Improved performances of lithium disilicate glass-ceramics by seed induced crystallization

Self-reinforced lithium disilicate(Li_(2)Si_(2)O_(5),LD)glass-ceramics were hot pressing sintered by introducing 5 wt%Li_(2)Si_(2)O_(5)crystal seeds into two different glass compositions of SiO_(2)-Li_(2)O-P2O_(5)-ZrO_(2)-Al_(2)O_(3)-K_(2)O-La_(2)O_(3)(7C LD)and SiO_(2)-Li_(2)O-K_(2)O-La_(2)O_(3)(4C LD).The results show that the seeds play an important role in the crystallization inducement,and microstructural and property improvement of the glass,especially for the glass powder without the nucleating agent of P_(2)O_(5).The microstructure features a wider bimodal grain size distribution with large rod-like crystals epitaxially grown along the seeds and small crystals nucleated from the glass powder itself,contributing to the improvement of the performance especially the fracture toughness.The specimen of 4C LD glass with the addition of 5 wt%Li_(2)Si_(2)O_(5) seeds exhibited the best comprehensive properties with a good flexural strength(396±7 MPa),improved fracture toughness(3.31±0.19 MPa·m^(1/2)),and comparable translucency as IPS e.max.This research provides a new idea and method for the improvement of the fracture toughness of lithium disilicate glass-ceramics without affecting its aesthetic appearance,and lays the foundation for its clinical applications.

Glass-Ceramics with High Strength and High Transmittance Obtained by Multi-Factor Controlling

The presence of Li_(2)Si_(2)O_(5) and LiAlSi_(4)O_(10) could effectively improve the elastic modulus and transmittance of lithium disilicate(LD)glass-ceramics.Through synergistically modulation of the crystal content and grain size,we obtained high strength and high transmittance of LD glass-ceramics.The optimal sample had a high transmittance of 90.3%,the hardness was 7.72 GPa,the fracture toughness was 1.07 MPa·m^(1/2),and the elastic modulus was 103.1 GPa.

Densification of Lithium Disilicate under High Pressure Investigated by XPS

The aim of this work was to investigate by X-ray photoelectron spectroscopy the effect of high pressure on the chemical environments of Si 2p, O 1s and Li 1s in lithium disilicate glass ceramic with stoichiometric composition Li2O·2SiO2 (LS2). A group of samples was processed at 2.5 GPa, 4 GPa and 7.7 GPa at room temperature and a second group was crystallized under high pressure and high temperature. Large shifts of the binding energy toward higher energies were observed in the X-ray photoelectron spectroscopy spectra for samples of the first group after densification at 2.5 and 4 GPa. For samples processed at 7.7 Gpa, the major component of the binding energy for the Si 2p environment remained practically unchanged compared to the pristine sample but new components, with smaller intensities, appeared in the spectra, indicating the existence of distinct Q-species induced by high pressure. This behavior may be related to changes in the number of bridged and non-bridged oxygen atoms in the glass structure. The results for the second group of samples, crystallized under high pressure, showed evidences of three binding energies for the O atoms, one of them related to non-bridged and two of them to bridged O atoms.

The Crystallization and Fracture Toughness of Transparent Glass-ceramics with Various Al_(2)O_(3) Additions for Mobile Devices

Li_(2)O-Al_(2)O_(3)-SiO_(2)(LAS)glass-ceramics were prepared by a melting method.Effects of different Al_(2)O_(3)content on the structure,crystallization,transmittance and fracture toughness of LAS glassceramics were investigated by means of XRD,FESEM and other methods as well.The results showed that the glass transition temperature and crystallization temperature of samples increased as the content of Al_(2)O_(3)increased from 4.1 wt%to 13.1 wt%,which restrained the precipitation of lithium disilicate crystals.The main crystalline phase of glass-ceramics transformed from lithium disilicate and petalite to silicon dioxide,which reduced the fracture toughness of glass-ceramics.When the Al_(2)O_(3)content was 7.1 wt%,the specimen had outstanding transmittance and fracture toughness.The transmittance was 90.32%.The fracture toughness was 1.13 MPa•m^(1/2).Compared with high-alumina glass,the fracture toughness of the glass-ceramic was greatly improved,and it could be used as a new type of protective material for mobile devices.

