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。     

天然牙与全瓷饰面瓷的磨损特性研究

目的通过体外模拟实验观察全瓷饰面瓷材料（Vintage AL、Vita- alpha）与天然牙釉质的摩擦学行为特点,探讨其摩擦磨损机制。方法实验前对材料进行力学性能检测。采用摩擦磨损机观察3种材料的摩擦磨损行为,记录摩擦力矩数,计算摩擦系数;测量磨斑宽度;磨损试件表面采用动态原子力显维镜（DFM）观察;采用能谱仪分析摩擦实验前后样品元素的变化。结果3种材料显微硬度值存在统计学差异（P<0.05）;两种饰面瓷的三点弯曲强度比较有统计学差异（P<0.05）,断裂韧性差别无统计学意义。3种材料摩擦系数呈现一定时间规律性,耐磨能由高到低排列为Vintage AL、Vita- alpha、天然牙釉质。磨斑宽度比较有统计学意义（P<0.05）。DFM结果显示釉质主要表现为磨粒磨损和组织结构的变形,偶可见组织断裂片;饰面瓷摩擦表面可见大量犁沟和磨粒,偶见微裂。结论本实验中3种材料呈现良好的耐磨性。天然牙的磨损机理主要是磨粒磨损和组织结构变形;全瓷饰面瓷的磨损机理主要为磨粒磨损、黏着磨损和疲劳磨损,不同磨损类型在两种饰面瓷发挥的作用不完全相同。     

五种充填用流动性复合树脂的耐磨性能研究

目的比较5种充填用流动性复合树脂的耐磨性能,为临床选择适用于[牙合]力承担区直接充填治疗的流动性复合树脂提供参考。方法以可压实复合树脂(Majesty)为对照组,选用5种充填用流动性复合树脂(A组:Filtex 350 XT Flow;B组:Beautifil Flowable Plus;C组:Clearfil Majesty LV2;D组:Unifil LoFlo Plus;E组:Sonic Fill组)为研究对象,每组材料制备6个半球形试件。在微摩擦磨损实验机下,树脂试件垂直加载20 N,与牛牙釉质往复对磨1万次后测量球头磨斑直径并在扫描电镜下观察磨斑微观形貌。采用单因素方差分析比较各组磨斑直径差异。结果对照组、A、B组磨斑直径[分别为(1033±43)、(1068±48)、(1237±86)μm]差异无统计学意义(P>0.05),C、D、E组磨斑直径[分别为(1550±150)、(1384±222)、(1525±81)μm]均显著大于对照组和A组(P<0.05)。扫描电镜显示,对照组、A、B组填料粒度范围较大,磨耗面可见填料的碎裂和局部缺损;C、D、E组填料颗粒较小,并可见多处整块填料脱落的痕迹。结论填料粒度范围大的流动性复合树脂的耐磨性能与可压实复合树脂相当,有望用于[牙合]力承担区直接充填治疗。     

五种充填用流动性复合树脂的耐磨性能研究

目的比较5种充填用流动性复合树脂的耐磨性能,为临床选择适用于力承担区直接充填治疗的流动性复合树脂提供参考。方法以可压实复合树脂(Majesty)为对照组,选用5种充填用流动性复合树脂(A组:Filtex 350 XT Flow;B组:Beautifil Flowable Plus;C组:Clearfil Majesty LV2;D组:Unifil LoFlo Plus;E组:Sonic Fill组)为研究对象,每组材料制备6个半球形试件。在微摩擦磨损实验机下,树脂试件垂直加载20 N,与牛牙釉质往复对磨1万次后测量球头磨斑直径并在扫描电镜下观察磨斑微观形貌。采用单因素方差分析比较各组磨斑直径差异。结果对照组、A、B组磨斑直径[分别为(1 033±43)、(1 068±48)、(1 237±86) μm]差异无统计学意义(P>0.05),C、D、E组磨斑直径[分别为(1 550±150)、(1 384±222)、(1 525±81) μm ]均显著大于对照组和A组(P<0.05)。扫描电镜显示,对照组、A、B组填料粒度范围较大,磨耗面可见填料的碎裂和局部缺损;C、D、E组填料...     

