12种非金属核材料的弯曲性能研究

目的：研究临床常用的12种非金属制核材料的弯曲性能,为临床选择制核材料提供依据。方法：根据制核材料的种类分12组,依据ISO4049-2000标准,按照各种制核材料产品使用说明分别制作规格为：25mm×2mm×2mm的标准试件,在万能力学试验机上测试弯曲性能。结果：不同种类制核材料的弯曲性能有显著性差异（P〈0.05）,其中树脂类制核材料的弯曲性能优于玻璃离子类材料。结论：不同种类制核材料的弯曲性能不同,临床使用时应根据具体情况选用合适的材料。     

POSS填料对复合树脂弯曲强度和抗压强度的影响

目的：比较POSS复合树脂和三种临床常用复合树脂/聚合体弯曲强度和抗压强度,为POSS复合树脂的临床应用提供参考依据。方法：采用Zwick电子万能试验机分别测试试样的弯曲强度和抗压强度,以l.0mm/min的加载速度垂直加压直至试样破坏,记录破坏时的载荷,测试结果用SPSS16.0软件进行多样本均数方差分析（F检验）和SNK-q检验。结果：弯曲强度测试结果：FiltekTM Z250组最高,与其他三组间均有统计学差异;BeautifilII组好于POSS组和SureFil组（P〈0.05）;POSS组与SureFil组间无显著性差异（P〉0.05）。抗压强度测试结果：FiltekTM Z250组最高,与其他三组间均有统计学差异;SureFil组好于POSS组和BeautifilII组（P〈0.05）;POSS组和BeautifilII组间无显著性差异（P〉0.05）。结论：POSS复合树脂的弯曲强度和抗压强度可以满足临床应用需要。     

复合树脂桩核材料的临床应用及疗效观察

目的 复合树脂桩核材料的临床应用及初步探讨。方法 对５３例患牙用复合树脂桩核材料和预面冠固定修复并进行３个月至１年的追踪观察。结果 ５０例使用良好,未见异常,３例冠与桩核齐牙颈部折断,基牙牙根未劈裂。结论 复合树脂桩核材料的弹性模量更接近牙本质的弹性模量,是一种较好的桩核修复材料。     

不同复合树脂桩核材料与纤维桩微拉伸强度的对照研究

目的:比较3种复合树脂核材料与玻璃纤维桩的微拉伸粘接强度.方法:21个DT Light玻璃纤维桩随机分为3组(n=7),分别用3种不同的复合树脂核材料DC Core Automix(DC)、LuxaCore(Lc)、卡瑞斯玛前后牙通用复合树脂(CS)粘固制成桩核样本,制备好的样本切割成截面为1 mm×1 mm的条状试件用于微拉伸强度测试.结果:DC与纤维桩的微拉伸粘结强度显著高于LC和CS(P＜0.05),LC和CS与纤维桩的微拉伸粘结强度没有显著性差异(P＞0.05).结论:DC Core Automix与玻璃纤维桩的粘结性能优于另两种复合树脂核材料.     

水的含量对硼酸铝晶须-二氧化硅熔附体填料复合树脂弯曲性能的影响

目的：研究正硅酸乙酯（TEOS）水解、缩聚过程中水与TEOS的摩尔比对硼酸铝晶须（AlBw）与SiO2熔附体填料复合树脂弯曲性能的影响。方法：采用TEOS溶胶-凝胶法,通过控制水与TEOS的摩尔比,制得不同粒径大小及分布的纳米SiO2,高温烧结使其熔附于AlBw表面,制作试样并测试其弯曲强度和弯曲弹性模量;利用透射电镜（TEM）观察AlBw-SiO2熔附体形貌。结果：水与TEOS摩尔比对牙科复合树脂的弯曲强度有显著性影响,但对弯曲弹性模量无显著性影响。SiO2纳米粒子的粒径大小及分散程度将影响牙科复合树脂的弯曲性能;不同粒径大小的纳米粒子不会影响牙科复合树脂的弯曲弹性模量。M水/TEOS=22时复合树脂的弯曲强度达149.59±12.86Mpa。结论：水与TEOS摩尔比可改善AlBw-SiO2熔附体填料复合树脂的弯曲性能。     