短冠磨牙远中邻牙合缺损髓腔固位冠修复的三维有限元分析

背景:对于牙冠高度正常的牙齿,不同髓腔固位深度及不同修复材料的髓腔固位冠修复对牙体组织应力大小及抗折性有影响,对于短冠磨牙缺损利用髓腔修复的研究多集中在临床观察及体外抗折性实验。目的:建立根管治疗后短冠磨牙髓腔固位冠修复的三维有限元模型,分析不同髓腔固位深度及修复材料的修复体对牙本质等效应力分布及大小的影响。方法:在建立完整短冠下颌第一磨牙模型的基础上,建立不同髓腔固位深度(h=2,3,4 mm)、不同修复材料(氧化锆、二硅酸锂)的髓腔固位冠修复短冠磨牙远中邻牙合缺损的三维有限元模型,采用斜向加载,观察等效应力分布情况,计算牙本质等效应力峰值及近中髓室壁近髓室底等效应力平均值。结果与结论:①等效应力集中部位:完整短冠磨牙及修复后各模型应力主要集中在近中根近中颈部及近中根舌侧颈部,修复后各模型垫底层对应的近中髓室壁近髓室底处均有应力集中区,其中以髓腔固位深度4 mm组应力集中明显;②在相同修复材料下,修复后各模型牙本质等效应力峰值均以髓腔固位深度3 mm组最小,近中髓室壁近髓室底处牙本质等效应力平均值均为髓腔固位深度3 mm组最小;③在相同固位深度下,氧化锆组及二硅酸锂组牙本质等效应力峰值及近中髓室壁近髓室底处牙本质等效应力平均值均相差不大;④结果表明,在此次实验条件下,短冠磨牙缺损采用髓腔固位冠修复时固位深度为3 mm更有利于保护剩余牙体组织,修复材料选择氧化锆或二硅酸锂对牙本质应力影响区别不大。

1374例椅旁CAD/CAM全瓷修复体的类型及颜色调查

目的:分析椅旁CAD/CAM全瓷修复体的类型及使用的全瓷材料的颜色区间,为指导临床椅旁全瓷修复的应用及材料的颜色选择提供参考。方法:收集整理2021年1月—2021年12月上海交通大学医学院附属第九人民医院口腔修复科使用椅旁CAD/CAM切削IPS e.max CAD材料的修复体相关数据。对修复体的数量、类型和全瓷材料的颜色分布进行调查,分析修复体的类型和材料的颜色分布频率。结果:共纳入1374枚修复体,其中,冠修复体最多,624例,占总修复体的45.41%;贴面516例,占37.55%;嵌体219例,占15.94%;固定桥均为粘接桥,数量最少,仅15例,占1.09%。修复材料的选择方面,低透(LT)瓷块的使用频率显著高于其他透明度的瓷块;A色系为使用频率最高的颜色。贴面最常选用的瓷块为LTA2和LTA1;嵌体使用最多的为LTA3;冠使用最多的为LTA2和LTA3;固定桥使用的瓷块均为LT色系,A3色占多数。结论:使用IPS e.max CAD材料制作的椅旁CAD/CAM全瓷修复体已广泛用于临床,修复体类型包括贴面、嵌体、冠和粘接固定桥。临床最常用的IPS e.max CAD瓷块为LTA2、LTA3、LTA1,这对基层医院的临床修复决策及瓷块储备具有一定的指导意义。

锂基玻璃陶瓷核瓷瓷块种类和厚度对深色基牙遮色能力的研究

目的:研究不同锂基玻璃陶瓷核瓷种类和厚度对深色基牙的遮色能力,为临床医生和技师选择修复材料提出指导意见。方法:将IPS E.max Press低透LT A1色铸瓷块(LT)、中度不透MO1色铸瓷块(MO)和高度不透HO1色铸瓷块(HO)制作成厚度为0.4 mm、0.5 mm、0.6 mm和0.8 mm的瓷片试件,分别粘接在金合金、镍铬合金、ND6色和ND8色树脂底物上,用以模拟金属桩核及深色基牙,以A2色作为基线,使用数字比色仪测量各组Lab值,并与基线相比较计算色差值ΔE。结果:无论是LT、MO还是HO瓷块,随着瓷片厚度的增加,其在不同颜色底物上的色差值均显著减小(除金合金外);当瓷层厚度大于等于0.5 mm时,对于各种底物,HO组的色差值均显著小于MO组和LT组;当瓷层厚度小于等于0.6 mm时,底色偏黄的基牙使用遮色核瓷后效果优于底色偏灰黑的基牙;当瓷层厚度达到0.8 mm时,各类核瓷对各种颜色底物的遮色效果均较好且差异无统计学意义。结论:瓷层厚度、核瓷种类以及基牙底色均会影响最终修复体的颜色,对于深色基牙,使用高度不透的核瓷瓷块和/或增加瓷层厚度均可提高遮色效果。