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.     

磨损过程中pH值改变对复合树脂磨耗性能的影响

目的:研究4种充填用复合树脂材料:Beautifit(B),SureFilTM(S),TE-Econom(T),Charisma(C)与牙釉质对磨,改变人工唾液pH值,对树脂材料与牙釉质磨耗性能的影响.方法:利用UMT-2微摩擦磨损实验机模拟复合树脂与牙釉质磨耗,计算树脂磨耗质量丧失量,扫描电镜观察磨耗后表面形貌.结果:SEM显示,B、S树脂中无机填料颗粒体积较大,C树脂相埘较小且均匀.4种树脂无机填料颗粒周围均出现裂纹和脱落迹象,牙釉质在酸性环境浸泡时磨损表面出现特征性变化.S,C,T 3种树脂较耐磨损;人工唾液pH值南6.8降为4.0时,B、S、T 3种树脂磨损量显著增加,C磨损量变化不显著.结论:不同品牌的复合树脂与牙釉质对磨时,耐磨性不同;降低pH值可以加速某些复合树脂的磨损.     

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。     

飞秒激光切削牙齿硬组织表面粗糙度和显微形貌观察

目的 初步建立飞秒激光数控切削牙齿硬组织模拟实验平台并观察显微形貌,以期为飞秒激光的临床应用提供依据.方法 用人离体第三磨牙制备牙釉质和牙本质平面样本各1个;通用运动控制器控制样本在与激光入射方向垂直的焦点平面内做矩形波轨迹运动.激光扫描共聚焦显微镜测量切削面粗糙度,扫描电镜观察显微形貌.结果 用实验建立的飞秒激光数控切削平台制备牙釉质和牙本质正方形窝洞各1个.窝洞边界清晰、底平壁直.牙釉质激光扫描线内底部粗糙度7.173 μm,侧壁粗糙度2.675μm;窝洞底壁粗糙度13.667 μm,侧壁粗糙度33.927 μm.牙本质窝洞底壁粗糙度51.182 μm,侧壁粗糙度25.629 μm.扫描电镜下牙釉质未见微裂隙及碳化,牙本质出现碳化、少量裂隙和结晶颗粒.结论 飞秒激光数控切削能实现精确牙体切削,切削面侧壁粗糙度小于底面,可满足临床修复要求.但应针对不同切削对象设置适宜的飞秒激光能量密度,其过高时可造成组织损伤.     

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。     

Wear of opposing teeth by posterior composite resins--evaluation of newly developed wear test methods

In the present study, enamel wear against indirect composite resins was evaluated using two newly designed wear test methods: a rotating sliding wear test and a buff wear test. For the composite resins investigated in this study, their surface morphologies were examined using a scanning probe microscope after buff-polishing. After the wear tests, enamel was worn down by hard fillers that protruded from the abraded resin matrices. Notably, enamel wear was induced by composite materials with a Vickers hardness number (VHN) greater than 45 and that the amount of enamel wear increased with increasing hardness of the composite material. Therefore, 45 VHN was the critical hardness value for composite resins at which antagonistic enamel wear would occur. Besides, the D-value obtained from the buff wear test indicated not only the relative wear resistance of the composite resin itself, but also its potential risk to induce antagonistic enamel wear.     

