【作者】 宋君祥；

【导师】 冉均国；

【作者基本信息】 四川大学 ， 生物医学工程， 2004， 博士

【摘要】 烤瓷牙是目前适合度最好，美观效果最为逼真的口腔修复体。牙科现用陶瓷材料主要包括长石瓷、铝瓷和玻璃陶瓷三大类，其中以长石瓷最常采用。牙科陶瓷属于脆性材料，瓷修复体在就位、承受咬合力和意外创伤时易于折裂。提高牙科陶瓷强度一直是牙医和陶瓷学家所追求的目标。目前在烤瓷粉研究中存在的问题有： (1)基础理论研究不够：如从经验上控制白榴石相的形成；金属和瓷体间的界面特征模糊，对于两者间的结合力种类、量化、烧结特性缺乏深入研究；对于烤瓷粉中遮色瓷、体瓷、切端瓷的接口特性、烧结特性和渗透扩散特性研究甚少；对烤瓷粉的流变特性，包括粉体的粒度分布、形貌对流变模型、流变参数的研究报道甚少。由于缺乏理论指导，导致在烤瓷牙的制作过程中，技工仅凭经验控制粉体与水的调和，使得其修复体的强度、颜色效果等难以保证，成品率低。 (2)制备工艺老化：烤瓷粉的制作几乎均用传统的加热工艺来达到熔融、析晶，白榴石相析晶的量、晶粒尺寸、分布、形貌难以理想化，导致制作的修复体瓷崩、瓷裂现象时有发生。 (3)冠表面处理手段落后：金属底层冠表面处理手段落后，例如仅凭经验控制金属底层氧化的厚度，很难达到金瓷间理想的结合强度。 (4)凭经验控制瓷层颜色：技工仅能凭经验试制瓷层颜色，人为的因素影响了美观效果。提高金属熔附烤瓷性能的研究 针对上述问题，本文重点进行如下六个方面提高烤瓷性能的研究: (l)研究制备白榴石微晶熔块的三段式热处理新工艺:白榴石的膨胀系数高达27x 10一6/℃，它的存在可以提高瓷釉的膨胀系数。为了制备结合强度高的烤瓷粉，本文利用国产优质钾长石为原料，通过热处理，研究了从0、A12o:加入量的影响，借助XRD衍射、显微结构分析来确定形成白榴石晶体的优化熔融温度、成核温度、晶化温度，制备白榴石牙用烤瓷微晶玻璃。改进了传统的热处理工艺，获得了较佳的三段式热处理温度制度为:熔融温度1250℃，成核温度900℃，晶化温度为1000℃。在三段式热处理、流水淬火新工艺下，可以得到40%以上的析晶，晶粒0.8一1.0林m、晶粒呈层状断口的白榴石微晶玻璃。 (2)金属烤瓷粉的制备是将预合成的白榴石微晶熔块和优质钾长石及各种添加剂按比例粉碎混合而成。实验发现:遮色瓷的颗粒粗，瓷质透明性好，密度较低，强度也低。要求粒度分布应满足0<D<E，其目的是使遮色瓷的遮色效果好，防止透出金属色。研制的遮色瓷(O)、体瓷(D)与牙釉质瓷(E)平均粒度分别为8.03脚、10.10和13，95卿。在瓷粉组成不变的条件下，适当地减小瓷粉粒度是一种促进快速烧结的有效途径。本课题研究的遮色瓷与日本松风遮色瓷XRD图谱基本相同。由SEM照片可以看出，所研制的两种遮色瓷中的白榴石微晶相都是较均匀地分布于基质中。 (3)提高金瓷结合强度的研究:瓷熔附于金属的强度主要受遮色瓷的化学成分、组成比、粒度等因素影响。遮色瓷粉由玻璃相与结晶相组成，在烧烤过程中，遮色瓷粉与金属基体氧化物层反应，形成金属一瓷结合。本研究通过检测金一瓷结合强度，采用扫描电镜(sEM)观察金一瓷界面的结合状况，评价遮色瓷与金属表面的结合情况。研究了白榴石微晶强化陶瓷的膨胀性能，探讨了白榴石微晶的含量对该玻璃陶瓷强度的影响。 结果表明，研制的遮色瓷在白榴石含量为30一35%左右时，与日本shofu遮色瓷相比，其抗压强度、径向抗张强度等无太大差异(P>0.1);但研制的遮色瓷弯曲强度低于日本shofu遮色瓷。尽管如此，研制的遮色瓷弯曲强度虽然低于Shofu瓷，但其弯曲强度值(7s.4Mpa一83.SMpa)却符合150所规定的标准(>soMPa)。研究表明遮色瓷的化学成分及组分是金属一烤瓷结合强度的重要影响因素之一。瓷粉结晶相及非结晶相的成分及二者的比例，既影响界面的氧化还原反应，又影响陶瓷金属表面的润湿性，从而影响金属一烤瓷结合强度。白榴石熔块粉的加入四川大学博士学位论文量在40%左右，可以算出瓷粉中白榴石的含量在5%~15%之间，最佳含量在12一14%左右。 (4)等离子体纳米表面处理提高牙科合金金瓷结合性的研究:目前主要利用氧化法、电沉积法和喷涂法在合金表面生成一层氧化物的方法来提高金瓷的结合强度，但在实际应用中烤瓷与金属底层冠存在结合不牢固的问题，主要是这些方法表面处理时清洁效果差，氧化物粒度较大，不利于化学、物理结合，从而影响了它的使用。为了避免以上缺陷，本文在复合离子镀装置中将牙科合金底层冠基体材料置于加负偏压的样品台上，盖上挡板，当条件适宜时，真空室中的Ai气产生辉光放电，等离子体流中的Ar+在负偏压的作用下对基体材料进行轰击，将材料表面的杂质颗粒、吸附粒子和不良氧化层刻蚀清除，在真空中暴露出材料的新鲜表面，使其具有活性表面。研究的重点是在牙科合金与烤瓷之间引入纳米氧化物过渡层，从而提高二者的结合强度。氧化物过渡层的厚度将影响牙科合金与烤瓷粉的结合强度，为此，首先将确定一定条件下的沉积速率。通过离子轰击溅射清洁和刻蚀合金材料表面的杂质颗粒、吸附粒子和清除不良氧化层，表面结构更有利于氧化膜的依附，并更多还原

