硅烷偶联剂的用量对PMMA/纳米ZrO2复合材料挠曲性能的影响

目的：研究硅烷偶联剂Z-6030的不同用量对聚甲基丙烯酸甲酯（PMMA）／纳米ZrO2复合材料挠曲强度的影响。方法：采用不同用量的硅烷偶联剂Z-6030，在丙酮溶液中对纳米ZrO2颗粒进行表面修饰，将经过表面修饰的纳米ZrO2颗粒按照3．0％的添加量，利用原位聚合生成法，与义齿基托树脂（聚甲基丙烯酸甲酯，PMMA）11型粉剂及液剂聚合生成分散良好的PMMA／纳米ZrO2义齿基托复合材料，参照IS01567：1999的标准，制作实验组的标准试件。用未添加纳米ZrO2颗粒及偶联剂的义齿基托树脂（聚甲基丙烯酸甲酯，PMMA）Ⅱ型粉剂及液剂制作普通基托组的标准试件。用添加未经表面修饰的纳米ZrO2颗粒的义齿基托树脂（聚甲基丙烯酸甲酯，PMMA）Ⅱ型粉剂及液剂制作对照组的标准试件。用三点弯曲试验测试材料的挠曲强度，采用SAS6．12软件包对结果进行单因素方差分析。结果：硅烷偶联剂Z-6030的用量为3．5％组的挠曲强度最大，与普通基托组、对照组、2．0％组、4．0％组、4．5％组、5．0％组有显著性差异（P〈0．05），0．5％组、1．0％组、1．5％组、2．5％组、3．0％组、3．5％组各组间的挠曲强度差异无统计学意义（P〉0．05）。0．5％组、1．0％组、1．5％组、2．0％组、2．5％组、3．0％组、4．0％组、4．5％组、5．0％组、普通基托组及对照组各组之间的挠曲强度的差异无统计学意义（P〉0．05）。结论：适当用量的硅烷偶联剂Z-6030可以提高PMMA／纳米ZrO2义齿基托复合材料的挠曲强度，硅烷偶联剂Z-6030的最佳用量为纳米ZrO2颗粒质量的3．5％。     

硅烷偶联剂用量对硼酸铝晶须增强PMMA挠曲强度影响的研究

目的研究硅烷偶联剂用量对硼酸铝晶须增强聚甲基丙烯酸甲酯(PMMA)挠曲强度的影响。方法使用质量分数为1.0%、2.0%、3.0%、4.0%的硅烷偶联剂Z-6030对硼酸铝晶须进行表面处理,未经处理的为对照组。把经过处理的硼酸铝晶须以10%添加量与PMMA混合,合成硼酸铝晶须/PMMA复合材料,制成标准试件5组。最后进行3点弯曲测试并且每组随机选出1个试件进行断面扫描电镜观察。结果5组的抗弯强度分别是67.59±5.35、72.96±4.20、75.52±4.89、71.26±5.94、(68.25±3.43)MPa。当硅烷偶联剂的用量为硼酸铝晶须质量的2.0%时,挠曲强度达到最大。利用SAS统计软件对5组的结果进行均数间的两两比较(Newman-Keuls检验)分析可知,硼酸铝晶须/PMMA复合材料各组间挠曲强度的差异无统计学意义(P>0.05)。断面的电镜扫描可见以2.0%硅烷偶联剂修饰硼酸铝晶须时,晶须与树脂间的结合牢固,且其在基质中分散也良好。结论使用硅烷偶联剂能够提高硼酸铝晶须与PMMA树脂间的结合强度,改善其在树脂基质中的分散性,提高复合材料的物理机械性能,但过多或过少均会影响复合材料的强度。针对本实验所使用的晶须、偶联剂以及偶联化方法,硼酸铝晶须用于增强PMMA时最佳的硅烷偶联剂使用量为2.0%。     

