纳米金刚石改性义齿粘附剂的粘接性能

目的:观察纳米金刚石作为改性功能填料加入到高分子树脂类义齿粘附剂中,对义齿粘附剂粘接性能的影响。方法:以不同比例配方的纳米金刚石作为功能填料,加入到义齿粘附剂中,观察其粘接抗张强度的变化,同时优选出纳米金刚石的最佳配方产物,浸泡在人工唾液后粘接性能的改变。结果:添加比例为0.05wt%、0.1wt%,义齿粘附剂的粘接抗张强度均明显提高,添加比例为0.1wt%时提高最为明显;纳米金刚石偶联剂改性后反而降低粘附剂强度;0.1wt%组浸泡人工唾液20min粘接抗张强度提高最明显。结论:适当比例的纳米金刚石能增加义齿粘附剂的粘接抗张强度,浸泡唾液一定时间后能改善其粘接性能。     

氧化锆和纳米金刚石比例对核树脂挠曲强度的影响

目的 探讨二氧化锆、纳米金刚石比例对核树脂挠曲强度的影响.方法 采用双酚A-甲基丙烯酸缩水甘油酯(Bis-GMA)和二甲基丙烯酸三甘醇酯(TEGDMA)为树脂基质, 钡玻璃粉(BG)为主填料, 选择不同比例的微米或纳米级二氧化锆,纳米金刚石作为功能填料, 采用原位聚合法生成光固化牙科核树脂,万能材料试验机测定其挠曲强度.结果 含60wt%钡玻璃粉、0.2wt%纳米金刚石的树脂中,加入纳米级或微米级的二氧化锆含量分别为2wt%、3.5wt%、5wt%,3.5wt%相应核树脂挠曲强度最高;含70wt%钡玻璃粉、0.1wt%纳米金刚石的树脂中,加入40 nm的二氧化锆含量为0wt%、2wt%、3.5wt%、5wt%,2wt%质量百分比相应核树脂挠曲强度最高.结论 适当比例填料的核树脂挠曲强度能达到相应的国家标准及ISO标准的规定,能满足临床需要.     

表面有机改性纳米SiO_x对A-2186硅橡胶机械性能的影响

目的:研究添加不同浓度的表面改性纳米SiOx对A-2186硅橡胶机械性能的影响。方法:将表面有机改性纳米SiOx分别按照2、4、6wt%的比例加入A-2186硅橡胶,固化后得到3组实验样品,未添加表面有机改性纳米SiOx的A-2186硅橡胶作为对照组。按照ASTM标准制作试件,测试材料的拉伸强度、拉断伸长率、撕裂强度、邵氏A硬度。采用SPSS10.0软件包对数据进行统计学分析。结果:添加表面有机改性纳米SiOx后,A-2186硅橡胶的拉伸强度自(6.16±0.27)MPa显著下降(P<0.001)。表面有机改性纳米SiOx添加量为2wt%时,其拉断伸长率(292.20±6.26)%较对照组(314.40±8.05)%下降,无统计学差异(P=0.068)。其余各实验组与对照组相比,差异有统计学意义。表面有机改性纳米SiOx加入量为2、4wt%时,A-2186硅橡胶的撕裂强度(12.50±0.96)kN/m分别提高至(21.96±1.02)kN/m、(18.22±1.07)kN/m,均较对照组有统计学差异(P<0.001);其中,2wt%组高于4wt%组,两者差异显著(P<0.001)。加入表面有机改性纳米SiO...     

