【作者】 黄红燕；

【导师】 艾红军；

【作者基本信息】 中国医科大学 ， 口腔临床医学， 2009， 博士

【摘要】 牙科修复材料发展经历了从异体牙齿、动物牙齿到现在采用的金属材料、树脂材料和陶瓷材料的过程。由于牙科陶瓷修复体形态色泽与天然齿类似,应用时显得自然、逼真。此外,瓷修复体质地致密、耐磨,表面光洁,菌斑不易附着,有良好的生物相容性,使用安全等其它材料所不具有的优点。因此,陶瓷已成为当前最常采用的制作义齿的材料。目前应用的牙科陶瓷有金属烤瓷牙和全瓷牙两类。牙科陶瓷合金（DentalCeramic Allloys,DCA）用于制作瓷熔附金属（PFM）修复体的金属底层。PFM修复体是临床上修复牙体、牙列缺损最常采用的一类修复体,它不仅具有金属的韧性和强度,同时兼有瓷的美观性和耐磨性,因此是一种较理想的修复方法。自1950年在美国出现以来,取得了迅速的发展。我国在80年代后期引进此种技术,现已成为目前口腔修复的最主要方法。在临床上,据粗略统计,70%以上的修复病例采用此种方法。烤瓷牙的适应症是非常广泛的,变色牙、畸形牙、牙面发育不良,牙体较大缺损无法充填修补的牙,牙错位、扭转等不宜或不能作正畸治疗的牙,牙缺失后基牙条件符合生物力学要求的牙,均可考虑做烤瓷牙。烤瓷牙的类型主要根据瓷粉和内冠金属的成份来区分,林林总总,可供选择的一般有二、三十种。目前国内使用的瓷粉多为德国vita普通、vita3D、wieland、日本松风、瑞士义获嘉瓷粉,还有一些纳米瓷粉、低温瓷粉,它们各有特点、物理特性有一定差别,但都能满足一般牙齿功能要求。表面区别主要在于美学性能,例如,德国vita3D的比色体系更加完善,透明度、立体感更接近天然牙,日本松风瓷粉颜色红黄成份更多,更适合东方人的皮肤和天然牙。这些区别带给人的总体感觉有所差异,但肉眼下,一般人很难区分。因此,造成不同类型烤瓷牙品质差异的最大因素在于金属底冠所用合金成份。可供我们选择的合金有数十种,但可以归纳为两大类型,即普通金属烤瓷牙和贵金属烤瓷牙。普通金属烤瓷牙金属成份主要为镍铬合金,它的优点在于经济实用,是目前国内应用最多的烤瓷牙。缺点在于金属耐腐蚀性差,在口腔唾液和食物形成的复杂的电解质环境和酸碱环境中不够稳定。时间长（一般数年后）大多出现龈缘变黑（因金属离子的渗透）、红肿、出血、萎缩,影响美观和牙齿健康。因此普通烤瓷牙在国外越来越少有医生和客人去选用。普通烤瓷牙金属还有无铍合金、钛合金等选择,它们的理化性能能满足一定的要求,但达不到贵金属修复的效果。贵金属烤瓷采用贵金属底冠制作烤瓷牙,其中最好的、也是最有代表性的是黄金烤瓷（也叫金钯烤瓷,含86%黄金）,它的耐腐蚀性、延展性等理化性能优异,与瓷粉结合牢固,在唾液中不易氧化或析出,生物相容性极佳,牙颈部不会变色。目前在欧美国家大多数选用黄金烤瓷,它的缺点就是价格贵,一般是普通烤瓷牙的数倍。根据合金中金属成份的不同,贵金属烤瓷还有铂金（含铂15%左右）、钯金（含钯62%,金4%）等供选择,它们的特点是比黄金烤瓷便宜,性价比较高。目前国内口腔修复中较为常用的瓷熔附金属修复体（PFM）虽能解决强度问题,但其工艺复杂,而且金属底胎常常影响修复体的美观效果,因瓷体的脆性过大和与金属结合不良,而经常出现崩瓷失败,严重影响了临床的远期效果。而且目前普遍使用的Ni-Cr合金等金属在口腔内长期使用可能会溶出有毒的元素,这些对人体组织和器官都会有一定的潜在危害。与金属烤瓷牙冠相比,全陶瓷牙冠（全瓷冠）具有良好的生物相容性,能够栩栩如生地再现自然牙的色泽及色深度,越来越受到牙病患者的青睐。氧化锆复合陶瓷是其中优秀的代表。氧化锆增韧氧化铝（Zirconia-Toughening-Alumina,简记为ZTA）是比较典型的氧化锆增韧陶瓷,其强度在1200MPa,韧性在16MPa·m^1/2左右。ZTA优良的力学性能、生物相容性和较好的美观性广泛应用于牙科全瓷修复。目前已有多种系列的全瓷修复材料面世,如Procera Allceram、Vita In-Ceram、IPS·Empress 2和GⅠ·Ⅱ等。其中VITA公司生产的In-Ceram系列是迄今应用于临床最为成功的全瓷系列。In-Ceram陶瓷属于ZrO₂增韧的Al₂O₃陶瓷（ZTA,ZirconiaToughed Alumina）,其拥有足够的力学性能,可用于后牙冠桥修复。Mclaren等介绍了应用于全瓷固定桥并取得满意修复效果的玻璃渗透氧化锆/氧化铝基底陶瓷,Probster等用玻璃渗透氧化铝瓷核材料（In-Ceram）对患牙行全冠固定桥修复。观察表明该核材料的高抗弯强度（bending strength）使其能支撑桥架结构,并使修复体具有良好的边缘适合性及审美性。Suarez等对18例氧化锆增韧玻璃渗透陶瓷修复的后牙固定桥进行了为期3年的临床观察,只有1例因基牙根折失败,更长期的临床观察正在进行中。但是现有的全瓷材料也仍然存在着强度不够、加工工艺复杂以及韧性较低等缺陷,还未完全达到临床广泛应用的要求,如何提高该材料的韧性和抗冲击性已是研究的重点。合成高强度、高韧性的新型牙科全瓷材料,实现在现有牙科操作条件下将全瓷修复体的应用范围扩展到后牙冠、桥及桩冠等修复领域的目标,降低瓷粉及临床加工的成本,使全瓷修复技术可以真正应用于临床,提高口腔修复体的质量,促进全瓷修复体的运用与普及有重要意义。本文通过水溶胶法制备性能优良的氧化锆/氧化铝复合粉体,探讨了不同组分对复合粉体晶型晶貌的影响。比较了溶胶法和机械混合法制备材料的力学性能,探讨氧化锆氧化铝相互作用机制。采用水溶胶法制备Al₂O₃/ZrO₂复合粉体前驱体,研究原料浓度、分散剂、干燥方式、pH值对溶胶体系的影响,确定了适宜的反应条件:氨水反滴定方式、pH值为9.0、铝盐锆盐浓度为0.3mol/L、添加1wt.%PEG800+PEG2000、正丁醇共沸蒸馏干燥,制备的前驱粉体分散性好,粉体由近似球状的颗粒组成,颗粒粒径30nm左右。采用相同方法制备了不同组成的前驱体,复合粉体粒径在15-40nm左右。研究了pH值、煅烧温度和锆铝比例对粉体晶型晶貌的影响。采用XRD,IR,SEM等检测手段对制备的复合前驱粉体在煅烧过程中的性质变化进行表征。结果表明:随反应溶胶体系pH值递增和前驱粉体煅烧温度的增加,四方相衍射峰的强度增加,t-ZrO₂晶型发育渐好。适量的Al₂O₃颗粒能抑制ZrO₂晶粒的长大,氧化铝相对含量的增加,提高了氧化锆的结晶温度。溶胶法复合粉制备的材料比球磨混合粉制备的材料成分分布均匀,这是复合粉制备的材料的力学性能优异的原因。以水溶胶法制备的复合粉体为原料,制备了不同组分的烧结体。测量得出烧结体的相对致密度、抗弯强度、断裂韧性、硬度等性能优于对应组分的机械混合粉体为原料制备的烧结体。制备的锆铝摩尔比例为1的瓷体在1450℃下烧成最致密,其综合力学性能最佳,抗弯强度,断裂韧性和硬度分别为786MPa,8.3MPa·m^1/2,14.2GPa。通过对烧结体表面和断口SEM和XRD分析得知锆铝比例为1时,氧化锆氧化铝晶粒细小,结合致密,应力诱导相变对韧性提高贡献较大,断裂方式主要为沿晶断裂。通过一系列的生物相容性的检测手段对在1450℃烧结成型的ZrO₂/Al₂O₃复合陶瓷试件进行检测,其溶血实验阴性,毒性评级为0-1级,可以初步认为所检测的ZrO₂/Al₂O₃复合陶瓷材料作为牙科修复材料对人体是安全的。初步研究证明,本研究所制备的复合材料有近似于天然牙的体积密度,比天然牙高的强度和硬度以及优良的断裂韧性,能满足牙科材料的性能要求和特殊使用环境。更多还原