二硅酸锂基玻璃陶瓷单端树脂粘接桥修复个别前牙缺失的临床应用

目的探讨二硅酸锂基玻璃陶瓷单端树脂粘接桥修复个别前牙缺失的临床效果,为个别前牙缺失修复方式的选择提供参考。方法本研究已通过单位伦理委员会审查批准,并获得患者知情同意。选取42例单颌前牙缺失数量在两颗内的患者,采用二硅酸锂基玻璃陶瓷单端树脂粘接桥修复,修复后6个月、1年、2年、3年进行随访,评价美学、功能修复效果及牙周健康状况,并采用视觉模拟评分量表(VAS)调查患者的满意度。结果观察期间,42例二硅酸锂基玻璃陶瓷单端树脂粘接桥修复的患者中有1例3个月内连接体发生断裂,1例2年内发生脱粘;美学修复效果的等级均评定为A级;修复后牙周健康状况良好,基牙及桥体下的软硬组织无临床吸收现象,评价指标均为A级;患者总满意率为100%。结论对于个别前牙缺失,二硅酸锂基玻璃陶瓷单端树脂粘接桥可达到微创、固位牢靠、美观舒适和生物相容性好的修复效果,患者满意度高,在临床中可以考虑作为一种理想的修复方式。

二硅酸锂微晶玻璃专利技术发展态势研究

为探究二硅酸锂微晶玻璃全球技术发展态势、区域分布、技术布局和热点前沿,依托IncoPat专利信息检索与分析系统,借助Excel等工具,对全球1325件二硅酸锂微晶玻璃专利进行多维度揭示与分析。结果表明:全球二硅酸锂微晶玻璃技术研发总体呈增长态势;美国、中国、列支敦士登和日本是全球四大技术来源国;中国、美国、日本和欧洲专利局是全球重要目标市场国家和地区;列支敦士登义获嘉伟瓦登特公司、美国康宁公司和日本株式会社小原是全球重要创新主体;中国有三家企业入榜全球前十创新主体;二硅酸锂微晶玻璃的制备、辅助工艺以及二硅酸锂微晶玻璃牙科领域的应用研究是研发热点。研究结果可为我国二硅酸锂微晶玻璃技术创新、产业规划及专利布局提供重要借鉴。

研磨和抛光对二硅酸锂玻璃陶瓷动态磨损行为影响的研究

目的:研究模拟口腔环境下研磨和抛光对二硅酸锂玻璃陶瓷动态磨损行为的影响,为口腔临床操作提供参考。方法:制备直径3 mm、长8 mm的二硅酸锂玻璃陶瓷上试件和直径20 mm、厚4 mm的二硅酸锂玻璃陶瓷下试件各16个,将上、下试件随机分为两组,一组打磨至600目作为研磨组,另一组打磨至2000目作为抛光组,每组8个样本,在摩擦磨损试验机将上、下试件组成一对摩擦副,在人工唾液、室温环境、20 N载荷、转速100 r/min、回转半径2.5 mm、匀速圆周运动的条件下进行50万次循环磨损实验。在整个磨损周期中选取10个循环节点,用三维形貌仪测量每个节点圆盘试件的磨损高度损失量并绘制相应磨损曲线,再利用扫描电镜观察相应磨损阶段对应的磨损面微观形貌。结果:整个磨损过程中,各节点测量值显示研磨组二硅酸锂玻璃陶瓷的磨损量均大于抛光组二硅酸锂玻璃陶瓷的磨损量(P<0.05);两组二硅酸锂玻璃陶瓷的磨损曲线均呈现“跑合期”和“稳定磨损期”两个磨损阶段,研磨组的“跑合期”较抛光组的“跑合期”长,进入“稳定磨损期”的时间比抛光组迟。两组试件的微观形貌也呈现出与磨损曲线对应的两阶段规律。结论:在模拟口腔环境下,研磨组二硅酸锂玻璃陶瓷的磨损量显著高于抛光组,提示临床应重视戴牙时修复体的充分抛光以降低磨损、延长修复体使用寿命。

