牙科全瓷材料3Y-TZP粉体粒度对烧结性能与微观结构的影响

目的:探讨不同粉体粒度对全瓷材料3Y-TZP烧结性能与微观结构的影响。方法:选取不同粒度的A、B两种高纯纳米3Y-TZP材料,采用模压成型,常压烧结工艺制备试件,然后采用Archimedes法测量烧结线收缩率,气孔率,吸水率,计算体积密度,相对密度等烧结性能指标,并检测试件的微观形貌和物相组成。结果:以B粒度纳米粉制备的3Y-TZP陶瓷材料的烧结温度为1500℃,相对密度98.7%,比A粒度纳米粉制备的材料烧结温度低100℃左右,致密度高1.2%,且色泽优于A粉体烧结试件;微观结构上B材料烧结体晶粒细小,均匀致密,少见气孔、微裂纹等缺陷相;物相组成上,B材料纳米粉烧结试件断面的应力诱发相变所导致的四方相含量变化率也高于A材料烧结试件。结论:纳米粉体B制备的试件烧结温度较低,烧结性能优于A粉体制备的试件,微观结构均匀致密,断裂相变率较高,提示B纳米粉体制备的3Y-TZP材料更适宜作为全瓷桥的支架材料。     

Al2O3-氮化硼纳米晶包覆的3%氧化钇稳定的四方氧化锆多晶复合陶瓷粉体的制备

目的 研究非均相沉淀法制备3%氧化钇稳定的四方氧化锆多晶陶瓷(3Y-TZP)/3%Al₂O₃复合粉的最佳pH值;3Y-TZP/3%Al₂O₃/10%BN双相包覆中,合成Al₂O₃及非晶氮化硼（BN）的最佳热处理温度。方法 不同pH值（6.5、7.5、8.5、9.5）下,通过非均相沉淀法合成Al₂O₃前驱体包覆3Y-TZP粉,通过透射电镜（TEM）选出包覆形貌较均匀的一组。将此pH下制备的复合粉经不同的温度（800、1 000、1 200、1 400 ℃）处理后,硼酸尿素反应烧结法（N₂保护下,850 ℃煅烧5 h,850 ℃煅烧3 h及800 ℃煅烧5 h,800 ℃煅烧3 h）合成10%BN包覆3Y-TZP/3%Al₂O₃粉,通过TEM、能谱分析及X射线衍射（XRD）选出形貌及相组成最佳的一组。结果 当pH值为8.5时,3%Al₂O₃前驱体均匀地包覆在3Y-TZP颗粒周围;3%Al₂O₃前驱体经1 200 ℃煅烧,再包覆10%BN,在N₂保护下800 ℃煅烧5 h,此时可见3Y-TZP颗粒周围包覆Al₂O₃及非晶BN,3Y-TZP/3%Al₂O₃/10%BN复合粉中Al-B-O化合物较少,且t-ZrO₂所占的比例最多。结论 合成Al₂O₃前驱体包覆3Y-TZP的最佳pH值为8.5;双相包覆中,Al₂O₃前驱体的最佳处理温度为1 200 ℃,合成非晶BN的适宜条件为N₂保护下800 ℃煅烧5 h。     

两种着色氧化物对氧化锆陶瓷的颜色影响

目的:选取适合的2种着色金属氧化物对氧化锆粉体(3Y-TZP)进行着色,系统的研究2种着色金属氧化物对氧化锆最终的颜色性能影响。方法:在氧化锆粉体中,加入不同质量分数Fe2O3、CeO2粉体,将粉体装入模具,200MPa冷等静压成型,常压烧结后制得终烧体。从终烧体上切取瓷片,每组5个,使用VITAEasyshade比色仪进行颜色测定,得到瓷片的颜色色度值。结果:添加CeO2后材料的明度为85左右,a*值稍有降低,颜色色调向黄绿色相偏移。添加Fe2O3能显著降低氧化锆陶瓷(3Y-TZP)明度,使材料色调向黄红色相偏移。结论:着色金属氧化物能够赋予氧化锆陶瓷所需的色度值,对氧化锆陶瓷的其他性能影响,尚待进一步研究。     

