牙科氧化锆瓷摩擦磨损性能的研究

目的研究牙科氧化锆瓷的摩擦磨损性能以及与天然牙釉质摩擦磨损性能匹配情况。方法微摩擦磨损试验机上,以滑石瓷为对磨物,人工唾液润滑下对Upcera ST和Zenostar Zr Translucent氧化锆瓷、牙釉质和饰面瓷进行摩擦磨损实验。实验前,用激光共聚焦显微镜测试件表面粗糙度Ra;实验结束后,光学显微镜下观察滑石瓷磨斑形貌、测量滑石瓷磨斑面积;激光共聚焦显微镜测量试件磨斑宽度;扫描电镜下观察试件磨斑的微观形貌。采用单因素方差分析进行统计学分析。结果饰面瓷的磨斑宽度大于其它3种材料（P〈0.01）,饰面瓷对磨物滑石瓷磨斑面积大于氧化锆瓷和牙釉质（P〈0.05）。结论与饰面瓷对比,氧化锆瓷具有更佳耐磨性及较低对磨物磨损,并且与天然牙釉质的磨擦学性能相似。     

两种不同氧化钇含量的牙科氧化锆瓷与牙釉质的摩擦磨损性能

目的：通过体外模拟实验考察两种不同氧化钇含量的牙科氧化锆瓷与天然牙釉质的摩擦磨损性能。方法：选择两种不同氧化钇含量的牙科氧化锆瓷UpceraST（3mo1％Y2O3-ZrO2）与Upcera TT（3mo1％Y20-ZrO2＋8mo1％Y2O3-ZrO2）在微摩擦磨损试验机上,人工唾液润滑下与天然牙釉质进行摩擦磨损实验。两种氧化锆瓷表面分别采用抛光和打磨处理。用激光共聚焦显微镜测量牙釉质磨斑宽度,扫描电子显微镜观察氧化锆瓷及牙釉质磨斑微观形貌。采用配对t检验进行统计学分析。结果：牙釉质与氧化钇含量相对较低的UpceraST对磨的磨斑宽度：抛光组474．2±18．0μm,打磨组581．5±32．7Win;牙釉质与氧化钇含量相对较高的UpceraTT对磨的磨斑宽度：抛光组476．8±33．7μm,打磨组591．3±55．7μm。不同氧化钇含量的氧化锆瓷采用相同的表面处理方式对牙釉质的磨耗无统计学差异（P〉0．05）。牙釉质磨斑宽度在不同表面处理组间差异有统计学意义（P〈0．01）：牙釉质与抛光氧化锆瓷对磨的磨斑宽度值小于打磨组。结论：两种不同氧化钇含量的氧化锆瓷摩擦磨损性能相似;氧化锆瓷表面抛光可避免牙釉质过度磨损。与抛光氧化锆瓷对磨,牙釉质的磨损类型主要是疲劳磨损;与打磨氧化锆瓷对磨,牙釉质的磨损类型主要是磨粒磨损。提示临床在对充填体或修复体调磨后应进行抛光处理,以避免造成对颌天然牙的过度磨损。     

多次烧结对Cercon饰面瓷磨损特性的影响

目的探讨多次烧结对Cercon全瓷饰面瓷磨损性能的影响。方法采用体外实验模拟口腔环境,观察多次烧结后Cercon饰面瓷的磨损行为。实验中测量磨斑宽度以比较磨斑大小;采用扫描电镜（SEM）和原子力显微镜（AFM）观察磨斑形貌。结果随着烧结次数的增加,Cercon饰面瓷磨斑增大;磨斑宽度和烧结次数间存在着正相关（P＜0.01）;磨斑差异具有统计学意义（P＜0.05）。SEM和AFM观察结果发现,随着烧结次数增多,犁沟减少,组织缺隙明显。结论多次烧结可以降低Cercon全瓷饰面瓷抗磨损性能,磨损模式有向严重磨损发展的趋势。     