基于3shape数字化扫描制作的临时和长期修复体在拔牙后即刻种植中的应用

目的:探讨基于3shape数字化扫描制作的临时和长期修复体在拔牙后即刻种植中的临床应用效果。方法:采用前瞻性自身对照实验设计,选取我院口腔科2020年6月—2021年3月期间参与即刻种植的60例患者作为研究对象,并分为对照组和试验组,每组各30例,对照组采用传统加工方法制作螺丝固位树脂临时修复体,试验组采用3shape Trios系统辅助制作系统加工制作螺丝固位二硅酸锂修复体,对比两组患者的短期疗效、满意度情况和远期效果。结果:试验组的修复体精准度高于对照组,且WES评分低于对照组(P<0.05);试验组的临床修复时间低于对照组,且平均VAS满意度评分高于对照组(P<0.05);试验组在边缘适应性、解剖外形方面达到优秀的例数均多于对照组(P<0.05)。结论:基于3shape数字化扫描的二硅酸锂修复体在即刻种植中表现优越,具有高修复精准度、短修复时间及高患者满意度。

三种CAD/CAM全瓷材料[牙合]贴面抗折能力实验研究

目的:探讨三种CAD/CAM(Computer-aided design/Computer-aided manufacturing)全瓷材料全解剖式[牙合]贴面的抗折能力,为临床应用提供参考。方法:扫描离体下颌右侧第一磨牙建立数字模型,在数字模型上进行[牙合]贴面数字备牙,共四个厚度,分别为1.0 mm、1.5 mm、2.0 mm、2.5 mm,选取二硅酸锂玻璃陶瓷瓷块2种(IPS e.max CAD瓷、VITA SUPRINITY瓷)和树脂基陶瓷瓷块1种(Lava Ultimate优韧瓷),数字设计和数字切削制作相应厚度全瓷[牙合]贴面,每种瓷块每个厚度10例,共获120例[牙合]贴面。将[牙合]贴面加压粘接到3D打印硬质树脂代型上,循环加载后,使用万能材料试验机进行垂直加载试验,记录[牙合]贴面断裂载荷,观察失效模式。使用SPSS 22.0软件对数据进行统计分析。结果:断裂载荷结果显示,在厚度为1.0 mm、1.5 mm、2.0 mm时三种材料间断裂载荷比较差异有统计学意义(P<0.05),厚度为2.5 mm时,两种玻璃陶瓷之间差异无统计学意义(P>0.05),而玻璃陶瓷和树脂基陶瓷之间断裂载荷比较差异有统计学意义(P<0.05)。两种玻璃陶瓷随着厚度增加,断裂载荷也随之增大(P<0.05);树脂基陶瓷厚度为1.0 mm、1.5 mm、2.0 mm时的断裂载荷也随着厚度增大(P<0.05)。三种[牙合]贴面的断裂模式均表现为裂纹,破碎和折裂。结论:三种CAD/CAM全瓷材料全解剖式[牙合]贴面抗折能力均能满足后牙[牙合]面缺损修复的需要,树脂基陶瓷操作步骤相对简单;临床上尽量选择较薄的贴面进行修复,以利于颞下颌关节的适应。