氧化锆的用量对纳米氧化锆/PMMA复合材料挠曲性能的影响

目的：研究氧化锆的添加量对纳米ZrO2/PMMA复合材料挠曲强度的影响。方法：采用球磨仪混合基托树脂（聚甲基丙烯酸甲酯,PMMA）Ⅱ型粉剂和硅烷偶联剂Z-6030修饰过的纳米氧化锆粉体,合成纳米ZrO2/PMMA复合材料,按照氧化锆的用量从0%到7%,制作8组标准试件,测试材料的挠曲强度。结果：氧化锆添加量为3%组的挠曲强度最大,与实验组中的4%组无统计学上的差异,与空白组及实验组中的其他组均有统计学上的差异（P〈0.05）,SEM观察断裂面为韧性断裂,其中3%和4%两组断裂面比较的粗糙。结论：经过硅烷修饰的纳米ZrO2颗粒,在其添加量为3.0%时,可以显著地提高纳米ZrO2/PMMA复合材料的挠曲强度。     

一种新型纳米SiC无纺布对PMMA机械性能的增韧作用研究

目的：研究纳米SiC无纺布对PMMA挠曲强度和杨氏弹性模量的增韧作用。方法：将已预先处理过的纳米SiC无纺布按照厚度1.0 mm、1.5 mm、2.0 mm的填入形式,合成3组SiC无纺布/PMMA复合材料,未添加的纯PMMA为对照组,进行三点弯曲实验,检测每组试件的挠曲强度和杨氏弹性模量。结果：与对照组比较,纳米SiC无纺布对PMMA的挠曲强度增强效果显著（P〈0.01）,当SiC无纺布填入的厚度为2.0 mm时,复合材料的挠曲强度达到最大值：（103.44±5.59）MPa,且此时复合材料的杨氏弹性模量也得到明显提高,与对照组相比差异显著（P〈0.05）。结论：纳米SiC无纺布对PMMA的机械性能有增韧作用,当填入的SiC无纺布厚度为2.0 mm时,复合材料能够获得较佳的力学性能。     

氧化锌晶须填料对义齿基托树脂力学性能的影响

目的：研究添加氧化锌晶须对基托树脂力学性能的影响。方法：将氧化锌晶须按不同的质量百分比加人基托粉中,分为空白对照组、1％、3％、5％、7％等5组。根据ISO标准测试各组的力学性能,并对试样断面进行扫描电镜观察。结果：随着氧化锌晶须用量的增加,复合材料的弯曲强度、弯曲弹性模量、显微维氏硬度呈先升后降的趋势。当氧化锌晶须用量为5％时,以上指标测得值最高,分别为（109．00±2．70）MPa、（3645．30±198．68）MPa、（20．57±0．85）kg／mm^2,树脂基托较对照组弯曲强度提高18．29％、弯曲弹性模量提高16．07％、显微维氏硬度提高29．94％。结论：氧化锌晶须填料显著增强了基托树脂的力学性能。     

纳米氧化锆对PMMA挠曲强度和表面硬度的影响

目的:研究纳米ZrO2的添加量对聚甲基丙烯酸甲酯(PMMA)基托树脂机械性能的影响。方法:使用质量分数为1.5%的硅烷偶联剂Z-6030对纳米ZrO2颗粒进行表面处理及FTIR表征分析,未经处理者为对照组。将经过表面处理的纳米ZrO2颗粒按照质量比0.5%、1%、1.5%、2%、2.5%、3%和3.5%的添加量与PMMA混合,合成纳米ZrO2/PMMA复合材料,共7组。制作标准试件,进行表面硬度测试和三点弯曲测试,从每组中随机选取1个试件进行扫描电镜观察。采用SAS 6.12软件包对数据进行ANOVA单因素方差分析。结果:红外光谱图显示,经过表面处理的纳米ZrO2颗粒表面有硅烷偶联剂吸附。纳米ZrO2添加量为1.5%和2%组复合材料的表面硬度最佳(P<0.05)。1.5%组复合材料的挠曲强度最高(P<0.05),SEM观察断裂面为韧性断裂。结论:使用硅烷偶联剂能提高纳米ZrO2与PMMA的结合强度,经过表面处理的纳米ZrO2,能提高复合材料的机械性能,但加入量会影响纳米ZrO2的增强作用。纳米ZrO2以1.5%和2%的添加比例对基托材料的表面硬度增强效果最佳,以1.5%的添加比例对PMMA挠曲强度的增强效果最...     