6种复合树脂粘接剂与纤维增强型复合树脂根管桩的粘接强度研究

目的评价6种复合树脂粘接剂与带有半渗透网状复合基质的纤维增强型复合树脂根管桩的粘接强度。方法实验分为6组,分别为纤维增强型复合树脂根管桩和6种复合树脂粘接剂模块,每组7个样本。用粘接树脂活化剂处理各组根管桩表面5min,将粘接剂模块粘接到根管桩表面并固化,37℃下储存各组样本20h后,万能实验机进行剪切粘接强度测定。结果6种不同复合树脂粘接剂与纤维增强型复合树脂根管桩粘接后,各组根管桩表面剪切粘接强度之间的差异无统计学意义（F=2.32,P=0.45）。结论6种复合树脂粘接剂均适用于纤维增强型复合树脂根管桩的粘接。     

预浸润玻璃纤维强化复合树脂的力学性能

大学口腔医院　修复科;2.北京大学口腔医院　材料教研室,北京100081) [摘要]　目的　研究预浸润玻璃纤维对不同复合树脂的强化效果。方法　制作Sinfony和belleGlass两种复合树脂的加入和不加预浸润玻璃纤维的标准试件(25 mm×2 mm×2 mm),于(37±1)℃的蒸馏水环境中保存24 h后,在万能力学试验机上测试弯曲强度和弹性模量。结果　Sinfony复合树脂加入纤维后弯曲强度和弹性模量显著提高,分别为(555·76±67·31)MPa和(12·59±3·06)GPa,较不加玻璃纤维试件平均提高了4·9和2·5倍(P=0);belleGlass复合树脂加入纤维后弹性模量有提高,为(14·10±2·88)Gpa,较不加玻璃纤维试件平均提高了0·9倍(P=0),而弯曲强度提高不明显。结论　预浸润玻璃纤维可以显著提高复合树脂的力学性能,但对不同复合树脂的强化效果有明显差别。     

GIC衬垫对复合树脂粘接强度的影响

本实验应用玻璃离子粘固剂和光敏固化氢氧化钙作衬垫材料，观察其对复合树脂与牙本质间粘接强度的影响。结果表明采用ＧＩＳ衬垫后，能明显增强复合树脂与牙本质间的粘接强度，而光敏固化氢氧化钙反而降低其粘接强度。各组间差异均极显著。采用ＧＩＳ衬垫方法，以距充填体表面０．５毫米组粘接强度最大，明显高于其它组。     

纳米二氧化硅含量对硼酸铝晶须-二氧化硅熔附体填料复合树脂弯曲性能的影响

目的研究正硅酸乙酯（TEOS）水解所得纳米二氧化硅（SiO2）含量对硼酸铝晶须（AlBw）与SiO2熔附体填料复合树脂弯曲性能的影响。方法采用TEOS溶胶－凝胶法制得纳米SiO2,按不同比例通过高温烧结使其熔附于AlBw表面,制作试样并测试其弯曲强度和弯曲弹性模量;利用透射电镜（TEM）观察高温处理过程对晶须表面形态的影响以及不同比例的熔附体形貌。结果AlBw-SiO2熔附体复合填料可显著提高牙科复合树脂的弯曲性能;AlBw和SiO2的质量比为3∶1时牙科复合树脂的弯曲强度达（130.29±8.38）MPa。结论TEOS溶胶－凝胶法水解所得的纳米SiO2含量可改善AlBw-SiO2熔附体填料复合树脂的弯曲性能。     

硫酸钡改性纤维桩与树脂核材料的粘接强度研究

目的:研究硫酸钡改性纤维桩与3种树脂核材料的微拉伸粘接强度.方法:自研制硫酸钡改性玻璃纤维桩(J Fiber-post,JFP)与商品纤维桩(DT Light post,LP)各12根,随机分成3组.桩周分别用2种双固化树脂 Clearfil DC core(CD),Rebilda DC (RD)与光固化树脂/粘接剂:...     

Comparative Evaluation of Compressive Strength and Flexural Strength of Conventional Core Materials with Nanohybrid Composite Resin Core Material an in Vitro Study