基于静电纺丝技术的二硅酸锂微晶玻璃纤维制备及其可纺性研究

采用溶胶-凝胶法结合静电纺丝技术构建锂硅凝胶纤维,对其进行后续晶化,得到二硅酸锂(Li_(2)Si_(2)O_(5))微晶玻璃纤维.研究纺丝助剂聚乙烯醇(PVA)含量及陈化时间对前驱体溶液黏度、可纺性及纤维形貌的影响规律,探讨了凝胶纤维的形成机理.结果表明,PVA含量越多、陈化时间越长,黏度越大,纤维可纺性增加,但PVA含量过高和陈化时间过长,都会使得电场力无法克服表面张力从而无法形成均匀的无珠状纤维.当PVA含量10 wt%、陈化时间48 h,能够得到均匀且几乎无珠状的凝胶纤维;正硅酸乙酯在酸催化作用下的脱水脱醇,生成的单体硅酸又在溶液中相互缩合形成聚合度高的硅酸,与聚乙烯醇碳链发生缩合形成复合凝胶纤维;在880℃经2 h晶化处理后得到平均直径为0.80μm的Li_(2)Si_(2)O_(5)微晶玻璃纤维,为后续制备纤维增韧Li_(2)Si_(2)O_(5)微晶玻璃复合材料奠定了基础.

前牙全瓷悬臂式粘接桥的应用及研究策略

背景:全瓷悬臂式粘接桥,其从治疗时间、侵入性、美观性及价格等多方面体现出来的优势,使其成为目前临床口腔前牙美学修复中热门的话题。目的:总结归纳全瓷悬臂式粘接桥临床技术难点上的解决策略以及在前牙应用的优势,并介绍目前现有的全瓷悬臂式粘接桥的临床随访方法,以期在前牙牙列部分缺损的美学修复领域提供临床及科研指导。方法:由第一作者检索Web of Science、PubMed、中国知网和万方数据库检索1955-2021年发表的文献,英文检索词为“Denture,Partial,Fixed,Resin-Bonded,Resin Bonded Bridge,Maryland Bridge,Adhesive bridge,single-retainer,all-ceramic”;中文检索词为“粘接桥、马里兰桥、粘接固定桥、全瓷、悬臂式、单端”,经筛选后纳入60篇文献进行综述分析。结果与结论:①通过选择氧化锆瓷材料进行有效的表面预处理能较好地预防折裂发生;设计近缺隙侧盒状洞形及舌隆突处钉洞固位形为现在专家共识之一,能有效减少粘接桥脱落的发生,提高远期存留效果;在满足适应证的条件下,全瓷悬臂式粘接桥的龋坏牙周病等并发症发生率较低,美学效果好,存留时间长,可作为永久性修复体使用。②对于临床研究,除统计基本的存留率成功率外,推荐同步使用口腔健康相关生活质量表、满意度问卷调查以及美国公共卫生协会修复体评价标准等进行评估,以此全面评估修复效果。③但值得注意的是,不同研究对存留率和成功率的定义不同,对数据统计造成一定的偏差,因此全瓷悬臂式粘接桥的实际临床效果还值得进一步探究。

超薄玻璃陶瓷贴面的光学性能及光照方案对树脂水门汀固化程度的影响

目的:研究超薄瓷贴面透明度、颜色和光照方案对树脂水门汀聚合性能的影响。方法:厚度为0.4 mm的二硅酸锂玻璃陶瓷试件按照透明度(HT,LT),瓷块颜色(A2,BL2)分为4组(n=5)。便携式辐射计测量光固化灯低光强模式和高光强模式下透过各组瓷试件的光照强度衰减率。光固化树脂水门汀被各组瓷试件遮盖后分别采用4种不同的光照方案(高光强40 s,低光强40 s,高光强20 s,低光强20 s)光照固化,制备树脂水门汀试件。傅里叶红外光谱扫描仪和显微硬度仪测量各组树脂水门汀试件的转化率和维氏显微硬度。结果:超薄瓷贴面的透明度(P<0.05)和光照方案(P<0.001)显著影响树脂水门汀的固化性能,其颜色则无显著影响(P>0.05)。HT BL2组瓷试件采用高光照40 s光照方案时,树脂水门汀的转化率(53.04±2.13)%和维氏显微硬度(311.18±29.29)MPa的数值最高。LT A2组瓷试件采用低光照20s光照方案时,树脂水门汀的转化率(42.52±1.97)%和维氏显微硬度(225.27±27.49)MPa的数值最低。结论:厚度为0.4 mm的二硅酸锂玻璃陶瓷的透明度和光照方案均影响树脂水门汀的固化性能,增加光照强度和照射时间可以提高树脂水门汀的固化性能。

Hardness of resin cement cured under different thickness of lithium disilicate-based ceramic

