSB-E, followed by intermediate values between ZTA and Zpex, and the lowest for alumina. Aging affected the optical and mechanical properties of both zirconias, while remained stable for ZTA composite and alumina.SignificanceThe synthesis of experimental 70−30% ZTA composite was successful and its relevance for dental applications relies on its higher masking ability, aging resistance, and strength similar to zirconia.     

Damage accumulation and fatigue life of particle-abraded ceramics

PURPOSE: This investigation compared initial and fatigue strengths of particle-abraded ceramics to those of as-polished alumina and zirconia ceramics in crown-like layer structures. MATERIALS AND METHODS: Alumina or zirconia plates bonded to polycarbonate substrates were subjected to single-cycle and multi-cycle contact (fatigue) loading. Cementation surfaces of the ceramic were damaged by controlled particle abrasion, indentation with a sharp diamond at low load, or a blunt indenter at high load. The stresses needed to initiate radial fractures were evaluated. RESULTS: The strengths of specimens were lowered by fatigue loading. After the equivalent of 1 year of occlusal contacts, the strengths of undamaged specimens degraded to approximately half of their single-cycle values. In particle-abraded specimens, an additional 20% to 30% drop in strength occurred after several hundred load cycles. Particle abrasion damage was approximately equivalent to damage from sharp indentation at low load or blunt indentation at high load. CONCLUSION: Damage from particle abrasion, not necessarily immediately apparent, compromised the fatigue strength of zirconia and alumina ceramics in crown-like structures. In fatigue, small flaws introduced by particle abrasion can outweigh any countervailing strengthening effect from compression associated with surface damage or, in the case of zirconia, with phase transformation.     

溶胶凝胶自组装法硅涂层对氧化锆陶瓷与树脂短期粘结强度的影响

目的　评价溶胶凝胶自组装法硅涂层对氧化锆陶瓷与树脂短期粘结强度的影响。方法　加工56 个氧化锆瓷块并随机分为4 组,分别对粘结面进行以下处理：A组：硅烷偶联剂;B组：溶胶凝胶浸涂1层硅涂层+硅烷偶联剂;C组：溶胶凝胶自组装2层硅涂层+硅烷偶联剂;D组：溶胶凝胶自组装3层硅涂层+硅烷偶联剂。制作56 枚光固化复合树脂圆柱并用树脂水门汀粘结于预处理后的氧化锆瓷块上,水浴24 h 后测试剪切粘结强度。以扫描电镜和表面能谱分析对不同表面处理的氧化锆进行表征分析,体视显微镜记录样品断裂模式。结果　A组到D组各组剪切粘结强度值分别为（3.05±0.26）MPa,（6.83±0.33）MPa、（10.51±0.58）MPa和（7.72±0.35）MPa。除B组和D组无统计学差异外,其余各组之间均具有统计学意义(P=0.000)。其中溶胶凝胶自组装2层硅涂层获得的剪切粘结强度值最大。结论　溶胶凝胶自组装法硅涂层可以提高氧化锆陶瓷表面粘结强度,其中溶胶凝胶自组装2层硅涂层组的效果最好。     

Effects of bur abrasive particle size and abutment composition on preparation of ceramic implant abutments

STATEMENT OF PROBLEM: Amid increasing use of preparable ceramic implant abutments, there is a lack of quantitative data to show which abrasive particle size of diamond bur yields the fastest reduction and provides the smoothest surface. PURPOSE: The research aim was to determine the effects of diamond bur abrasive particle size and abutment material composition on preparation efficiency, prepared surface roughness, and surface deterioration of diamond burs. MATERIAL AND METHODS: Fifteen alumina (Cera Base) and 15 zirconia (ZiReal) implant abutments were each machined using a high-speed hand piece with a diamond bur having 1 of 3 abrasive particle sizes (150, 100, or 30 microm) (n=5). Control abutments (n=5) were analyzed without machining. Abutments were weighed before starting and between machining cycles. Three profilometry measurements (root mean square surface roughness) were made for each abutment. Scanning electron micrographs were made of each bur. Lost abrasive particles were then counted on each micrograph through a randomly placed template. Two-way analysis of variance (alpha=0.05) was used to test for significant effects. RESULTS: Bur abrasive particle size and ceramic type had a significant interactive effect on the amount of material removed (P<.001). Super coarse (150 microm) burs yielded the roughest surfaces for each abutment material (P<.001), and prepared alumina surfaces were rougher than zirconia surfaces (P<.001). Super coarse burs showed the highest proportion of lost particles (P<.001). Abutment composition did not significantly affect bur wear. CONCLUSION: Super coarse burs yielded the most efficient material removal for alumina abutments. All abrasive particle sizes removed a similar amount of material from zirconia abutments. Fine-grained alumina abutments experienced greater material removal and rougher prepared surfaces compared with zirconia abutments. Material was removed by an intergranular fracture mechanism for alumina abutments, in contrast to transgranular fracture for zirconia abutments.     