【Abstract】 The development of dental prosthetic materials go through from the variant teeth,animal teeth,metal material,resin material and procelain.The colour and figure of dental ceramic prosthetic materials were similar to natural tooth.Besides,ceramic prosthetic materials have the advantages that other materials don’t have,such as compact texure,good wear resistance,smooth surface,good biocompatibility and security.So ceramic prosthetic materials become the popular materials for false tooth.Dental ceramic materials were divided into metal-porcelain and porcelain in recent application.Dental Ceramic Alloys was used for metal button of porcelain fuse metal（PFM） restoration.PFM restoration was popular for dentition defect and tooth defect,which has the advantages of toughness and intensity of metal and beauty and good resistance of porcelain.This technology have developed quickly since 1950,it was introduced in our country in late 1980,and it become the major method for dental repair. The indications of metal-porcelain was very wide.Many situation were suitable for metal-porcelain,such as bad colour tooth,abnormal and torsion,and so on.Metal-porcelain was divided by ceramic powder and metallic inside conolar,it has thirty kinds more or less to choose.Most of them were from German （vita,vita3d,wieland） Japan and switzerl.They have their own different characters,but they can satisfy the request of dental function.The difference between them were esthetics.The colour of German vita3d was more perfect and transparent,it was more close to natural tooth.The colour of Japan tooth powder was more sutiable for easterner skin and tooth.The difference was hard to distinguish by people eyes.The quality difference between different metal-porcelain lied with alloy component of metallic inside conolar.There were few ten kinds of alloy to choose,and they can reduced to two types,which were common metal-porcelain and nobal metal-porcelain.The major component of common metal-porcelain was Cr-Ni Alloy,it was the most popular metal-porcelain because of economy.The defect of Cr-Ni Alloy was poor corrosion resistence and inadequate stable in the complicated Oral electrolytes and Acid-base Environment.The gum edge would changed black,red swelling,hemorrhage and shrink after severage year,which affect the beauty and health of tooth.So less doctor and patient choose common metal-porcelain overseas,common metal-porcelain also included freeBeryllium alloy and Titanium alloy.The physical and