不同口腔修复材料与天然牙耐磨性能的比较

目的：通过体外模拟实验对几种口腔修复材料与天然牙釉质的磨耗性能进行对比研究并探讨其机制.方法：（1）将钴铬合金,纯钛,氧化锆陶瓷,Ceramage聚合瓷制成符合规格的试件.（2）将上颌第一前磨牙磨改,作为对照组.（3）将滑石瓷制做圆盘状,作为与试件及天然牙对磨的材料.（4）所有实验均在人工唾液环境中加载测试.（5）SPSS17.0软件进行统计学处理,对磨耗后的试件进行磨痕形貌的观察.结果：（1）纯钛的磨耗量与牙釉质最接近.钴铬合金与氧化锆陶瓷无统计学意义（P＞0.05）,其余各组之间均有统计学意义（P＞0.05）.磨耗后质量损失量的大小顺序为纯钛＞牙釉质＞ Ceramage聚合瓷＞氧化锆陶瓷＞钴铬合金.（2）钴铬合金：磨粒磨损,同时伴有粘着磨损.纯钛：以粘着磨耗为主,伴有磨粒磨耗.氧化锆陶瓷：磨粒磨损.Ceramage聚合瓷：主要是磨粒磨损和粘着磨损,伴有疲劳磨损.天然牙：粘着磨损和磨粒磨损.结论：（1）纯钛的耐磨性低于牙釉质但与牙釉质最为相近,是一种良好的修复材料.（2）钴铬合金与氧化锆陶瓷的耐磨性能接近,均可对天然牙釉质造成过度磨耗.（3）修复材料的耐磨性能受其微观结构的影响.     

酸性环境下饰面瓷的摩擦磨损行为研究

目的研究在酸性饮料环境中2种饰面瓷Vitamaster和Ceramco3的摩擦磨损行为。方法采用努氏显微硬度仪测其表面硬度;在可口可乐环境下通过Plint微动磨损实验机评价饰面瓷的摩擦磨损性能并对磨斑进行三维重建,用表面轮廓仪测量磨痕深度,计算磨损体积。用扫描电子显微镜和激光共聚焦扫描显微镜观察饰面瓷的微观结构和表面磨损形貌特征。对Vitamaster和Ceramco3的努氏硬度、磨斑体积和平均磨损深度进行艟验。结果2种饰面瓷的微观结构不同,酸蚀后Vitamaster的晶体呈现融合现象,Ceramco3的晶体呈现脆性脱落。Vitamaster的硬度低于Ceramco3的硬度,但Vitamaster的磨损深度、磨损体积和稳定摩擦系数也低于Ceramco3。Vitamaster的三维重建磨斑为带有犁沟的不规则四边形;磨损形貌主要为粗大而深且密集均匀分布的犁沟。Ceramco3的三维重建磨斑为规则的椭圆形;磨损形貌主要为剥层和磨屑。结论2种饰面瓷的硬度和酸性介质下的摩擦磨损行为没有直接关系;在酸性饮料环境下,Vitamaster和Ceramco3的摩擦磨损行为存在较大差异,Vitamaster的磨损机制以磨粒磨损为主;Ceramco3的磨损机制主要为裂纹的萌生和扩展。     

可切削复合树脂材料磨损性能的研究

目的：研究可切削复合树脂材料与天然牙釉质磨损性能的匹配情况。方法在微摩擦磨损实验机上,模拟口腔力学和化学环境,以三种新型的可切削复合树脂材料( Upcera 复合树脂、Lava Ultimate、High-Class)为研究对象,天然牙釉质为对磨物。实验前,用激光共聚焦显微镜测试试件表面粗糙度Sa,实验后,激光共聚焦下观察可切削复合树脂试件的磨斑形貌、测量其磨斑面积及对磨物牙釉质的磨斑宽度,扫描电镜下观察试件磨斑的微观形貌。采用单因素方差分析进行统计学分析。结果牙釉质的磨斑面积和磨斑宽度大于其他三种可切削复合树脂材料(P<0.05)。结论与牙釉质相比,三种可切削复合树脂具有更佳的耐磨性及较低的对磨物磨损。     