Evaluation of the wear resistance of new nanocomposite resin restorative materials

STATEMENT OF PROBLEM: The use of composite resins for the restoration of posterior teeth is popular because of the improved performance and appearance of these materials. Wear resistance continues to be of particular importance when restoring large occlusal areas in posterior teeth. PURPOSE: The purpose of this study was to evaluate the relative wear characteristics of 2 recently introduced nanofiller-based composite resins (Filtek Supreme, Premise) and compare them to the more traditional microhybrid (Point 4) and microfill (Heliomolar RO) materials that have been used for many years. MATERIAL AND METHODS: Six specimens (2 mm thick and 15 mm in diameter) of each material were subjected to 3-body wear tests using the Oregon Health Sciences University Oral Wear Simulator to produce abrasive wear and attrition for all specimens using human enamel as the opposing cusp. Profilometric tracings of the worn surfaces were used to determine the relative abrasive wear, attrition wear, and roughness (Ra) of the composite resin substrate. The mean diameter of the antagonist enamel wear facets was determined under a measuring microscope. Qualitative SEM analysis was also used to assess the surface appearance of the resulting enamel and composite resin wear facets. The data were analyzed by 1-way ANOVA and Tukey's multiple range post hoc test (alpha=.05). RESULTS: The results indicated that the composite resin type did not significantly affect the amount of measured attrition (P=.15) but did significantly affect abrasive wear (P=.02). The conventional microfill composite resin (Heliomolar RO) exhibited significantly less abrasive wear than the nanohybrid material (Premise). There was no significant difference in the average size of the opposing enamel wear facet generated by the different composite resin materials. Heliomolar RO resulted in a significantly rougher surface within the wear track than either nanohybrid composite resin (Premise) or microhybrid composite resin (Point 4) but was not significantly different than nanofilled composite resin (Filtek Supreme). CONCLUSIONS: The incorporation of nanofillers in 2 of the composite resin materials tested did not significantly improve their wear resistance or the amount of opposing cusp wear when compared to the traditional materials tested.     

In vitro two-body wear of inlay-onlay composite resin restoratives

Inlay-onlay composite resin restorations have been introduced to the profession as alternatives to amalgam and direct composite resins. Two-body wear testing was performed on three inlay-onlay resins and one direct composite resins using a machine designed to produce sliding wear. The composite resins were opposed by human enamel, type III gold alloy, and porcelain. Of the investigated materials, the homogeneously microfilled inlay-onlay material showed significantly less wear. The direct composite resin showed significantly the greatest wear. The hybrid inlay-onlay resins showed intermediate wear. The hybrid inlay-onlay resins and the direct composite (small particle, heavily filled) resin created wear tracks in the opposing surfaces while the homogeneous microfill inlay-onlay resin did not. The depth of the observed wear tracks in the opposing surface was sufficiently substantial to warrant further investigation into the wear of materials that oppose composite resin restorations.     

Study of wear of restorative materials and teeth-antagonists in vitro

Since clinical evaluation of wear turns out to be particularly time consuming, a standardized method was developed to model oral mastication. So-called artificial mouth was used to assess the extent of wear caused from different restorative materials in contact with bovine enamel. Ball heads manufactured from modern veneering ceramics, gold alloy, amalgam and resin composite materials were loaded with a contact load of 50 N for 200,000 chewing cycles. Additional thermo-cycling (5 degrees /55 degrees C) for 2,500 cycles was conducted in the artificial mouth. The worn surfaces, both on the material specimens and on the antagonist bovine enamel surfaces were volumetrically scanned under a laser microscope. Negligible wear rates were observed for the veneering ceramics and for the gold alloy. Most veneering ceramics as well as the resin composite materials caused low wear on the antagonist enamel surfaces. In contrast, the antagonist enamel was significantly damaged in contact with amalgam or some of the ceramic materials. However, modern veneering ceramics as well as gold alloys might be recommended in occlusally loaded contact with the antagonist enamel, whereas resin composite materials might be indicated for non load-bearing areas. Ceramics are contraindicated in case of bruxism.     