氧化铝预烧结前后及玻璃渗透后渗透陶瓷的扫描电镜观察

目的：渗透陶瓷是一种新型的高强度全瓷冠桥修复材料,本实验研究了渗透陶瓷在氧化铝预烧结前后及四种玻璃料渗透后陶瓷样本的ＳＥＭ表现,旨在探讨高强度的可能原因,以及微观结构与强度的关系。方法制取氧化铝预烧结前、后及ＧＩ－Ⅰ型、ＧＩ－Ⅱ型镧系、ＧＩ－Ⅱ型铈系、Ｖｉｔｚ Ｉｎ－ｃｅｒａｍ玻璃渗透后的样本各１个,进行ＳＥＭ观察,结果Ｖｉｔａ Ｉｎ－ｃｅｒａｍ氧化铝粉的颗粒大小具有多相性,其中大颗粒粒度为３－５μｍ,小颗粒粒度为０．１－０．５μｍ,烧结以的小颗粒的数目略减小,氧化铝基体的致肖增加;４种玻璃渗透以后样本的断面ＳＥＭ相似,渗透后氧化铝颗粒稍长大,形态有向氧化铝的天然晶型斜方型转化的趋势。结论玻璃渗透过程中,可能发生了小颗粒氧化铝的溶解再晶化过程,强度相同的四种渗透陶瓷ＳＥＭ表现也相似。     

Influence of modifying and veneering the surface of ceramic abutments on cellular attachment and proliferation

Objectives: This in vitro study was aimed to investigate the attachment, spreading and proliferation of human gingival fibroblasts to milled and polished non‐veneered ceramic surfaces in alumina and zirconia and to ceramic surfaces veneered by two different types of porcelain baseliners. Materials and methods: Fibroblasts were cultured on discs of pressed alumina or zirconia, on discs which had been milled, on discs comprising alumina or zirconia which had been polished, on discs of alumina veneered with NobelRondo baseliner Al, on discs of zirconia veneered with Cercon‐S baseliner, and on alumina or zirconia discs veneered with the above baseliners and then polished. The surfaces were analyzed using an optical interferometer and scanning electron microscopy (SEM). Cell profile areas were measured using SEM and an image analyzer. Cell attachment was determined after 3 and 24 h as a ratio of the cell profiles and the total micrograph area and was expressed as percent of attachment. MTT analyses were undertaken to determine cellular attachment after 3 h of incubation and cellular proliferation after 7 days. Results: The polished zirconia specimens had the smoothest surface in terms of average height deviation (S_a=0.03 μm): the roughest were the zirconia specimens with milled surfaces (S_a=0.36 μm). The application of the baseliners resulted in surfaces smoother than those of the non‐veneered discs. The milled surfaces of both alumina and zirconia had significantly higher percentages of cell attachment and proliferation than the other surfaces whereas the milled surfaces in zirconia demonstrated better cellular attachment after 3 and 24 h of culture than the one in alumina. Fibroblasts attached and grew effectively on the surfaces veneered with NobelRondo throughout the experiments, whereas the zirconia surfaces veneered with Cercon‐S had the lowest percentage of cell attachment and proliferation. Conclusions: Although the roughness of all surfaces investigated was <0.4 μm, the study disclosed significant differences in cellular attachment and proliferation associated with the various surface modifications.