树脂牙与天然牙釉质摩擦磨损性能的研究

目的：研究两种常用树脂牙摩擦磨损性能及与牙釉质摩擦磨损性能的匹配情况。方法：采用销盘式摩擦磨损试验机,通过体外模拟口腔环境,对牙釉质、松风牙,拜耳牙进行摩擦磨损试验,记录动态摩擦系数,采用电子扫描电镜观察表面磨损形貌,电子天平得出磨损量。结果：三者摩擦系数变化趋势相似,牙釉质稳态摩擦系数为0.90～1.00,松风牙为0.38,拜耳牙为0.47。磨损体积量：牙釉质〈松风牙〈拜耳牙（P〈0.05）,而对磨物滑石瓷体积磨损量：拜耳牙〈松风牙〈牙釉质（P〈0.05）。树脂牙的磨损机制主要为磨粒磨损,牙釉质磨损机制主要为疲劳磨损。结论：两种树脂牙稳态摩擦系数显著低于牙釉质,耐磨性弱于牙釉质,松风牙耐磨性大于拜耳牙。     

4种齿科金属材料与牙釉质耐磨损性能的研究

目的：研究齿科金属材料耐磨损性能及与牙釉质耐磨损性能的匹配情况。方法：使用MMV-1立式万能摩擦磨损试验机,以天然牙釉质为对照,滑石瓷为对磨物,在人工唾液,37℃试验工况下,对口腔修复用金钯合金、银钯合金、纯钛,镍铬合金进行二体摩擦磨损试验。采用扫描电镜观察表面磨损形貌,x线衍射能谱仪分析磨屑成分,显微硬度仪测试表面硬度,电子天平得出磨损量。结果：4种金属材料自身磨损量和对磨物磨损量与牙釉质均有统计学差异（P〈0.05）,其中金钯合金及对磨物与牙釉质及对磨物最接近。金属试样使滑石瓷体积磨损量与其硬度值间存在显著性正相关关系（相关系数r=0.95,P〈0.05）。金属材料的磨损机制主要是黏着磨损和磨粒磨损,牙釉质的磨损机制主要是疲劳磨损。结论：金钯合金耐磨损性能与牙釉质最相匹配,作为固定修复材料比镍铬合金、纯钛、银钯合金更具有优越性。     

氟磷灰石玻璃陶瓷、长石质饰瓷与天然牙摩擦磨损性能的研究

目的：研究牙科氟磷灰石玻璃陶瓷、长石质饰瓷与天然牙在干摩擦和唾液润滑条件下的摩擦磨损学性能。方法：制备涂覆IPS-emaxcream和Vita vm9 2种饰面瓷的氧化锆-饰面瓷双层材料试样,尺寸为20 mm×20 mm×4.5 mm,各20个。利用MMV-1摩擦磨损试验机,通过设置不同大小的垂直载荷和转速,分别在干摩擦和唾液润滑条件下,对2种氧化锆-饰面瓷试样进行摩擦磨损试验。采用SPSS 17.0软件包进行单因素方差分析和t检验,确定各组间摩擦系数和磨损量是否存在差异。结果：氟磷灰石玻璃陶瓷在唾液润滑条件下的动态摩擦系数和磨损量显著大于干摩擦条件下的数值;与氟磷灰石玻璃陶瓷相反,长石质饰瓷在干摩擦时的动态摩擦系数和磨损量显著大于在唾液润滑条件下的数值。在干摩擦和唾液润滑条件下,氟磷灰石玻璃陶瓷的磨损量均小于长石质饰瓷。扫描电镜显示,在唾液润滑条件下,氟磷灰石玻璃陶瓷及对应天然牙表现出比干摩擦更为严重的磨损表面。在干摩擦条件下,长石质饰瓷及对应天然牙较氟磷灰石玻璃陶瓷磨损更为严重,在唾液润滑条件下差异较小。结论：与长石质饰瓷相比,氟磷灰石玻璃陶瓷与天然牙在干摩擦条件下表现出更优越的耐磨损性能。加入唾液后,能减少2种饰瓷摩擦磨损性能之间的差异。     