【Abstract】 The enamel tooth is the best dental restoration materials at present. Ceramics materials used in dental clinic mainly is main current in the way of the ceramics materials and consists of the feldspar porcelain, alumina porcelain and glass ceramics, the feldspar porcelain is most constantly adopted. The dental ceramics pertains to the brittle materials, and it is feeble to disperse the part stress capability , and possesses low interfacial tension to meet an emergency , and the book snaps that the preceding deformation be able to stand is 0.1% around .To improve strength of dental ceramics materials is always the target that is pursued by dental physicians and material scientists. There are some problems of the porcelain in the research at present as follows:(l)The basic theory is researched insufficiently : Controlling the formation of leucite is based on experience; The interface feature between metal and the porcelain is not clear.The sort and guantification of interface adhesion, sintering performance are lacking in deep research; The properties of interface, sintering and osmosis diffusing for the porcelain such as opaque, body and incisal are little researched. The investigation on rheological properties including rheological model, distribution and morphology of powder particles has not been reported in literature. Since it is lacking in theory direction, porcelain tooth technicians work merely according to their experience. Thus the strength and color effect of dental restoration is difficult to guarantee, the yield of products is low.(2)Preparing process is aging: The manufacture of porcelain powder nearly is used by tradition heating technology to attain to melt, and crystallize; moreover theblending means of powder falls behind. The crystallizing amount, grain size distribution and morphology of leucite particles are difficult to the idealize, it results in crumbling prosthesis and cracking porcelain usually.(3)The treating technique of crown surface falls behind: The treating techniqueof metal crown surface fall behind , for instance, controlling the oxidizing thickness of metal crown according to experience merely ,it is difficult to attain good adhesive strength between metal and porcelain.(4) Controlling the the color on porcelain layer according to experience: Technicians can merely be able to lean against the experience to measure system porcelain layer color, the man-made factor effects the beautiful effect.Aim at above statement, the studies on increase in properties of porcelain will be mainly carried out in the following six aspects in the present thesis:(l)Study on the new process of preparing leucite crystallite using there step heat treatment:Expansion coefficient of leucite reaches 27 X 10-6 , it can increase in expansion coefficient of porcelain glaze. In order to prepare the porcelain powder having high adhesive strength, the high quality potassium feldspar is used as the raw materials, by heat treatment, the study on effects of K2O and Al2O3 amounts on properties of powders is carried out. By means of XRD diffraction and microstructure analysis, the optimal processing parameters such as melt temperature, nucleation temperature and crystalline temperature of preparing leucite crystallite have been obtained. The melt temperature is 1250 , nucleation temperature is 900 , the crystalline temperature is 1000 . By using this new process, the obtained amounts of the leucite crystalline over 40%, the size of crystalline grain is 0.8 -1.0 m. The morphology of crystalline grain on the fracture of leucite micro-crystalline glass presents tiering shape.(2) Process of preparing the porcelain powder: the leucite micro- crystalline glass is mixed into raw materials by proper proportion to obtain porcelain powder. It has been shown that the larger size of opaque porcelain is, the better the transparency, the lower the intensity and the strengthis. The grain size distribution is met the need for 0<D<E, so that the opaque porcelain well covers the color of metal. It resultsfrom that this can prevent fro更多还原