【作者】 袁坤；

【导师】 陈吉华； 王富；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2013， 博士

【摘要】 二硅酸锂玻璃陶瓷由于其晶体独特的性质和分布，是目前强度最高的一类牙科璃陶瓷，并具备良好的半透光特性，为牙科美学修复的理想材料，具有广阔的应前景。Ivoclar Vivadent公司的IPS系列产品是目前市场上仅有的商品化牙科二硅酸玻璃陶瓷，品种单一，修复成本较高。为突破国外厂商的技术垄断并推广全瓷修的应用，需进一步研发出具有自主知识产权和较低成本的新型产品。性能的提高颜色的调配是牙科陶瓷材料研发的两大阻碍。课题组前期已制备出可用于牙科修的实验二硅酸锂玻璃陶瓷，本课题在前期工作的基础上，通过分析晶化热处理时对实验二硅酸锂玻璃陶瓷微观结构和性能的影响，优化热处理时间，进一步提高能；研究锆基陶瓷色料对实验玻璃陶瓷颜色、微观结构和性能的影响，探讨其用实验玻璃陶瓷配色的可能性；采用计算机配色技术进行配色研究，筛选出与Vitapanlassical比色板颜色相匹配的色料配方；比较三种计算机配色方法配色的准确性，建立计算机配色数据库，为进一步的色彩学研究奠定基础；分析饰面瓷烧结对实验玻璃陶瓷颜色的影响；并对牙科二硅酸锂玻璃陶瓷的微观结构和性能进行比较分析。通过本课题的研究，为研发拥有自主知识产权的新型牙科二硅酸锂玻璃陶瓷产品奠定实验基础。本课题共分为三部分：第一部分实验二硅酸锂玻璃陶瓷的性能分析1.采用两段式晶化热处理制度（700℃/900℃）制备出SiO2-Li2O-K2O-Al2O3-ZrO2-P2O5系玻璃陶瓷，两段式晶化热处理时间分别为：A，1h/1h；B，2h/2h；C，3h/3h；D，4h/4h；E，5h/5h；F，6h/6h；G，8h/8h。XRD结果表明，使用不同的晶化热处理时间制备出的实验玻璃陶瓷的晶相组成相似，主晶相均为Li2Si2O5，次晶相均为Li2SiO3和Li3PO4。SEM结果显示，各组棒状的Li2Si2O5晶体形成互锁微结构，但各组晶体的大小及分布均随热处理时间的不同而存在差异。不同的热处理时间对实验玻璃陶瓷的透明度无显著影响。经两段式晶化热处理5h制备出的实验玻璃陶瓷具有最高的弯曲强度：308±25MPa。2.在实验玻璃陶瓷中分别添加1.0wt.%锆镨黄、锆铁红和锆钒蓝三种锆基色料，分析色料添加对其微观结构和性能的影响。结果表明，添加1.0wt.%锆基色料对实验玻璃陶瓷的热力学性能、晶相组成、微观结构和弯曲强度均无显著影响。添加1.0wt.%锆基色料后，实验玻璃陶瓷的透明度发生显著变化，但均能满足临床应用要求。三种锆基色料可用于实验玻璃陶瓷的配色研究。第二部分实验二硅酸锂玻璃陶瓷的计算机配色3.在实验玻璃陶瓷中分别添加梯度质量百分比浓度的锆镨黄、锆铁红和锆钒蓝，制备出单色梯度浓度色样瓷块，研究不同色料浓度对瓷块色度值和反射光谱的影响。结果显示，三种锆基色料的添加浓度与色样瓷块的色度值之间的关系符合色料着色的基本规律，且光谱反射率数据可用于建立计算机配色的单色数据库。4.采用基于Kubelka-Munk理论的三刺激值和全光谱匹配法，以Vitapan Classical比色板为靶目标样，对实验玻璃陶瓷进行计算机配色研究。结果表明，根据三刺激值和全光谱匹配法提供的色料配方烧制的配色样，均能获得与Vitapan Classical比色板各比色片相近的颜色，其中全光谱匹配法配色精度优于三刺激值法，二者的配色样与靶目标样之间的平均色差分别为10.8±2.1和14.0±2.2。5.采用基于BP人工神经网络的计算机配色方法，以Vitapan Classical比色板为靶目标样，对实验玻璃陶瓷进行配色研究。结果表明，根据BP人工神经网络提供的色料配方烧制的配色样，可获得与Vitapan Classical比色板各比色片相一致的颜色，其配色样与靶目标样之间的平均色差为6.3±1.2，配色精度优于三刺激值和全光谱匹配法。6.在实验玻璃陶瓷基底瓷上烧结IPS e.max Ceram饰面瓷，对其烧结饰面瓷后的颜色进行评价，并根据饰面瓷的烧结程序对A2色实验玻璃陶瓷进行反复烧结，以研究饰面瓷反复烧结对其颜色的影响。结果表明，烧结IPS e.max Ceram饰面瓷后，实验玻璃陶瓷与Vitapan Classical比色板各比色片之间的平均色差减小至3.5±0.4，且反复烧结对实验玻璃陶瓷的颜色无影响。第三部分牙科二硅酸锂玻璃陶瓷的比较分析7.对实验玻璃陶瓷与IPS e.max Press瓷块的微观结构和性能进行比较分析，探讨二硅酸锂玻璃陶瓷性能和结构之间的关系。结果表明，实验玻璃陶瓷与IPS e.maxPress瓷块的晶相组成、微观结构和机械性能均相近，其透明度介于IPS e.max PressMO和HO瓷块之间。实验玻璃陶瓷的性能符合牙科美学修复材料的要求，展现出理想的应用前景。更多还原

【Abstract】 Lithium disilicate glass-ceramic possesses higher mechanical strength than otherdental glass-ceramics and meanwhile demonstrates excellent translucency characteristicsdue to the unique nature and distribution of Li2Si2O5crystals. Therefore, it has beenconsidered as the ideal aesthetic restorative material with board applications in cosmeticdentistry. Currently, IPS products manufactured by Ivoclar Vivadent Corporate are theonly commercial dental lithium disilicate glass-ceramics with high cost. In order to breakthe technological monopoly of foreign manufacturers and to promote the application ofall-ceramic restorations in China, new products with independent intellectual propertyrights and lower cost need to be developed. Property improvement and color matching aretwo main difficulties of developing new dental ceramics. In the previous study, a novel dental lithium disilicate glass-ceramic has been produced. In the present study, the effectof the sintering time and zircon-based ceramic pigments on the microstructure andproperties of experimental lithium disilicate glass-ceramic were investigated, in order toimprove the properties of the