6种不同修复材料与天然牙牙釉质摩擦、磨耗性能的比较

目的：通过体外摩擦、磨耗实验,比较临床常用的陶瓷材料、多种合金及天然牙釉质的摩擦、磨耗性能,为临床上选择与对颌牙磨耗性能相近的修复材料,更好地保护对颌牙提供一定的实验依据。方法：将陶瓷、纯钛、钛合金、镍铬合金、金钯合金、银汞合金和近期拔除的成人下颌第三磨牙的釉质平面,与滑石瓷磨头磨耗机上对磨。耐磨性能的评定采用称重法。用针一盘磨损试验仪测定各种材料的滑动摩擦系数。应用SPSS11．5软件包进行统计学处理．对各试件、天然牙的质量损失量进行统计学分析,对比分析摩擦系数。结果：单位面积的磨损量以天然牙釉质最小,但与瓷块、银汞合金、金钯合金无显著性差异（P〉0．05）,与其余各组均有显著性差异（P〈0．01）;纯钛最大,与其余各组均有显著性差异（P〈0．01）,镍铬合金、金钯合金与其余各组均有显著性差异（P〈0．01）。瓷块的摩擦系数稳定在0．68,银汞合金的摩擦系数为0．12,金钯合金的摩擦系数为0．11,镍铬合金为0.41,纯钛为0.38,钛合金为0．48,天然牙釉质为0．65。结论：6种修复材料的耐磨性均比天然牙釉质差．纯钛的耐磨性最小,钛合金及镍铬合金、金钯合金次之,陶瓷的耐磨性最大。     

牙科硅藻土基底瓷与饰面瓷的结合机制分析

目的 检测硅藻土基纳米复相基底瓷与不同饰面瓷的结合强度,观察结合界面的微观结构并分析元素分布,探讨结合界面的匹配性。方法采用热膨胀仪检测硅藻土纳米复相基底瓷的热膨胀系数,在基底瓷上分别烧结氧化铝饰面瓷（A组）、钛瓷饰面瓷（B组）及E-max饰面瓷（C组）,检测基底瓷与饰面瓷的剪切强度,扫描电镜（SEM）及能谱仪（EDS）观察结合界面的显微结构及元素分布。采用SPSS 17.0软件包对数据进行单因素方差分析。结果硅藻土基纳米复相基底瓷在25~500℃之间的热膨胀系数值为8.85×10^-6 K^-1。硅藻土基底瓷与C组剪切强度最佳,C组与A组间及C组与B组之间相比有显著差异（P<0.05）。SEM及EDS发现,C组结合界面紧密,界线不清晰,无明显间隙,界面两侧元素存在渗透。结论硅藻土基纳米复相基底瓷与E-max饰面瓷具有较好的剪切强度,两者间匹配性较好。     

氧化锆和金属基底饰面瓷机械性能与微观结构的比较研究

目的比较分析氧化锆和金属基底饰面瓷的机械性能及微观结构。方法选择5种氧化锆基底饰面瓷Vintage ZR(ZR),Cerabien ZR(CZR),VitaVM9(VM9),Cercon ceram KISS(KISS),IPS e.max ceram(e.max)及烤瓷熔附金属用饰面瓷Vintage MP(MP)。每种饰面瓷各制作10个试件,测定表面粗糙度﹑三点弯曲强度(ISO 6872)和维氏硬度。计算断裂韧性。微观结构通过X射线衍射和扫描电镜分析。结果与其它饰面瓷相比,氧化锆基底用KISS的弯曲强度最高(P﹤0.05),CZR的弯曲强度最低(P﹤0.05);金属基底用MP的断裂韧性明显高于所有氧化锆用饰面瓷(P﹤0.001)。结论与氧化锆基底用饰面瓷相比较,金属基底用饰面瓷不易断裂,更具有临床可靠性。     

Current status of zirconia restoration

During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia restoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed.Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain.There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is currently one of the most reliable bonding systems for zirconia. Adhesive treatments could be applied to luting the restorations and fabricating hybrid-structured FDPs. Full-contour zirconia FDPs caused concern about the wear of antagonist enamel, because the hardness of Y-TZP was over double that of porcelain. However, this review demonstrates that highly polished zirconia yielded lower antagonist wear compared with porcelains. Polishing of zirconia is possible, but glazing is not recommended for the surface finish of zirconia.Clinical data since 2010 are included in this review. The zirconia frameworks rarely got damaged in many cases and complications often occurred in the veneering ceramic materials. Further clinical studies with larger sample sizes and longer follow-up periods are required to investigate the possible influencing factors of technical failures.     