Background The lithium disilicate-based ceramic is a newly developed all-ceramic material, which is lithium disilicate-based and could be used for fabricating almost all kinds of restorations. The extent of light attenuation by ceramic material was material-dependent. Ceramic materials with different crystal composition or crystalline content would exhibit distinct light-absorbing characteristics. The aim of this study was to analyze the influence of ceramic thickness and light-curing time on the polymerization of a dual-curing resin luting material with a lithium disilicate-based ceramic. Methods A lithium disilicate-based ceramic was used in this study. The light attenuation caused by ceramic with different thickness was determined using a spectral radiometer. The commercial dual-cured resin cement was light-cured directly or through ceramic discs with different thickness （1, 2 and 3 mm, respectively） for different times （10, 20, 30, 40, 50 and 60 seconds, respectively）. The polymerization efficiency of resin cement was expressed in terms as Vickers hardness （VHN） measured after 24 hours storage. Two-way analysis of variance （ANOVA） and Tukey＇s HSD tests were used to determine differences. Results Intensity of polymerizing light transmitted through ceramic discs was reduced from 584 mW/cm2 to about 216 mW/cm2, 80 mW/cm2 and 52 mW/cm2 at thicknesses of 1 mm, 2 mm and 3 mm, respectively. Resin cement specimens self-cured alone showed significantly lower hardness values. When resin cement was light-cured through ceramic discs with a thickness of 1 mm, 2 mm and 3 mm, no further increasing in hardness values was observed when light-curing time was more than 30 seconds, 40 seconds and 60 seconds, respectively. Conclusions Within the limitation of the present study, ceramic thickness and light-curing time had remarkable influence on the polymerization of dual-cured resin cement. When resin cement is light-cured beneath a lithium disilicate ceramic with different thickness, prolonging light-curing time accordingly may still be necessary to insure complete polymerization.

Er-YAG激光对不同瓷贴面拆除效率的体外评价

目的:比较Er:YAG激光拆除不同厚度和透明度的二硅酸锂玻璃陶瓷贴面的时间,观察其对贴面和牙面表面形貌的影响。方法:对12颗离体上颌第一前磨牙的颊面进行贴面预备,通过计算机辅助设计与制作系统完成12个全瓷(IPS e.max CAD二硅酸锂玻璃陶瓷材料)贴面制作,颜色均为A2色。依据材料和厚度不同将12个贴面分成4组,即e.max HT 0.5 mm组、e.max HT 1.0 mm组、e.max LT 0.5 mm组和e.max LT 1.0 mm组。采用树脂水门汀将贴面与对应的预备体粘接,室温下利用生理盐水进行样本储存。7天后通过Er:YAG激光拆除各组贴面,记录所需时间。将拆除后的离体牙、e.max HT 0.5 mm贴面组和e.max LT 0.5 mm贴面组进行扫描电镜(scanning electron microscopy,SEM)观察,检测拆除后的表面形貌改变。采用SPSS 19.0软件包对数据进行统计学分析。结果:1.0 mm厚的全瓷贴面较0.5 mm厚的拆除时间长,e.max LT 0.5 mm组拆除时间长于e.max HT 0.5 mm组,e.max LT 1.0 mm组拆除时间长于e.max HT 1.0 mm组,均有统计学差异。经Er:YAG激光拆除的全瓷贴面SEM未发现明显裂缝裂纹、“凹坑状”破坏等;牙面SEM见粘接剂覆盖,未发现裂纹、牙釉质熔融现象。结论:Er:YAG激光可成功拆除二硅酸锂玻璃陶瓷贴面;材料类型、厚度影响其拆除时间,e.max LT贴面透光率较低则拆除时间较长,并且贴面越厚所需的拆除时间越长。Er:YAG激光能量不会导致陶瓷和牙体组织的表面形貌受损。

Optimized sintering and mechanical properties of Y-TZP ceramics for dental restorations by adding lithium disilicate glass ceramics