experimental glass-ceramic by optimizing the sintering timeand to investgate whether zircon-based tricolor pigments can be used to color theexperimental glass-ceramic. Moreover, computer color matching of the experimentalglass-ceramic was conducted to procure pigment formulations matching with the color ofthe Vitapan Classical shade guide. Besides, the color matching accuracies of threecomputer color matching methods were evaluated with the aim of establishing colormatching database for further color research. Furthermore, the effect of veneeringporcelain on the color of the experimental glass-ceramic was studied. And finally, themicrostructure and properties of the experimental glass-ceramic were compared with thoseof commercial dental lithium disilicate glass-ceramics. Based on these studies, we aimedto develop a novel dental lithium disilicate glass-ceramic product with intellectualproperty. The present study includes three parts:Part I: property analysis of the experimental lithium disilicate glass-ceramic1. Glass-ceramics derived from the SiO2-Li2O-K2O-Al2O3-ZrO2-P2O5system wereproduced by a two-stage sintering cycle with a primary thermal treatment at700oCfollowed by a secondary thermal treatment at900oC. The periods during which thematerials were subjected to each temperature level (700oC/900oC) were the following: A,1h/1h; B,2h/2h; C,3h/3h; D,4h/4h; E,5h/5h; F,6h/6h; G,8h/8h. The XRD resultsrevealed that all groups had a similar crystalline structure though the sintering times weredifferent. The main crystalline phase corresponds to Li2Si2O5and the minor phasescorrespond to Li2SiO3and Li3PO4. SEM analysis showed an interlocking microstructureof rod-shaped Li2Si2O5crystals in all specimens. However, the glass-ceramics producedwith different sintering times showed different crystal sizes and spatial distribution. Thetranslucency parameters (TP) of the glass-ceramics studied were not affected by sinteringtime since similar TP values were observed in all specimens. The glass-ceramic sinteredduring5h in each temperature level (700oC/900oC) showed the highest flexural strength (308±25MPa).2.1.0wt.%zircon-based tricolor pigments (praseodymium zircon yellow, ferrumzircon red and vanadium zircon blue) were added into the experimental glass-ceramic andtheir effects on the microstructure and properties of the experimental glass-ceramic wereinvestigated. The results revealed that the three pigments had no significant effects on thethermal property, crystalline phase composition, microstructure and flexural strength ofthe experimental glass-ceramic. Although significant differences (P<0.05) were observedbetween the translucencies of the uncolored and1.0wt.%zircon-based pigment coloredceramics, the translucencies of the latter were sufficient to fabricate dental restorations.These results indicate that the zircon-based tricolor pigments could be used as thecolorants of the experimental glass-ceramic.Part II: computer color matching of the experimental lithium disilicate glass-ceramic3. Monochrome colored experimental glass-ceramic samples with gradient addedconcentrations of zircon-based tricolor pigments were fabricated. The effect of thepigments on the chromatic values and reflective spectrums