冷热循环老化对可切削复合树脂表面粗糙度的影响

目的：研究冷热循环老化对可切削复合树脂材料粗糙度的影响。方法以可切削复合树脂A( Lava Ultimate ,3M ESPE)、B(High-Class, AMBORINO)、C(Hyramic 润瓷, Upcera)为实验组,以光固化复合树脂 D ( Ceramage, Shofu)和二硅酸锂玻璃陶瓷E( UP-CAD, Upcera)为对照组,分别在老化前和经5000及10000次冷热循环后测量表面粗糙度( Ra),并观察表面形貌,进行统计学分析。结果在老化前,D和E组间Ra值差异有统计学意义(P<0.05),其余各组间Ra值差异均无统计学意义。经冷热循环老化实验,A、B、C和E四组材料冷热循环前后材料表面粗糙度Ra值的差异均无统计学意义;D组材料冷热循环前后,材料表面粗糙度Ra值的差异有显著统计学意义(P<0.001)。结论经冷热循环老化后,可切削复合树脂和玻璃陶瓷表面粗糙度较为稳定,而光固化复合树脂粗糙度增加。     

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。     

Discoloration of manually fabricated resins and industrially fabricated CAD/CAM blocks versus glass-ceramic: effect of storage media, duration, and subsequent polishing

This study determined the discoloration of five CAD/CAM resins, four manually polymerized resins, and glass-ceramic as control group. Specimens were divided into three groups (N=300, n=30) to be stored in coffee, black tea and red wine (n=10). The discoloration was measured using a spectrophotometer after 1, 7, 29, 90, 180 days storage. All tested groups showed color change (ΔE) at all time points. The manually polymerized resin composites GD (Gradia) and CM (CronMix K), and the CAD/CAM resin composite HC (Blanc High-class) showed significantly higher ΔE compared to all other groups in all tested media. The discoloration was extrinsic and decreased after polishing for the majority of the tested materials. Except CAD/CAM resin HC (Blanc High-class), all CAD/CAM resins showed similar color stability compared to the control group.     

Radiopacity of computer-aided design/computer-aided manufacturing composite resin blocks

This study aimed to clarify the degree of difference in radiopacity between sixteen CAD/CAM composite resin blocks, one ceramic block, and teeth of the same thickness on radiographs. The radiographic density of CAD/CAM composite resin blocks was measured and the results were compared with the corresponding values for enamel and dentin. Additionally, the study analyzed the constituent elements of each type of CAD/CAM composite resin block and conducted an examination to identify those elements exerting an influence on radiopacity. Compared to the enamel, there were five blocks with significantly higher radiopacity, two blocks with the same level in radiopacity, and ten blocks with notably lower radiopacity. Compared to the dentin, there were ten blocks with significantly higher radiopacity, one block with the same level in radiopacity, and six blocks with notably lower radiopacity. All of the CAD/CAM composite resin blocks for molars contained barium and strontium. This result suggests that the addition of heavy metals, for example, barium, strontium, and zirconium, would be effective in providing CAD/CAM composite resin blocks with radiopacity.     

Wear evaluation of MZ100 compared to ceramic CAD/CAM materials

The material and antagonist wear of two CAD/CAM ceramic materials, the laboratory-processed IPS Empress ceramic, and the composite mill block material MZ100 were tested in an artificial wear simulator with human enamel as the antagonistic material. The material samples underwent 50,000 test cycles (1 cycle per second, 50 N) in distilled water. The wear of the material samples and of the opposing enamel was documented after 30,000 and 50,000 cycles with replicas, digitized, and evaluated with a 3D evaluation system. The loss of volume and height caused by wear was calculated. No significant difference between the ceramic materials could be found either in the amount of material or in the amount of antagonist wear. The material wear of MZ100 differed significantly from Vita Mark II only in terms of volume loss. Regarding height loss, MZ100 exhibited a significantly higher wear than all ceramic materials. The wear of the enamel antagonists does not differ significantly between the ceramic materials. With MZ100, however, a significantly smaller amount of enamel wear was found when compared with Empress and Vita Mark II. Despite the highest material wear, MZ100 had the lowest material wear rate, the lowest enamel wear rate, and the lowest total wear rate. The laboratory-processed IPS Empress material had a clearly higher material wear rate than the CAD/CAM materials.