Several dental materials have been used for core build-up procedures. Most of these materials were not specifically developed for this purpose, but as a consequence of their properties, have found application in core build-up procedures. Improvements in composites and the development of nanocomposites have led to their use as a core build up material due to their superior mechanical properties, optical properties and ease of handling. However it is not clear if they have better mechanical properties than the conventional core build up materials like amalgam, GIC and dual cure composite core build up material. The strength of the core material is very important and this study was undertaken to compare the mechanical properties of materials used for direct core foundations. The differences between the compressive strength and flexural strength of Filtek Z350 nanocomposite with conventional core build up materials like Amalgam, Vitremer GIC and Fluorocore were tested. Cylindrical plexi glass split molds of dimension 6 ± 1 mm [height] x4 ± 1 mm [diameter] were used to fabricate 15 samples of each core material for testing the compressive strength and rectangular plexi glass split molds of dimension 25 ± 1 mm [length] x 2 ± 1 mm[height] x2 ± 1 mm [width] used for fabricating samples for flexural strength. The samples were stored a water bath at 250 °C for 24 h before testing. The samples were tested using a Universal Instron testing machine. The results of the study showed that Fluorocore had the highest compressive strength and flexural strength followed by Filtek Z350 [nanocomposite] Amalgam had the least flexural strength and Vitremer GIC had the least compressive strength. Thus flurocore and nanocomposite are stronger than other core build up materials and hence should be preferred over other conventional core build up materials in extensively damaged teeth.     

不同晶须及晶须用量对复合树脂力学性能的影响

目的：比较碳化硅晶须（SiCw）、硼酸铝晶须（ABw）、氧化锌晶须（ZnOw）增强复合树脂的弯曲性能,筛选最优配方。方法：测定复合树脂的弯曲强度和弯曲弹性模量：结果：β-SiCw熔附SiO2纳米粒子（β-SiCw／SiO2）、ABw熔附SiO2纳米粒子（ABw／SiO2）、ZnOw（四针状）均可以提高复合树脂的弯曲性能。本实验条件下复合树脂弯曲性能的最佳方案是：填料为ABw／SiO2,用量为60％时。结论：每一种晶须填料均可以提高复合树脂的弯曲强度和弯曲弹性模量,提高的程度与填料的用量相关。     

Flexural Strength of Interim Resin Materials for Fixed Prosthodontics

Purpose: Flexural strength of interim materials is of particular concern with long-span fixed partial dentures (FPDs) or in areas of heavy contact. The purpose of this study was to compare the flexural strength of seven resins used to fabricate interim fixed prostheses.
Materials and Methods: Ten identical 25 × 2 × 2 mm specimens were made from seven interim materials (N = 70) (Trim, Acropars, Protemp 3 Garant, Unifast LC, TempSpan, Tempron, Duralay) according to ADA specification #27. After 14 days' storage in artificial saliva and thermocycling for 2500 cycles (5˚C to 55˚C), a standard three-point bending test was conducted on the specimens with a universal testing machine at a crosshead speed of 0.75 mm/min. The mean values of flexural strength of each interim material were calculated. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U-test, and the significance level was set at α= 0.05.
Results: The lowest and highest flexural strengths were found for Trim from ethyl methacrylate resins and TempSpan from bis-acryl resins, respectively. The mean rank of flexural strength of the studied materials was TempSpan = 66.3, Protemp 3 Garant = 53.4, Tempron = 47.5, Duralay = 38.3, Unifast LC = 24.1, Acropars = 17.9, and Trim = 5.9. There was no significant difference between Tempron and Protemp 3 Garant, but the other resins were significantly different.
Conclusions: Bis-acryl interim materials exhibited higher flexural strength than the methacrylate resins tested in this study. These higher values should be considered in making interim fixed prostheses, especially when long-term use or long-span FPDs are planned.     

The Effect of Eugenol-Containing Temporary Cement on the Bond Strength of Two Resin Composite Core Materials to Dentin

Purpose This study investigated the effect of eugenol-containing temporary cement on the bond strength of two resin composite core materials (FluoroCore and Ti-Core) to dentin. Materials and Methods Dentin was exposed in three groups of extracted teeth (20 specimens each). In group one, dentin was covered with eugenol-containing temporary cement; the second group was covered with eugenol-free temporary cement; and the third group was left uncovered and served as a control group. All specimens were stored for 1 week at 37°C and 100% humidity. The dentin surfaces were cleaned and treated using the GLUMA adhesive system, followed by placement of composite core build-ups. Debonding of the core material was accomplished using the Accuforce Elite test system. Results There was a significant reduction in bond strength for the specimens covered with eugenol temporary cement (p < .0001), but no significant difference was found between the control group and the group treated with eugenol-free temporary cement. Bond strength of the Ti-Core material to dentin was significantly higher than that of FluoroCore (p < .0001). Conclusion Pretreatment of the dentin with eugenol-based temporary cement adversely affects the bond strength of resin composite core material to dentin.     