硅烷偶联剂的用量对钛酸钾晶须增强复合树脂的抗弯强度的影响

目的：研究硅烷偶联剂用量对钛酸钾晶须增强复合树脂抗弯强度的影响。方法：分别采用0．5％、1％、2％、3％、4%（质量比）的硅烷偶联剂KH-570对钛酸钾晶须进行表面处理,再以60％（质量比）的填充量把处理过的5组晶须混合到树脂基质中,并制成标准试件,进行三点弯曲测试及断面的电镜扫描。结果：5组试件的抗弯强度分别是（98．55±12．01）Mpa、（100．60±17．39）MPa、（107．80±5．25）MPa、（134．18±12．90）MPa、（102．15±10．36）MPa,对其进行均数间的两两比较（Tukey检验）可知,3％硅烷偶联剂处理组的抗弯强度在α=0．01的水平上与其它组结果具有显著性差异,其余4组间差异无统计学意义。3．0％硅烷偶联剂处理组断裂面的扫描电镜照片显示晶须与树脂间的结合良好。结论：硅烷偶联剂KH-570能够增强钛酸钾晶须和树脂间的界面结合强度,但其太多太少均会造成界面结合强度都会下降,本试验KH-570的用量3％时,增强效果最好。     

钛酸钾晶须的填充量对其增强牙用复合树脂抗弯强度的影响

目的：研究钛酸钾晶须填充量对于其增强牙用复合树脂抗弯强度的影响。方法：以3％硅烷偶联剂修饰钛酸钾晶须,修饰后晶须按照40％、50％、60％、70％、75％的填充量分别与树脂基质通过手工搅拌的方式进行混合,合成五组复合树脂并制作出标准试件,然后进行三点弯曲测试及断面的电镜扫描观察。结果：五组的抗弯强度分别是（109．85±15．25）MPa、（133．50±21．66）MPa、（145．30±19．63）MPa、（112．15±11．04）MPa、（112．75±8．73）MPa。当填充量为60％时复合树脂的抗弯强度达到最大。利用SAS统计软件对五组结果进行均数间的Tukey检验可知,60％组与40％、70％、75％组的抗弯强度在α=0．01水平上具有显著性差异,40％、50％、70％、75％四组间抗弯强度在α=0．05水平上差异不显著。断面的电镜扫描可见40％、50％、60％组中晶须均匀分散于树脂基质中,并且结合良好。结论：钛酸钾晶须可以提高复合材料的强度,但过多或过少都不能达到最佳的效果。     

添加不同抗菌剂的纳米增强义齿基托树脂对变形链球菌黏附性能的影响

目的 研究添加不同抗菌剂的纳米增强聚甲基丙烯酸甲酯(PMMA)基托树脂对变形链球菌黏附性能的影响.方法 将二氧化钛(TiO2)、载银二氧化钛(Ag/TiO2)、载银磷酸锆(Ag/ZrP)和四针状氧化锌晶须(T-ZnOw)均按照质量比3％分别与纳米ZrO2颗粒-硼酸铝晶须(alumina borate whiskers,ABW)/PMMA混合,合成复合材料,未添加抗菌剂的作为对照组,共5组.制作试验标准试件,进行表面粗糙度及变形链球菌黏附性能测试.采用SPSS13.0统计分析软件对数据进行分析,组间比较采用SNK检验.结果 当添加抗菌成分量均为3％时,添加载银二氧化钛组的表面粗糙度值最高(P＜0.05),载银二氧化钛组和载银磷酸锆组的细菌黏附量显著高于对照组(P＜0.05),而二氧化钛组和四针状氧化锌晶须组的细菌黏附量低于对照组(P＜0.05).结论 载银二氧化钛及载银磷酸锆可提高纳米增强PMMA义齿基托树脂表面的变形链球菌黏附.     