of the monochrome sampleswere investigated. The results indicated that the relationship between the addedconcentration of pigments and the chromatic values was consistent with the basic law ofpigmentation, and that the spectral reflectance data of monochrome samples could be usedto establish the database of computer color matching.4. Computer color matching methods based on Kubelka-Munk theory, namely,tristimulus matching method and spectrophometic matching method, were applied forcolor matching of the experimental glass-ceramic with Vitapan Classical shade guide. Theresults showed that the samples sintered according to the pigment formula provided bythese two computer color matching methods both achieved similar colors with the shadetabs of Vitapan Classical shade guide. However, spectrophometic matching method wassuperior to tristimulus matching method in color matching precision, and the average colordifferences (ΔE) between the matching samples of these two methods and the target shadetabs were10.8±2.1and14.0±2.2, respectively. 5. Computer color matching method based on BP artificial neural network was usedto match the color of the experimental glass-ceramic with Vitapan Classical shade guide.The results demonstrated that the samples sintered according to the pigment formulaprovided by BP artificial neural network also obtained similar colors with the shade tabsof Vitapan Classical shade guide. Moreover, this method showed better color matchingaccuracy than both tristimulus and spectrophometic matching methods, with smalleraverage color differences between the matching samples and the target shade tabs(6.3±1.2).6. IPS e.max Ceram veneering porcelain was fired on the experimental glass-ceramiccore materials and the colors of the samples fired with veneering porcelain were evaluated.Additionally, the effect of repeated firing according to the firing program of IPS e.maxCeram on the color of A2colored experimental glass-ceramic was investigated, in order todetermine color stability of the colored experimental glass-ceramic. The resultsdemonstrated that average color differences between the samples fired with veneeringporcelain and the target shade tabs were reduced to3.5±0.4. Moreover, repeated firing hadno significant effect on the color of the experimental glass-ceramic.Part III: comparative analysis on the microstructure and properties of dental lithiumdisilicate glass-ceramics7. The microstructure and properties of the experimental glass-ceramic and IPSe.max Press ceramic blocks were compared, with aim to analyze the relationship betweenthe properties and microstructure of lithium disilicate glass-ceramic. The results showedthat the crystalline phase composition, microstructure and mechanical properties of theexperimental glass ceramic were similar to those of IPS e.max Press ceramic blocks. Thetranslucency parameters of the experimental glass ceramic were higher than those of IPSe.max Press HO ceramic blocks but lower than those of MO ceramic blocks. The resultsverified that the experimental lithium disilicate glass-ceramic possesses sufficientperformance that comply with the requirements of dental aesthetic restorative materialsand demonstrates ideal application prospects.更多还原