添加表面改性纳米氧化锌对颌面赝复硅橡胶机械性能影响的研究

目的:研究添加不同质量比的表面改性纳米氧化锌(ZnO)对颌面赝复硅橡胶A-2186机械性能的影响。方法:将经过表面改性的纳米ZnO分别按0.0wt%、0.5wt%、1.0wt%、1.5wt%、2.0wt%、2.5wt%和3.0wt%加入A-2186硅橡胶中,依据ASTM相关标准制作试件并测定7组硅橡胶的拉伸强度、扯断伸长率、撕裂强度及邵氏A硬度,扫描电镜观察试样断面情况,结果进行统计学分析。结果:表面改性纳米ZnO添加量在2.0wt%,2.5wt%,3.0wt%质量比的硅橡胶机械性能均与对照组具有统计学意义;在0.5wt%,1.0wt%,1.5wt%添加量时硅橡胶机械性能与对照组无统计学差异。随表面改性纳米ZnO添加量的增加,A-2186硅橡胶的拉伸强度、扯断伸长率、撕裂强度呈现先增加,后降低的趋势,邵氏A硬度逐渐增大。当纳米ZnO添加量达到胶料的2.0wt%时,扫描电镜观察纳米ZnO分散良好,未发生团聚,此时A-2186硅橡胶的机械性能综合评价为最优:邵氏A硬度为31.00±0.61(U),扯断伸长率为611.00±7.42(%),拉伸强度为6.52±0.45(MPa),撕裂强度为16.11±0.42(KN/m)。结论:表面有机改性纳米ZnO添加量<1.5%时对颌面赝复硅橡胶机械性能无影响,添加量为1.5wt%～3.0wt%时对颌面赝复硅橡胶机械性能均有改善,当添加量为2.0wt%时,对A-2186硅橡胶机械性能的改善为最优。     

纳米金刚石填料对复合树脂耐磨性能及挠曲强度的影响

目的观察纳米金刚石填料对复合树脂耐磨性能、挠曲强度的影响,探索纳米金刚石填料的最佳比例。方法按不同比例将纳米金刚石添加到复合树脂中,检测其磨耗率、挠曲强度。结果添加比例为0.005%、1.000%组磨耗率、挠曲强度无明显变化。添加比例在0.020%～0.600%之间耐磨性能、挠曲强度明显提高,比例为0.600%时耐磨性能提高最为明显,添加比例为0.300%时挠曲强度提高最为明显。结论适当比例的纳米金刚石填料可以提高复合树脂的耐磨性能和挠曲强度。     

纳米非晶金刚石膜改善义齿基托表面变形链球菌黏附量的研究

目的:观察比较义齿基托材料镀用纳米非晶金刚石薄膜前后,表面变形链球菌黏附量变化情况,探索纳米非晶金刚石薄膜镀用义齿树脂基托表面后的抗菌可能性。方法:采用热凝牙托材料制作30mm×10mm×2mm标准试件30个。按不同粗糙度(280目、600目、1200目)分成3组,每组10个。相同粗糙度的10个试件再分成2组,每组5个,一组试件双面镀用纳米非晶金刚石薄膜作为实验组,一组不作处理作为对照组。结果:3组不同粗糙度试件实验组及对照组均存在变形链球菌黏附,实验组少于对照组,两者差异有显著性(1200目P<0.05;600及280目P<0.01);不论实验组还是对照组试件表面变形链球菌黏附量均随粗糙度增大而增多(P<0.05),实验组增多趋势相对较小。结论:纳米非晶金刚石薄膜能够改善义齿树脂基托表面的变形链球菌黏附量,具有部分抑菌功能。     

纳米金刚石填料对光固化窝沟封闭剂黏结剪切强度和表面显微硬度的影响

目的：观察纳米金刚石填料对窝沟封闭剂黏结剪切强度和表面显微硬度的影响，并比较其与气相二氧化硅之间的差别。方法：按不同比例将纳米金刚石添加到窝沟封闭剂中，检测其黏结剪切强度、表面显微硬度。结果：添加纳米金刚石后窝沟封闭剂的表面显微硬度明显提高，黏结剪切强度不受影响。添加5、10、20、40g／L的纳米金刚石比添加20g／L气相二氧化硅能获得更高的黏结剪切强度和表面显微硬度。结论：适当比例的纳米金刚石填料可以提高窝沟封闭剂的机械性能。     