钛酸酯偶联剂改性纳米SiO2对树脂基托力学性能的影响

目的 探讨钛酸酯偶联剂改性纳米SiO2对PMMA机械性能的影响.方法 使用钛酸酯偶联剂对纳米SiO2进行表面改性,将处理后的纳米SiO2按1％、2％、3％、4％、5％添加量与PMMA混合后制作标准模件,未经处理的为对照组,对所做试件进行三点弯曲实验、硬度及摩擦磨耗测试.结果 添加经钛酸酯偶联改性的纳米SiO2的树脂基托的力学性能有所提高.添加量为3％时挠曲强度(74.07 ±0.23)、硬度(195.95±0.53)值均高于对照组挠曲强度(70.62±0.30)、硬度(191.54 ±0.42);磨耗值(16.02±0.51)小于对照组(20.85±0.07)(P＜0.05).结论 经钛酸酯偶联剂改性的纳米SiO2可以提高树脂基托的力学性能,最佳添加量为3％.     

钛酸钾晶须增强的复合树脂与两种常用复合树脂的抗弯强度的比较

目的：比较钛酸钾晶须增强的复合树脂与两种常用复合树脂的抗弯强度。方法：以3%硅烷偶联剂处理的钛酸钾晶须按照60%填充量与树脂基质混合,合成热固型和化学固化型两种复合树脂。参照ISO-10477标准,将这两种复合树脂以及临床上常用的两种复合树脂Artglass、Z250制成标准试件,进行三点弯曲测试,并结合显微镜形貌观察,对钛酸钾晶须的增强效果进行比较研究。结果：Z250、化学固化组、热固化组、Artglass的抗弯强度分别是（112.86±13.47）MPa、（102.06±9.36MPa、（123.90±15.90）MPa、（90.60±13.35）MPa。热固化组的抗弯强度显著高于Artglass组。化学固化组的抗弯强度与Z250的抗弯强度相当,低于热固化组。钛酸钾晶须和树脂基质结合良好,能有效阻止微裂纹的形成和扩展。结论：经钛酸钾晶须增强的热固化型复合树脂,其抗弯强度高于其它两种常用的牙用复合树脂。     

热处理时间对钛酸钾晶须增强牙用复合树脂的抗弯强度的影响

目的：研究不同热处理时间对钛酸钾晶须增强的复合树脂抗弯强度的影响。方法：将3%硅烷偶联剂处理过的钛酸钾晶须按照60%质量分数的填充量与树脂基质手工搅拌混合后制备复合树脂三点弯曲测试标准试件四组,每组6个。四组标准试件分别经120℃热处理30min、45min、1h、2h后按照ISO-10477的标准进行三点弯曲测试。结果：热处理时间1h的复合树脂抗弯强度（123.90±15.90）MPa明显高于热处理时间为30min时的抗弯强度（98.82±15.84）MPa。结论：钛酸钾晶须增强复合树脂经120℃热处理30min-1h时,随着热处理时间的增加,抗弯强度逐渐增大。     

硅烷偶联剂用量对硼酸铝晶须增强树脂挠曲强度的影响

目的:评价硅烷偶联剂用量对硼酸铝晶须增强树脂挠曲强度的影响。方法:使用0%、1%、2%、3%、4%质量分数的Z-6030对硼酸铝晶须进行表面处理;将处理过的晶须和树脂基质按一定的配方合成5组热固化型复合树脂,每组6个试件,在120℃的烘箱内固化1 h后,按ISO-4049标准进行三点弯曲测试。每组随机选1个试件,进行断面扫描电镜观察。采用SAS 9.2软件包对结果进行均数间两两比较。结果:硅烷偶联剂用量为2%质量分数时,增强树脂的挠曲强度（117.93±11.9）MPa最高,与其余4组差异显著。结论:硅烷偶联剂的用量对晶须的增强效果有显著影响,过多或过少均会降低复合树脂的挠曲强度。     

Whisker-reinforced heat-cured dental resin composites: effects of filler level and heat-cure temperature and time