牙科用可切削云母基玻璃陶瓷析晶行为研究

目的:采用阶梯烧结法制备K2O-MgO-Al2O3-SiO2-F系列玻璃陶瓷,分析不同热处理工艺对所制玻璃陶瓷性能的影响。方法:通过X射线衍射(XRD)、扫描电子显微镜(SEM)、背散射(BSE)及抗弯强度测试,研究氟硅云母玻璃陶瓷的析晶行为特点。结果:680℃核化1 h后,若在1 000~1 120℃之间晶化,则析出主晶相为四氟硅云母,晶体形状由颗粒状逐渐变成立方状或扁平状。陶瓷在大于1 160℃晶化出现晶体熔化。结论:680℃核化1 h后,1 040℃析出的云母晶体符合材料的微观要求,过高的温度不利于云母晶体的析出;二次融入3%的四方氧化锆多晶体(Y-TZP)完全熔解于K2O-MgO-Al2O3-SiO2-F玻璃系统中。     

稀土氧化物着色钇稳定四方多晶氧化锆陶瓷与饰面瓷匹配性的研究

目的:探讨通过添加稀土氧化物着色剂而制备的钇稳定四方多晶氧化锆陶瓷与饰面瓷的匹配性。方法:以稀土氧化物(Pr6O11,CeO2,Er2O3)和过渡元素氧化物(MnO2)为着色剂,采用粉体掺杂方法,在四方多晶氧化锆陶瓷粉体中添加不同质量分数的着色剂,制备出6组钇稳定四方多晶氧化锆陶瓷,测定其与Vita VM9饰面瓷的抗热震性能及界面结合强度。采用SAS6.12软件包对数据进行单因素方差分析。结果:6组钇稳定四方多晶氧化锆陶瓷与Vita-VM9饰面瓷烧结后,各组在60℃～240℃测试过程未发现径向或层间开裂或裂纹现象,加热温度>240℃。6组钇稳定四方多晶氧化锆陶瓷与VitaVM9饰面瓷界面的抗剪切强度值为(36.03±3.82)～(37.98±4.89)MPa,均高于纯四方氧化锆陶瓷组的剪切强度值,但各组与纯四方氧化锆陶瓷的抗剪切强度值无显著差异(P>0.05)。结论:稀土氧化物着色钇稳定四方多晶氧化锆陶瓷与饰面瓷的匹配性达到临床应用水平。     

着色剂对口腔修复用钇稳定氧化锆 陶瓷粉体制备的影响

目的 探讨着色剂氧化铁（Fe2O3）、氧化铈（CeO2）对口腔修复用钇稳定氧化锆陶瓷（Y-TZP）制备粉体的影响。方法 按照一定比例将口腔修复用Y-TZP粉体和着色剂（Fe2O3 0.15%或CeO2 4%）分别混合,配置成具有一定固含量的Y-TZP喷雾干燥浆料。通过喷雾造粒的方法进行着色和未着色Y-TZP粉体造粒。粉体分成3组,分别为未着色Y-TZP组、0.15%Fe2O3着色Y-TZP组、4%CeO2着色Y-TZP组,分别利用激光粒度分析仪和光学显微镜进行3组粉体粒径和形貌的测量和分析。结果 3组口腔修复用Y-TZP造粒粉体的颗粒D50总体均数差异有统计学意义（P<0.05）。均数两两比较时,0.15%Fe2O3着色Y-TZP粉体D50与未着色Y-TZP粉体、4%CeO2着色Y-TZP粉体D50均数差异有统计学意义（P<0.05）;未着色Y-TZP粉体与4%CeO2着色Y-TZP粉体D50均数差异无统计学意义（P>0.05）。Fe2O3、CeO2作为Y-TZP的内着色剂,粉体大多成球形。结论 CeO2作为口腔修复用Y-TZP的着色剂,对造粒粉料的粒径分布以及成球性能影响不大;Fe2O3作为着色剂进行内着色对颗粒的粒径产生一定的影响。     