Comparative Evaluation of Impact and Flexural Strength of Four Commercially Available Flexible Denture Base Materials: An In Vitro Study

Poly-methyl methacrylate is a rigid material. It is generally observed that the impact and flexural strength of this material is not satisfactory and that is reflected in the continuous efforts to improve these mechanical properties. Hence there was a serious need to make another material which could overcome the limitations of the existing materials and could have better properties, like thermoplastic materials. The study was aimed to evaluate and compare the impact strength and the flexural strength of four different flexible denture base materials (thermoplastic denture base resins) with the conventional denture base material (high impact polymethyl-methacrylate). Two, machine made master moulds of metal blocks according to the size of sample holder of the equipment were prepared to test the impact and flexural strength. Total 40 samples, 10 for each group of flexible denture base materials namely: De-flex (Deflex, United Kingdom), Lucitone FRS (Densply, Germany), Valplast (Novoblast, USA), and Bre-flex (Bredent, Germany) in specially designed flask by injection molded process. For different flexible materials, the time, temperature and pressure for injecting the materials were followed as per the manufacturer’s instructions. Total 20 samples for control (Trevelon denture base materials) were prepared by compression moulded process, for each test. ANOVA test was applied to calculate p value. Unpaired t test was applied to calculate t-value. Tukey–Kramer multiple test was provided for comparison between the groups for flexural and impact strength. From the statistical analysis, it was found that, the impact strength of Group III (Valplast) was found to be the highest than all other groups and nearer to the control group. Whereas Group IV (Bre-flex) had the maximum flexural strength. The flexural strength of Group I (De-flex) was lowest than all other groups and nearer to control group. The values were found to be statistically significant but clinically non-significant with the control (p < 0.001). The overall results of the study showed that, Group III (Valplast) had the maximum impact strength and Group I (De-flex) had the lowest flexural strength, whereas Group IV (Bre-flex) had the maximum flexural strength and lowest impact strength.     

纤维增强树脂桩钉与非金属核材料粘结性能的对照研究

目的 :研究纤维增强树脂桩钉 (s -glassfiberreinforcedcomposites,FRC)与 3种核成形材料的粘结性能。方法 :用 3种核成型材料在FRC桩钉上分别制作核桩试件 ,将试件按材料种类和制作方法分成 4组 :A组 :FRC桩钉 +Coreshade(日本松风 ) ;B组 :FRC桩钉 +AB双组分复合树脂 ;C组 :FRC桩钉 +Charisma通用型复合树脂 ;D组 :FRC桩钉 +釉质粘合剂 +Charisma通用型复合树脂。在万能力学试验机上测试桩钉与核的粘结力。结果 :不同的核材料与FRC桩钉的粘结力差异有显著性 (P <0 .0 5 ) ,由大到小的顺序为 :B组 >D组 >C组 >A组。其中B组的粘结力最大 ,为 (345 .0± 2 7.6 )N ,A组的值最低 ,为 (14 4 .7± 9.6 )N。结论 :不同的核材料与FRC桩钉的粘结力不同 ,临床使用FRC桩钉时应选用流动性较好、强度大的树脂类核材料     

Effect of Surface Treatment on the Flexural Strength of Denture Base Resin and Tensile Strength of Autopolymerizing Silicone Based Denture Liner Bonded to Denture Base Resin: An In Vitro Study

Silicone based denture liners are superior to acrylic based denture liners but it has a problem of failure of adhesion with the denture base. To evaluate the effect on the tensile bond strength of silicone based liner and flexural strength of denture base resin when the latter is treated with different chemical etchants prior to the application of the resilient liner. Rectangular specimens of heat cured PMMA (65 × 10 × 3.3 mm³) for flexural strength and (10 × 10 × 40 mm³) for tensile strength were fabricated and divided into four subgroups each. One subgroup of each type acted as a control and the rest were subjected to surface treatment with acetone for 30 s, MMA monomer for 180 s, methylene chloride for 15 s, respectively. Silicone based denture liner was processed between 2 PMMA specimens (10 × 10 × 40 mm³) in the space provided by a spacer, thermocycled (5^–55°C) for 500 cycles and then their tensile strength measurements and flexural strength measurements were done. 180 s of MMA monomer treatment was found to be most effective in improving the bonding between the liner and denture base resin as well as producing the lowest decrease in flexural strength of denture base resin. Chemical treatment of denture base resin improves the bond strength of denture liner but it also decreases the flexural strength of denture base. So careful selection of chemical etchant should be done so as to produce minimum decrease in flexural strength of denture base resin.