chemical property can satisfy a definite request,but it can not reach the best effect of nobal metal-porcelain.Gold-porcelain was the most typical roast Porcelain tooth.It showed good corrosion resistence,good ductibility performance,good biocompatibility,hard to oxide or precipitate,firm adhesion with porcelain powder and tooth cervical would not chang colour.Most occidental patient choose gold-porcelain,but the price is several times higher than common metal-porcelain.The nobal metal-porcelain also included palladium gold and platinum gold,they were more cheapper than gold-porcelain and had high ratio performence and price.The PFM tecnology can save the intensity problem,but the complex tecnics,poor aesthetic effect,procelain brittleness and bad adhesion with metal affect the long-term clinical effect.More over the Cr-Ni Alloy was likely to dissolve poisonous elements for long time use,which would do damage to tissues and organs.Compared to metal-porcelain,full porcelain showed good biocompatibility and the colour was semilar to natural tooth.It regains more and more dental patients favour. Zirconia-Toughening-Alumina ceramics was the typical full porcelain restoration.The intensity and toughness of it were 1200MPa and 16MPa·m^1/2 more or less.ZTA widely applied dental full porcelain restoration bacause of good mechanical properties,biocompatibility and good appearance.There were several kinds full porcelain restoration in the market,such as Procera Allceram,Vita In-Ceram,IPS·Empress 2 and GI·ⅡThe In-Ceram series from VITA company was the most successful restoration in clinic.In-Ceram belonged to Zirconia Toughed Alumina caramic.It possessed enough intensity for posterior tooth crown restoration.Mclaren intruduced the Dental Glass-infiltrated Zirconia/Alumina Composite ceramic,it was applied all-ceramic bridges restoration and reached satified effect.Probster studied Glass-infiltrated Alumina for all-ceramic restoration,the result showed the material can supposed frame structure because of its high bending strength,the restoration presented good marginal adaptation and perfect esthetic attribute.Suarez examined the Glass-infiltrated Zirconia caramic for posterior tooth crown restoration in clinic for 3 years,only one experiment fail,long time examination was on the way.But the existing full porcelain did not reach the widely standard of clinical application,they also had some limitations,such as inadequate intensity,complex tecnics,low toughness and so on.How to improve the toughness and shock resistance was the major problem.It was meaningful to synthesize high strength,high toughnss dental porcelain materials,expand full porcelain restoration applied areas,reduce ceramic powder and processing cost,improve the quality of porcelain restoration,Spur the applications and popularization of porcelain