Y-TZP口腔修复材料的低温老化及抗低温老化的相关研究

综合国内外相关研究,了解氧化钇稳定的四方氧化锆多晶陶瓷(Y-TZP)口腔修复材料的低温老化现象,探讨抗Y-TZP修复陶瓷低温老化的方法,展望抗低温老化Y-TZP陶瓷在口腔临床中的应用.抗Y-TZP低温老化的方法包括:稳定剂类型和含量的选择、加工工艺的改善、适宜的表面处理、合成复合陶瓷等,其中Y-TZP/Al2O3复合陶瓷对Y-TZP的低温老化有较大程度的缓解作用,且能明显改善Y-TZP的机械性能,是一种在口腔临床应用中具有发展前景的氧化锆基陶瓷材料.     

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。     

共沸蒸馏法制备牙科氧化锆纳米晶微粉的研究

目的 :探讨用于制备高性能氧化锆牙科陶瓷的氧化锆纳米晶微粉的方法与条件。方法 :采用非均相共沸蒸馏法以正丁醇为夹带剂对水合氢氧化锆凝胶进行脱水 ,比较在减压、常压条件下和直接用乙醇洗脱水所制备的氧化锆粉体的性能。结果 :水合氢氧化锆凝胶经干燥煅烧后 ,成功制成了氧化锆纳米晶微粉。直接用乙醇洗脱水 ,粉体的dBET约为 2 5nm ;在减压共沸蒸馏的条件下 ,粉体的dBET约为 2 2nm ;在常压共沸蒸馏的条件下 ,粉体的dBET约为 17nm。 3种粉体模压成型 ,无压烧结得到陶瓷的弯曲强度分别为 660、710、64 0MPa ,断裂韧性分别为 4.3 4、4.77、4.2 4MPa·m1/ 2 。结论 :用常压共沸蒸馏法能有效地克服硬团聚的形成 ,制得粒径较小、烧结活性较高的氧化锆纳米晶微粉     

氧化钇稳定的四方多晶氧化锆的表面处理工艺初探

3mol％氧化钇稳定的四方多晶氧化锆(3mol％yttria stabilize tetragonal zirconia polycrystal，3Y-TZP)因具有高断裂韧性，临床应用于预成桩和全瓷基底冠的制作，其表面致密、稳定，硅含量极少。我们用二氧化硅对3Y-TZP进行表面处理，以提高3Y-TZP表面硅含量，旨在通过硅烷偶联剂提高其对树脂的粘接力。     

改良液式冲蚀对3Y-TZP氧化锆基底与饰面瓷结合强度的影响

目的:探讨采用改良液式冲蚀方式对3Y-TZP氧化锆基底表面进行冲蚀后,对其与饰面瓷间结合强度的影响.方法:制作[8 mm×8 mm×3 mm(±0.02)]氧化锆试件块174个,根据不同尺寸的刚玉磨粒、不同的喷砂压强、不同的喷砂时间,采用传统喷砂方式进行分组处理(实验组),在氧化锆处理面上饰面瓷.表面未做处理的氧化锆试件直接上饰面瓷作为对照组,应用电子万能测力计检测各组试件与饰面瓷间的最大剪切力,计算剪切强度.分别用传统干式喷砂、改良液式冲蚀方式在相同条件下(150 μm,0.6 MPa,30 s)处理氧化锆试件块,用扫描电镜下观察处理面,再上饰面瓷,计算剪切强度,与对照组进行组间比较.采用SPSS17.0软件包对数据进行统计学分析.结果:采用传统干式喷砂方式,在0.4 MPa压强作用下,以110 μm A12O3喷砂粉喷砂20 s时,氧化锆与饰面瓷之间的剪切强度最大,显著大于对照组(P＜0.05);改良液式冲蚀组饰面瓷的结合强度显著大于传统干式喷砂处理组及对照组(P＜0.01).扫描电镜下可见,采用改良液式冲蚀的试件表面呈现均匀的粗糙面:采用传统干式喷砂处理的试件表面呈现不均匀的粗糙面,部分位置可见微裂纹.结论:对3Y-TZP氧化锆表面喷砂,能够增强其与饰面瓷间的结合强度;改良液式冲蚀比传统干式喷砂更适用于3Y-TZP氧化锆的表面处理.     