Currently available dental resin composites are inadequate for use in large stress-bearing crown and multiple-unit restorations. The aim of this study was to reinforce heat-cured composites with ceramic whiskers. It was hypothesized that whiskers substantially strengthen heat-cured composites. It was further hypothesized that whisker filler level and heat-cure temperature and time significantly influence composite properties. Silica particles were fused onto the whiskers to facilitate silanization and to roughen the whiskers for improved retention in the matrix. The whisker filler mass fraction was varied from 0% to 79%, the heat-cure temperature from 80 degrees C to 180 degrees C, and cure time from 10 min to 24 hrs. Flexural strength, work-of-fracture, and fracture toughness of the composites were measured, and specimen fracture surfaces were examined with scanning electron microscopy. Filler level had a significant effect on composite properties. The whisker composite with 70% filler level had a flexural strength in MPa (mean +/- SD; n = 6) of 248 +/- 23, significantly higher than 120 +/- 16 of an inlay/onlay composite control and 123 +/- 21 of a prosthetic composite control (Tukey's multiple comparison test; family confidence coefficient = 0.95). Heat-cure time also played a significant role. At 120 degrees C, the strength of composite cured for 10 min was 178 +/- 17, lower than 236 +/- 14 of composite cured for 3 hrs. The strength of whisker composite did not degrade after water-aging for 100 d. In conclusion, heat-cured composites were substantially reinforced with whiskers. The reinforcement mechanisms appeared to be whiskers bridging and resisting cracks. The strength and fracture toughness of whisker composite were nearly twice those of currently available inlay/onlay and prosthetic composites.     

Single-crystalline ceramic whisker-reinforced carboxylic acid-resin composites with fluoride release

Currently available glass-ionomer, resin-modified glass-ionomer, and compomer materials have relatively low strength and toughness and, therefore, are inadequate for use in large stress-bearing posterior restorations. In the present study, ceramic single-crystalline whiskers were mixed with fluorosilicate glass particles and used as fillers to reinforce experimental carboxylic acid-resin composites. The carboxylic acid was a monofunctional methacryloxyethyl phthalate (MEP). Five mass fractions of whisker/(whisker + fluorosilicate glass), and corresponding resin (resin + MEP), were evaluated. Four control materials were also tested for comparison: a glass ionomer, a resin-modified glass ionomer, a compomer, and a hybrid composite resin. Flexural specimens were fabricated to measure the flexural strength, elastic modulus, and work-of-fracture (an indication of toughness). Fluoride release was measured by using a fluoride ion selective electrode. The properties of whisker composites depended on the whisker/(whisker + fluorosilicate glass) mass fraction. At a mass fraction of 0.8, the whisker composite had a flexural strength in MPa (mean +/- sd; n = 6) of 150 +/- 16, significantly higher than that of a glass ionomer (15 +/- 7) or a compomer control (89 +/- 18) (Tukey's multiple comparison test; family confidence coefficient = 0.95). Depending on the ratio of whisker:fluorosilicate glass, the whisker composites had a cumulative fluoride release up to 60% of that of a traditional glass ionomer. To conclude, combining ceramic whiskers and fluorosilicate glass in a carboxylic acid-resin matrix can result in fluoride-releasing composites with significantly improved mechanical properties.     

Dental resin composites containing ceramic whiskers and precured glass ionomer particles.

OBJECTIVES: Glass ionomer, resin-modified glass ionomer, and compomer materials are susceptible to brittle fracture and are inadequate for use in large stress-bearing posterior restorations. The aim of this study was to use ceramic single crystal whiskers to reinforce composites formulated with precured glass ionomer, and to examine the effects of whisker-to-precured glass ionomer mass ratio on mechanical properties, fluoride release, and polishability of the composites. METHODS: Silica particles were fused onto silicon nitride whiskers to facilitate silanization and to improve whisker retention in the matrix. Hardened glass ionomer was ground into a fine powder, mixed with whiskers, and used as fillers for a dental resin. Four control materials were also tested: a glass ionomer, a resin-modified glass ionomer, a compomer, and a hybrid composite. A three-point flexural test was used to measure flexural strength, modulus, and work-of-fracture. A fluoride ion-selective electrode was used to measure fluoride release. Composite surfaces polished simulating clinical procedures were examined by SEM and profilometry. RESULTS: At whisker/(whisker + precured glass ionomer) mass fractions of 1.0 and 0.91, the whisker composite had a flexural strength in MPa (mean (SD); n = 6) of (196 (10)) and (150 (16)), respectively, compared to (15 (7)) for glass ionomer, (39 (8)) for resin-modified glass ionomer, (89 (18)) for compomer, and (120 (16)) for hybrid composite. The whisker composite had a cumulative fluoride release of nearly 20% of that of the glass ionomer after 90 days. The whisker composites had surface roughness comparable to the hybrid resin composite. SIGNIFICANCE: Composites filled with precured glass ionomer particles and whiskers exhibit moderate fluoride release with improved mechanical properties; the whisker-to-glass ionomer ratio is a key microstructural parameter that controls fluoride release and mechanical properties.     

