【作者】 高婧；

【导师】 陈吉华；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2010， 博士

【摘要】 玻璃陶瓷是由基质玻璃通过控制晶化制得的晶相和玻璃相均匀分布的多晶固体。经过一定的热处理程序后,基质玻璃中的一部分玻璃相转化为晶相,提高了材料的强度;此外,由于玻璃相的存在,玻璃陶瓷展现出了良好的半透光性,可以很好地模拟自然牙的光泽与透光性。因此,玻璃陶瓷集中了陶瓷和玻璃的特点,实现了高强度和良好美观性的统一,成为前牙美学修复的首选材料。本课题的目的是研究前期制备的实验二硅酸锂玻璃陶瓷(ELDC)应用牙科热压铸工艺的可行性,分析热压铸处理对玻璃陶瓷微观结构和性能的影响,探讨实验玻璃陶瓷烧结过程的影响因素;评价实验玻璃陶瓷与氟磷灰石饰瓷之间的结合强度及其对冷热循环的敏感性,并分析不同的表面处理对结合强度的影响;采用烧结法二次着色工艺制备单色梯度实验玻璃陶瓷,研究添加色料添加对实验玻璃陶瓷性能的影响以及不同色料浓度对色度值和反射光谱的影响。本课题分为三部分:第一部分实验玻璃陶瓷应用牙科热压技术的研究1)分析不同的热压铸条件对实验玻璃陶瓷铸入百分比、挠曲强度的影响,筛选最佳的热压铸工艺参数。同时用该材料制备实验性修复体,探讨其应用牙科热压铸工艺加工全瓷修复体的可行性。结果表明,实验二硅酸锂玻璃陶瓷具有理想的热压铸性能,能够应用现有的牙科热压铸设备进行热压成型,并获得较高的力学性能。制作的实验性修复体外形完整,美观性好,展示了良好的应用前景。2)比较分析热压铸对实验玻璃陶瓷晶相组成和微观结构的影响,探讨微观结构与性能的关系。结果表明:热压铸对实验玻璃陶瓷的晶相组成和含量无显著影响,热压前后玻璃陶瓷均是以二硅酸锂为主晶相,另外还有少量的磷酸锂晶体。实验玻璃陶瓷经牙科热压铸处理后,晶体呈现出一定程度的定向排列趋势,弯曲强度提高。3)对三种不同粒度的实验二硅酸锂玻璃粉体在经过不同的热处理制度后的性能和微观结构进行比较,并分析热压铸前后不同粒度的玻璃陶瓷之间的性能和微观结构,探讨实验玻璃陶瓷烧结过程的影响因素。结果表明:玻璃粉体的粒度变化对实验玻璃陶瓷的烧结行为有显著影响。不同粒度的实验玻璃陶瓷热压前后的弯曲强度均有显著差异。第二部分实验玻璃陶瓷与饰瓷结合强度的相关研究4)评价实验二硅酸锂玻璃陶瓷与氟磷灰石饰瓷之间的结合强度及其对冷热循环的敏感性。结果表明:实验玻璃陶瓷与氟磷灰石饰瓷之间能够形成良好的结合,界面无任何裂隙存在,其结合强度值与IPS e.max系统无显著差异,能够满足临床需求。冷热循环对二者间的结合强度无显著影响,表明二硅酸锂玻璃陶瓷与氟磷灰石饰瓷结合界面的长期耐久性。5)分析实验玻璃陶瓷表面不同的处理方法对其与氟磷灰石饰瓷结合强度的影响。结果表明:不同的表面处理方法对实验玻璃陶瓷与饰瓷的结合强度有显著影响。其中,表面打磨配合喷砂处理能够获得最高的结合强度。第三部分实验二硅酸锂玻璃陶瓷的着色研究6)通过在基础玻璃粉中添加不同质量百分比的锆铁红、锆铈镨黄和镍黑三种高温陶瓷色釉料,通过改良的烧结法二次着色工艺进行着色研究。结果表明通过烧结法二次着色工艺能够制备整体内着色的不同浓度梯度的二硅酸锂玻璃陶瓷块,并且着色内外均匀、稳定。7)分析添加色料对实验玻璃陶瓷微观结构和力学性能的影响。结果表明:在实验采用的浓度范围内,添加三种色料对玻璃陶瓷陶瓷烧结体的机械性能、晶相结构以及微观形貌均无显著性影响,添加三种色料是安全可靠的,对烧结体的稳定性没有显著影响。8)研究了不同色料浓度对实验玻璃陶瓷色度值和反射光谱的影响。结果表明:三种不同的色料对实验玻璃陶瓷色度值的影响不同;随着色料浓度的增加,在特定的光谱吸收波长区内,光谱反射率曲线呈现出良好的递减趋势,而全波长K/S曲线则呈现出良好的递增趋势;本实验中所得的单色基础数据基本符合计算机配色数据库的要求。更多还原