SEM observations of porcelain Y-TZP interface

ObjectivesThe metastability of the tetragonal phase of yttria tetragonal zirconia polycrystalline (Y-TZP) ceramics is a cause for concern in dental crown and bridge applications. One specific problematic area is the nature of the interface between the veneering porcelain and the Y-TZP framework and whether the associated preparation procedures and reactions result in a reduction of the stability of the zirconia.MethodsTo investigate this aspect, high-resolution SEM observations were made of polished and etched (HF content gel) cross-sections of the interface area. Dry and moist veneering porcelain powders were built up on the zirconia base.ResultsIn some instances the zirconia grains at the interface appear to show multiplicity of subgrain faceting whereas in other instances they do not. The latter indicate destabilisation of the tetragonal phase occurs and in addition that the porcelain veneering material wets and some dissolution of the Y-TZP occurs.SignificanceThese results and their relevance to the long-term stability of the interface adhesion to the veneering porcelain as well as possible tetragonal to monoclinic crystal transformations at the interface are discussed.     

Current status of zirconia restoration

During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia restoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed.Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain.There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is currently one of the most reliable bonding systems for zirconia. Adhesive treatments could be applied to luting the restorations and fabricating hybrid-structured FDPs. Full-contour zirconia FDPs caused concern about the wear of antagonist enamel, because the hardness of Y-TZP was over double that of porcelain. However, this review demonstrates that highly polished zirconia yielded lower antagonist wear compared with porcelains. Polishing of zirconia is possible, but glazing is not recommended for the surface finish of zirconia.Clinical data since 2010 are included in this review. The zirconia frameworks rarely got damaged in many cases and complications often occurred in the veneering ceramic materials. Further clinical studies with larger sample sizes and longer follow-up periods are required to investigate the possible influencing factors of technical failures.     

钇稳定氧化锆基底材料与饰面瓷结合性能的实验研究

目的考察国产氧化钇稳定四方晶体氧化锆（3Y-TZP）与4种氧化锆专用饰面瓷界面的结合性能。方法粉浆涂塑方法分别将VITA VM9、SHOFU VINTAGE ZR、IPS e.max Ceram、Cercon ceram kiss 4种氧化锆专用饰面瓷烧结在15 mm×5 mm×5 mm的3Y-TZP核瓷试件上,另外制作相同尺寸镍铬合金烤瓷试件作为对照,测试界面剪切强度。制作氧化锆基底与饰面瓷双层瓷试件,扫描电镜（SEM）观察结合界面微观形貌;能谱分析（EDS）检测界面元素分布。结果氧化锆与VITA VM9、SHOFU VINTAGE ZR、IPS e.max Ceram、Cercon ceram kiss 4种氧化锆专用饰面瓷的剪切强度分别为（18.83±1.77）MPa、（23.83±7.05）MPa、（17.87±2.30）MPa、（22.26±7.45）MPa,各组与金属烤瓷对照组比较,差异均无统计学意义（P＞0.05）。各3Y-TZP烤瓷组试件破坏模式以界面破坏为主。扫描电镜观察氧化锆和饰面瓷结合界面结合紧密;能谱分析结果显示二者存在化学元素渗透。结论国产3Y-TZP与饰面瓷材料界面结合良好,可以满足临床需要。     