纳米增韧牙科复合树脂的研究

目的：研究纳米二氧化锆、纳米金刚石为功能填料加入到以钡玻璃粉为主填料的光固化牙科复合树脂中,观察树脂挠曲强度的变化.方法：采用双酚A-甲基丙烯酸缩水甘油酯（Bis-GMA）和二甲基丙烯酸三甘醇酯（TEGDMA）为树脂基质,钡玻璃粉（BG）为主填料,选择纳米二氧化锆,纳米金刚石为功能填料,采用原位聚合法生成光固化牙科树脂,万能材料试验机测试其挠曲强度.结果：纳米二氧化锆和纳米金刚石之间不存在交互效应.不同浓度纳米二氧化锆之间有显著差异,不含纳米二氧化锆的树脂挠曲强度显著高于含5%纳米二氧化锆树脂的挠曲强度.不同浓度纳米金刚石之间有显著差异,含0.2%纳米金刚石的树脂挠曲强度显著高于含0.1%纳米金刚石树脂的挠曲强度.结论：含5%纳米二氧化锆、0.2%纳米金刚石的复合树脂颜色美观,其挠曲强度能达到相应的国家标准及ISO标准,能满足临床需要.     

改性纳米氧化铈对义齿树脂基托机械性能的影响

目的:研究经硬脂酸改性后的纳米CeO₂对义齿树脂基托机械性能的影响。方法:将改性纳米颗粒按照质量比分别为1%、2%、3%、4%和5%的添加量添加到义齿基托材料(PMMA)的单体中,制成不同浓度的纳米齿复合材料,制成标准试件。对每组试件冲击强度,弯曲强度等指标进行检测,并与未添加纳米颗粒组比较,将最终数据进行统计分析。结果:经硬脂酸改性后的纳米氧化铈能够提高树脂基托的机械性能,所测试指标都呈现先增大后减小的趋势。其中添加比例为3%时纳米复合材料的综合性能达到最佳状态,其冲击强度、弯曲强度和弯曲模量分别为(4.186±0.149) J/cm²、(88.865±2.345) MPa和(1.539±0.096) GPa(P<0.05)。结论:在义齿基托材料单体中加入不同浓度的纳米氧化铈颗粒可以提高传统义齿基托的冲击强度,弯曲强度等机械性能,从而可以获得品质优良的纳米义齿复合材料。     

纳米金刚石填料对光固化窝沟封闭剂渗透性的影响

目的：观察纳米金刚石填料对光固化窝沟封闭剂渗透性的影响，并与气相二氧化硅作比较。方法：在光固化窝沟封闭剂中加入10、20g／L的纳米金刚石和20g／L的气相二氧化硅，检测其渗透性的变化，并对黏结界面作形态学观察。结果：添加10、20g／L的纳米金刚石后，窝沟封闭剂的渗透性不受影响，而添加20g／L的气相二氧化硅后渗透性显著降低，形态学观察见树脂突形成不良。结论：适当比例的纳米金刚石填料对窝沟封闭剂的渗诱件无明显影响．效果优于气相二氧化硅。     

纳米金刚石改性核树脂的机械及固化性能

目的以纳米金刚石（ UFD）为填料加入到自行合成的光固化核树脂中,测试核树脂的性能变化。方法将不同含量的钡玻璃粉填料和UFD加入到树脂基质中制得6组光固化核树脂,分别测试它们的挠曲强度、维氏显微硬度和光固化深度,使用单因素方差分析法对挠曲强度、维氏显微硬度值的测量结果进行统计学分析。结果仅加质量分数为0.2%硅烷化处理的UFD即可使钡玻璃含量分别为60%和70%的两种光固化核树脂的挠曲强度分别提高34%和21%,而维氏显微硬度分别增加23%和30%;同时核树脂的固化深度均超过2 mm,符合相应的国际标准要求。但是UFD会对核树脂的颜色产生一定影响。结论微量UFD的加入能显著改善树脂的机械性能,同时又不影响材料的固化性能,但是对树脂颜色的影响需进一步改善。     