restoration.ZrO₂/Al₂O₃ composite porcelain has excellent biocompatibility and mechanical properties.lt is a proper dental prosthetic materials.This study prepared an excellent ZrO₂/Al₂O₃ composite precursor powder by sol method.The crystal transfomation at different hot treatment temperature and different component ratio was examined.Also the mechanical properties of porcelain prepared by sol method and mechanical mixing method was studied.The reaction mechanism between zirconia and alumina was discussed.The ZrO₂/Al₂O₃ composite podwer was prepared by sol method.The effect of the concentration of inorganic precursors,dispersing agent,drying method and pH value on sol solution were studied.The proper conditions was confirmed.The dispersion of precursor composite powder was better at pH=9.0,1wt%PEG800+PEG2000,the inorganic precursors’s concentration of 0.3mol/L,n-butanol azeotropic distillation,ammonia inverse titration method.The particles was spherical and the average particle size was 30nm.The effect ofpH value,calcined temperature and ratio of ZrO₂/Al₂O₃ on the crystal was studied.The result showed:the t-ZrO₂ intensities increaseed with the pH values of sol solution and calcined temperature.Proper alumina can inhibit the growth of zirconia grain.With the relative content of alumina increased,the crystallization temperature of zirconia improved.The mechanical properties of porcelain prepared by sol method was better than that prepared by mechanical mixing method.The Sem and EDS analysis also indicates that the composition which prepareed by sol method distribution was more homogeneous.The composite porcelain of different ratio of ZrO₂/Al₂O₃ were prepared by composite powder from sol method.The composite porcelain with 50at%zirconia content has the best mechanical properties as calcined at 1450℃,the flexural strength, fracture toughness and hardness were 786MPa,8.3MPa·m^1/2 and 14.2GPa.It can satisfy the clinical treatment request.The surface morphology and fracture characteristics were examined by SEM and XRD.The results showed that the grains of zirconia and alumina were small and combined tightly.Zirconia stress-induced phase transformation toughening effect plays an important role in improving the composite material fracture toughness.The fracture mode of the composites was mainly intracrystalline fracture.The results of heamolysis-test were negative in either of material.All the grades of cytotoxicity were 0-I.Nano ZrO₂/Al₂O₃ composite ceramics was pveliminarily safe for dental application.In the research,the composites of ZrO₂/Al₂O₃ ceramic have fine physical, chemical properties and aesthetics effect.The bulk density is close to that of natural dental,and the strength and rigidity are higher than it.It can satisfy the mechanical property request and special application environment.更多还原