【Abstract】 Glass-ceramics are fine-grained polycrystalline materials based on suitable heat treatment and controlled crystallization. After heat treatment, the glass-ceramics can obtain high mechanical strength owing to the crystalline phase; also, due to a certain content of glass phase, the glass-ceramics show high translucent characteristic. Thus, in dental aesthetic restorations, glass-ceramics have the advantages of both glass and ceramic. The aim of the present study was to analyze the possibility of application of experimental glass-ceramic in heat-pressing technique and study the influence of heat-pressing technique on microstructure and properties of experimental glass-ceramic; The shear bond strength between experimental glass-ceramic and veneering ceramics and their susceptibility to thermocycling was investigated. We also analyzed the influence of different surface treatments on the bond strength and fabricated glass-ceramic blocks by appending the pigments with sintering technology.The whole studies were divided into three parts:PartⅠ: The possibility of application of experimental glass-ceramics in dental heat-pressing technique1. The feasibility of processing experimental glass-ceramics with current dental heat-pressing equipments was verified and all-ceramic restoratives made with experimental lithium disilicate glass-ceramic showed good performances.2. The effect of heat-pressing technique on the crystalline phases and microstructure of experimental lithium disilicate glass-ceramics was studied. It was showed that dental heat-pressing had no influence on the crystalline composition. Li2Si2O5 represented the main crystalline phase before or after heat-pressing technique. After pressing, crystals aligned along the direction of pressing and glass-ceramics showed higher mechanical strength than these before heat pressing.3. The properties and microstructure of experimental glass-ceramics with different glass powder before and after pressing were compared. Results showed that grain size has a significant effect on the sintering behavior and mechanical properties of the experimental glass-ceramics both before and after heat pressing.Part two: the research on the bonding strength between experimental glass-ceramics and veneering ceramics4. The shear bonding strength between experimental glass-ceramic and veneering ceramics were investigated. No gap was found at the interface between experimental glass-ceramic core and veneering ceramic. And thermocycling had no significant effect on the bonding strength, indicated better long-term durability.5. The effect of different surface treatmentss on the bonding strength was evaluated. It was showed that different surface treatments had a significant effect on bond strength between experimental glass-ceramic and veneering ceramics. Polishing followed with sandblasting could achieve higher bond strength.Part three: the research on the coloration of experimental glass-ceramics 6. Three kinds of pigments with different concentrations were added into base glass powder, then subjected to heat treatment for developing glass- ceramics. Results demonstrated that colored glass-ceramics with good uniformity and color stability were achieved.7. To evaluate the effect of addition of different pigments on the microstructure and properties of experimental glass-ceramics. Results showed that crystalline composition, mechanical properties and microstructure of experimental glass-ceramics were not influenced by adding pigments.8. To investigate the effect of pigments concentration on the color values and to validate if the relationship between pigments concentration and reflective spectrums is suitable for computer color matching. The results indicated that adding three pigments had significant influence on value L, value a and value b, respectively. The relationship between pigments concentrations and chroma value met the principles of color characteristic, which could be regaded as database while establishing computer-color-matching software.更多还原