Radiopaque dental adhesives: dispersion of flame-made Ta2O5/SiO2 nanoparticles in methacrylic matrices

OBJECTIVES: Radiopaque dental adhesive (DA) of low viscosity were made by forming stable suspensions of weakly agglomerated Ta2O5/SiO2 nanoparticles with primary particle size of about 10nm. METHODS: The particles were prepared by one-step flame-spray pyrolysis. Particles were functionalized with gamma-methacryloxypropyltrimethoxysilane (MPS) and dispersed in a methacrylic monomer matrix by centrifugal mixing and ultrasonication. Particle size distributions were analyzed by X-ray disc centrifugation of suspensions and TEM analysis of cured sample composites, while average primary particle size was obtained by N2 adsorption and X-ray diffraction. RESULTS: The dispersion method affected the aggregate size distribution of both untreated and surface functionalized particles in these suspensions. The influence of particle content on suspension viscosity, aggregate size distribution and that of Ta2O5 content on radiopacity was investigated. The shear bond strength of such radiopaque particle-containing adhesives on enamel and dentin was comparable to that of the particle-free reference adhesive. CONCLUSIONS: Flame-made Ta2O5/SiO2 nanoparticles can be introduced readily into dental adhesives as they form quite stable suspensions. Viscosity stayed low even after adding radiopaque particles up to 20 wt.%. The resulting composites had radiopacity comparable to that of enamel facilitating their distinction from marginal gaps. Bond strength was not significantly influenced by the presence of particles in the adhesive.     

Use of (meth)acrylamides as alternative monomers in dental adhesive systems

Objectives: Methacrylamides are proposed as components for dental adhesive systems with enhanced resistance to hydrolytic and enzymatic degradation. The specific objective of this study was to evaluate the polymerization kinetics, water sorption and solubility, pH-derived degradation and microtensile bond strength of various monofunctional acrylamides and meth(acrylamides) when copolymerized with dimethacrylates. Methods: Base monomers were added at 60?wt%, and included either BisGMA or UDMA. Monofunctional monomers were added at 40?wt%, including one (meth)acrylate as the control, two secondary methacrylamides and two tertiary acrylamides. DMPA (0.2?wt%) and DPI-PF6 (0.4?wt%)/BHT (0.1?wt%) were added as initiators/inhibitor. Polymerization kinetics wwere followed with near-IR spectroscopy in real time. Water sorption (WS) and solubility (SL) were measured following ISO 4049. Monomer degradation at different pH levels was assessed with ¹H NMR. Microtensile bond strength (MTBS) was assessed in caries-free human third molars 48?h and 3 weeks after restorations were placed using solvated BisGMA-based adhesives (40?vol% ethanol). Data were analyzed with one-way ANOVA/Tukey’s test (α?=?0.05). Results: As expected, rate of polymerization and final degree of conversion (DC) were higher for the acryl versions of each monomer, and decreased with increasing steric hindrance around the vinyl group for each molecule. In general, UDMA copolymerizations were more rapid and extensive than for BisGMA, but this was dependent upon the specific monofunctional monomer added. WS/SL were in general higher for the (meth)acrylamides compared to the (meth)acrylates, except for the tertiary acrylamide, which showed the lowest values. One of the secondary methacrylamides was significantly more stable than the methacrylate control, but the alpha substitutions decreased stability to degradation in acid pH. MTBS in general was higher for the (meth)acrylates. While for all materials the MTBS values at 3 weeks decreased in relation to the 24?h results, the tertiary acrylamide showed no reduction in bond strength. Significance: This study highlights the importance of considering steric and electronic factors when designing monomers for applications where rapid polymerizations are needed, especially when co-polymerizations with other base monomers are required to balance mechanical properties, as is the case with dental adhesives. The results of this investigation will be used to design fully formulated adhesives to be tested in clinically-relevant conditions.     