The novel dental ceramics can be fabricated at lower temperatures when sol-gel derived lithium disilicate glass ceramics(LDGC)was used as an additive for yttria stabilized tetragonal zirconia polycrystalline(Y-TZP)ceramics.The effect of LDGC on the sintering,mechanical,and translucent properties of Y-TZP ceramics was investigated in the present study.The results showed that the LDGC additive effectively improved the densification of Y-TZP at 1100℃,which was much lower than the sintering temperature for pure Y-TZP.When sintered at 1100℃,the Y-TZP with 1 wt%LDGC reached a relative density of 95.45%,and prossessed a flexural strength of 482.4 MPa and a fracture toughness of 5.94 MPa-m12.Moreover,its translucency was also improved.While,the addition of LDGC could result in an escape of yttrium atoms from the grain lattice of zirconia,which induced the tetragonal-monoclinic transformation of zirconia and abnormal growth of monoclinic grains.The escaped yttrium atoms diffused into the intergranular glass phase.The results indicated that the novel Y-TZP-LDGC ceramics has a great potential to be used for all-ceramic restorations.

不同厚度二硅酸锂玻璃陶瓷[牙合]贴面抗折能力实验研究

目的:探讨不同厚度二硅酸锂玻璃陶瓷[牙合]贴面抗折能力,为全瓷[牙合]贴面咬合重建的可行性提供理论支持。方法:采用完整离体下颌右侧第一磨牙,进行数字扫描,制取数字模型。在数字模型上进行[牙合]贴面数字备牙,共四个厚度,分别为1.0 mm,1.5 mm,2.0 mm,2.5 mm。根据设计厚度,设计数字[牙合]贴面,使用CAD/CAM全瓷切削设备制作二硅酸锂玻璃陶瓷[牙合]贴面,每个厚度8例,共32例。3D打印硬质树脂备牙代型,将玻璃陶瓷[牙合]贴面粘接到硬质树脂代型上,选取[牙合]贴面表面近舌尖,远舌尖,远颊尖3点形成加载平面,使用万能材料实验机进行垂直加压试验,直至贴面失效,记录[牙合]贴面断裂力值,观察失效模式。使用SPSS 22.0软件进行统计分析。结果:垂直加压试验显示4个厚度[牙合]贴面平均断裂力值分别为(2309.13±127.66)N,(3158.38±154.72)N,(6170.00±208.50)N,(5306.25±174.81)N。[牙合]贴面的失效模式表现为裂纹,破碎和全层折裂。结论:特定厚度二硅酸锂玻璃陶瓷[牙合]贴面具有足够的抗折能力,能够满足后牙区咬合重建的需要。

Air-stable Li_(3.12)P_(0.94)Bi_(0.06)S_(3.91)I_(0.18)solid-state electrolyte with high ionic conductivity and lithium anode compatibility toward high-performance all-solid-state lithium metal batteries

Sulfide solid-state electrolytes(SSEs)with superior ionic conductivity and processability are highly promising candidates for constructing all-solid-state lithium metal batteries(ASSLMBs).However,their practical applications are limited by their intrinsic air instability and serious interfacial incompatibility.Herein,a novel glass-ceramic electrolyte Li_(3.12)P_(0.94)Bi_(0.06)S_(3.91)I_(0.18)was synthesized by co-doping Li_(3)PS_(4)with Bi and I for high-performance ASSLMBs.Owing to the strong Bi-S bonds that are thermodynamically stable to water,increased unit cell volume and Li+concentration caused by P5+substitution with Bi3+,and the in situ formed robust solid electrolyte interphase layer LiI at lithium surface,the as-prepared Li_(3.12)P_(0.94)Bi_(0.06)S_(3.91)I_(0.18)SSE achieved excellent air stability with a H2S concentration of only 0.205 cm^(3)g^(-1)(after 300 min of air exposure),outperform-ing Li_(3)PS_(4)(0.632 cm^(3)g^(-1))and the most reported sulfide SSEs,together with high ionic conductivity of 4.05 mS cm^(-1).Furthermore,the Li_(3.12)P_(0.94)Bi_(0.06)S_(3.91)I_(0.18)effectively improved lithium metal stability.With this SSE,an ultralong cyclabil-ity of 700 h at 0.1 mA cm^(-2)was realized in a lithium symmetrical cell.Moreover,the Li_(3.12)P_(0.94)Bi_(0.06)S_(3.91)I_(0.18)-based ASSLMBs with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)cathode achieved ultrastable capacity retention rate of 95.8%after 300 cycles at 0.1 C.This work provides reliable strategy for designing advanced sulfide SSEs for commercial applications in ASSLMBs.