Three-body wear of dental resin composites reinforced with silica-fused whiskers.

OBJECTIVE: Recent studies used silica-fused whiskers to increase the strength and toughness of resin composites. This study investigated the three-body wear of whisker composites. It was hypothesized that the whisker composites would be more wear resistant than composites reinforced with fine glass particles, and the whisker-to-silica filler ratio would significantly affect wear. METHODS: Silica particles were mixed with silicon nitride whiskers at seven different whisker/(whisker + silica) mass fractions (%): 0, 16.7, 33.3, 50, 66.7, 83.3, and 100. Each mixture was heated at 800 degrees C to fuse the silica particles onto the whiskers. Each powder was then silanized and incorporated into a dental resin to make the wear specimens. A four-station wear machine was used with specimens immersed in a slurry containing polymethyl methacrylate beads, and a steel pin was loaded and rotated against the specimen at a maximum load of 76 N. RESULTS: Whisker-to-silica ratio had significant effects (one-way ANOVA; p < 0.001) on wear. After 4 x 10(5) wear cycles, the whisker composite at whisker/(whisker + silica) of 16.7% had a wear scar diameter (mean +/- sd; n = 6) of (643 +/- 39) microm and a wear depth of (82 +/- 19) microm, significantly less than a wear scar diameter of (1184 +/- 34) microm and a wear depth of (173 +/- 15) microm of a commercial prosthetic composite reinforced with fine glass particles (Tukey's multiple comparison). SEM examination revealed that, instead of whiskers protruding from the worn surface, the whiskers were worn with the composite surface, resulting in relatively smooth wear surfaces. SIGNIFICANCE: Silica-fused whisker reinforcement produced dental resin composites that exhibited high resistance to wear with smooth wear surfaces. These properties, together with the strength and fracture toughness being twice those of current glass particle-reinforced composites, may help extend the use of resin composite to large stress-bearing posterior restorations.     

Dental composite resins containing silica-fused ceramic single-crystalline whiskers with various filler levels.

Currently available direct-filling composite resins are susceptible to fracture and hence are not recommended for use in large stress-bearing posterior restorations involving cusps. The glass fillers in composites provide only limited reinforcement because of the brittleness and low strength of glass. The aim of the present study was to use ceramic single-crystalline whiskers as fillers to reinforce composites, and to investigate the effect of whisker filler level on composite properties. Silica particles were fused onto the whiskers to facilitate silanization and to roughen the whiskers, thereby improving retention in the matrix. The composite flexural strength, elastic modulus, hardness, and degree of polymerization conversion were measured as a function of whisker filler mass fraction, which ranged from 0% to 70%. Selected composites were polished simulating clinical procedures, and the surface roughness was measured with profilometry. The whisker composite with a filler mass fraction of 55% had a flexural strength (mean +/- SD; n = 6) of 196+/-10 MPa, significantly higher than 83+/-14 MPa of a microfill and 120+/-16 MPa of a hybrid composite control (family confidence coefficient = 0.95; Tukey's multiple comparison). The composite modulus and hardness increased monotonically with filler level. The flexural strength first increased, then plateaued with increasing filler level. The degree of conversion decreased with increasing filler level. The whisker composite had a polished surface roughness similar to that of a conventional hybrid composite (p>0.1; Student's t). To conclude, ceramic whisker reinforcement can significantly improve the mechanical properties of composite resins; the whisker filler level plays a key role in determining composite properties; and the reinforcement mechanisms appear to be crack pinning by whiskers and friction from whisker pullout resisting crack propagation.