Effects of ageing on surface textures of veneering ceramics for zirconia frameworks

ObjectivesTo evaluate the effects of ageing on surface textures of veneering ceramics for zirconia frameworks.MethodsFive different veneering ceramics for zirconia frameworks, Vintage ZR (ZR), Cerabien ZR (CZR), VitaVM9 (VM9), Cercon ceram KISS (KISS), and IPS e.max ceram (e.max), and one veneering ceramic with metal frameworks, Vintage MP (MP), were evaluated. Twenty specimens were fabricated from each veneering ceramic. All specimens were divided into two groups, one of which was subjected to accelerated ageing. The other was used as the control. Accelerated ageing was performed on the distilled water for 5 h at 200 °C and 2 atm. Surface textures were examined using laser profilometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS).ResultsCompared to unaged specimens, surface roughness parameters (Ra, Rp, Rv) of all aged specimens except e.max were significantly greater (P = 0.000). Compared to the unaged specimens, sodium and potassium on the surfaces of all the aged specimens significantly decreased (P < 0.05). However, oxygen levels increased significantly (P < 0.05). Silicon showed a tendency to decrease in all aged specimens, and that of ZR, KISS and e.max have a significant decrease (P < 0.01). Numerous ruffled cracks were observed on the surfaces of all aged specimens, as shown by SEM. The peaks of all crystalline phases on the surfaces of all specimens changed after accelerated ageing.ConclusionSurface textures of all examined veneering ceramics were changed by the accelerated ageing test.     

Two-body wear of dental porcelain and substructure oxide ceramics

The aim of this in vitro study was to investigate the two-body wear of different ceramics. Two-body wear tests were performed in a chewing simulator with steatite and enamel antagonists, respectively. Specimens were loaded in a pin-on-block design with a vertical load of 50 N for 1.2 × 10(5) cycles; (f = 1.6 Hz; lateral movement, 1 mm; mouth opening: 2 mm). Human enamel was used as a reference. Three zirconia ceramics, three veneering porcelains, two glass-infiltrated and one lithium disilicate ceramic were investigated. Veneering and lithium disilicate ceramics were glazed before testing. Surface roughness Ra (SP6, Perthen-Feinprüf, G) and wear depth were determined using a 3D scanner (Laserscan 3D, Willytec, G). SEM (Quanta FEG 400, FEI, USA) pictures of the worn specimens and antagonists were made for evaluating wear performance. Veneering porcelain provided wear traces between 71.2 and 124.1 μm (enamel antagonist) and 117.4 and 274.1 μm (steatite). Wear of the steatite antagonists varied between 0.618 and 2.85 mm2. No wear was found for zirconia and glass-infiltrated substructure ceramics. Also, no wear was found for the corresponding antagonists. Wear of specimens and antagonists was strongly material dependent. No visible wear was found on zirconia and glass-infiltrated ceramics. Porcelain and lithium disilicate ceramic showed a comparable or lower wear than the enamel reference. Antagonist wear was found to be lower when specimens were made of substructure oxide ceramics instead of veneering porcelain. From the point of wear testing, zirconia may be used for the fabrication of fixed dental prosthesis without veneering.     

钇稳定氧化锆基底材料与饰面瓷结合性能的实验研究

目的考察国产氧化钇稳定四方晶体氧化锆（3Y-TZP）与4种氧化锆专用饰面瓷界面的结合性能。方法粉浆涂塑方法分别将VITA VM9、SHOFU VINTAGE ZR、IPS e.max Ceram、Cercon ceram kiss 4种氧化锆专用饰面瓷烧结在15 mm×5 mm×5 mm的3Y-TZP核瓷试件上,另外制作相同尺寸镍铬合金烤瓷试件作为对照,测试界面剪切强度。制作氧化锆基底与饰面瓷双层瓷试件,扫描电镜（SEM）观察结合界面微观形貌;能谱分析（EDS）检测界面元素分布。结果氧化锆与VITA VM9、SHOFU VINTAGE ZR、IPS e.max Ceram、Cercon ceram kiss 4种氧化锆专用饰面瓷的剪切强度分别为（18.83±1.77）MPa、（23.83±7.05）MPa、（17.87±2.30）MPa、（22.26±7.45）MPa,各组与金属烤瓷对照组比较,差异均无统计学意义（P＞0.05）。各3Y-TZP烤瓷组试件破坏模式以界面破坏为主。扫描电镜观察氧化锆和饰面瓷结合界面结合紧密;能谱分析结果显示二者存在化学元素渗透。结论国产3Y-TZP与饰面瓷材料界面结合良好,可以满足临床需要。