Influence of thermal expansion mismatch and fatigue loading on phase changes in porcelain veneered Y-TZP zirconia discs

There is a rapidly growing interest for the use of Y-TZP zirconia as core material in veneered all-ceramic prostheses. It was hypothesized that a mismatch in coefficient of thermal expansion between the veneering porcelain and the Y-TZP zirconia core of these prostheses causes transformation of the tetragonal to the monoclinic structure in Y-TZP zirconia at the interface boundary when exposed to fatigue loading, resulting in fracture at the interface boundary. Y-TZP zirconia discs were veneered with three porcelains differing in coefficient of thermal expansion. Finite element analysis was used to investigate the stress distribution in the bi-layered discs because of the mismatch in thermal expansion. Two of these three groups were fatigued with the veneering ceramic in tension. X-ray diffraction was used to measure the intensity of monoclinic and tetragonal zirconia phase present at the zirconia core surface after sintering, airborne abrasion, veneering, and fatigue loading. It was found that the sintered tetragonal structure was converted to monoclinic up to a depth of 27 mum after airborne abrasion, and reversed back to tetragonal after porcelain veneering with porcelain. Fatigue loading of veneered discs did not, even with the highest possible thermal mismatch stress, cause any conversion from tetragonal to monoclinic phase.     

Making yttria-stabilized tetragonal zirconia translucent

ObjectiveThe aim of this study was to provide a design guideline for developing tetragonal yttria-stabilized zirconia with improved translucency.MethodsThe translucency, the in-line transmission in particular, of 3 mol.% yttria-stabilized tetragonal zirconia (3Y-TZP) has been examined using the Rayleigh scattering model. The theory predicts that the in-line transmission of 3Y-TZP can be related to its thickness with grain size and birefringence the governing parameters. To achieve a threshold value of translucency, the critical grain size of 3Y-TZP was predicted for various thicknesses (0.3–2.0 mm). The threshold value was defined by a measured average in-line transmission value of a suite of dental porcelains with a common thickness of 1 mm. Our theoretical predictions were calibrated with one of the very few experimental data available in the literature.ResultsFor a dense, high-purity zirconia, its in-line transmission increased with decreasing grain size and thickness. To achieve a translucency similar to that of dental porcelains, a nanocyrstalline 3Y-TZP structure was necessitated, due primarily to its large birefringence and high refractive index. Such a grain size dependence became more pronounced as the 3Y-TZP thickness increased. For example, at a thickness of 1.3 mm, the mean grain size of a translucent 3Y-TZP should be 82 nm. At 1.5 mm and 2 mm thicknesses, the mean grain size needed to be 77 nm and 70 nm, respectively.SignificanceA promising future for zirconia restorations, with combined translucency and mechanical properties, can be realized by reducing its grain size.     

稀土氧化物着色牙色四方多晶氧化锆陶瓷的烧结性能

目的 探讨添加微量稀土氧化物对以稀土氧化物作为着色剂制备的与天然牙颜色匹配的牙色四方多晶氧化锆陶瓷的烧结性能的影响。方法 采用内着色法制备6组与天然牙色匹配的四方多晶氧化锆陶瓷,通过阿基米德定律测试其烧结致密性,通过扫描电镜观察其显微结构,X射线衍射测试其相变特征。结果 6组与天然牙色匹配的四方多晶氧化锆陶瓷的相对密度达到98%;电镜观察可见氧化锆的晶粒完整、晶界清楚、晶粒大小均匀,100～300 nm,未见异常生长的晶粒,晶界处未见到第二相的杂质相;XRD图谱显示,6种牙色四方多晶氧化锆陶瓷的晶相组成均以四方相氧化锆的特征峰为主,未见明显的杂质峰。结论 微量稀土氧化物的添加对以稀土氧化物作为着色剂制备的与天然牙颜色匹配的牙色四方多晶氧化锆陶瓷的烧结性能的影响较小,最终烧结体的主晶相仍以四方相为主。