氧化钾的含量对牙科微晶玻璃析晶性能的影响

目的 研究氧化钾（K2O）的含量对牙科微晶玻璃析晶性能的影响。方法 在Li2O-SiO2-Al2O3-P2O5-ZnO体系的基质玻璃中添加不同含量的K2O,根据差热分析（DTA）曲线确定微晶玻璃的热处理制度,采用X射线衍射分析和扫描电子显微镜（SEM）观测来比较不同的K2O含量对牙科Li2O-SiO2-Al2O3-P2O5-ZnO体系微晶玻璃析晶成分和显微结构的影响。结果 K2O的引入有助于降低玻璃基体的粘度,促进基质玻璃的析晶。在基质玻璃中添加5.3 wt%的K2O可以使玻璃在热处理后析出较多的二硅酸锂晶体,晶体呈板条状,长度约为4 μm,在玻璃基质中分布均匀。 结论 添加一定量的K2O有助于提高牙科Li2O-SiO2-Al2O3-P2O5-ZnO体系微晶玻璃的析晶性能。     

Methacrylate-functionalized proanthocyanidins as novel polymerizable collagen cross-linkers — Part 2: Effects on polymerization,microhardness and leaching of adhesives

ObjectiveThe aim of the study was to investigate the effects of a novel polymerizable collagen cross-linker methacrylate-functionalized proanthocyanidins (MAPA) on the polymerization, microhardness and leaching of a HEMA-based experimental dental adhesive system.MethodsThree MAPAs were synthesized using different methacrylate (MA) to proanthocyanidins (PA) feeding ratios of 1:2, 1:1, and 2:1 to obtain MAPA-1, MAPA-2, and MAPA-3, respectively. The resulting three MAPAs and PA were added to an experimental adhesive formulated with HEMA and a tri-component photoinitiator system (0.5 wt% CQ/EDMAB/DPIHP) at 1%, 5% and 10% MAPA or PA concentrations (wt%). The adhesive polymerization kinetics was measured continuously in real-time for 10 min using a Fourier-transform infrared spectroscopy (FTIR) with an attenuated total reflectance (ATR) accessory. Degree of conversion (DC) and Vickers microhardness (MH) of cured adhesives were measured at 72 h post-cure. The leaching of cured adhesives in DI water was monitored using UV–vis spectrophotometer. Statistical analysis was performed using one-way and two-way ANOVA, Tukey’s (p < 0.05).ResultsThe adhesive formulations with 1%, 5% and 10% MAPAs-1, -2, -3 all generated higher rate of polymerization and 10-min DC than the formulations with PA at the same concentrations. At 72 h post-cure, the adhesive formulation with 5% MAPA-2 exhibited significantly higher DC (99.40%) and more than doubled MH (18.93) values than the formulation with 5% PA (DC = 89.47%, MH = 8.41) and the control (DC = 95.46%, MH = 9.33). Moreover, the cured adhesive with 5% MAPA-2 demonstrated significantly reduced PA leaching in comparison with cured adhesive with 5% PA.SignificanceSynthesized MAPA is a novel class of polymerizable collagen cross-linker that not only stabilizes dentin collagen via its PA component, but also improves polymerization, mechanical properties and stability of HEMA-based adhesives via its MA component. By inheriting the benefit while overcoming the drawback of PA, MAPA offers a revolutionary solution for improved bond-strength and longevity of dental restorations.     

A review of the developments of multi-purpose primers and adhesives comprising novel dithiooctanoate monomers and phosphonic acid monomers

This paper reviews the developments of dithiooctanoate monomers and acidic adhesive monomers, and their roles in multi-purpose primers and adhesives in promoting adhesion to multiple substrate materials. Novel dithiooctanoate monomers exhibited excellent bonding to precious metals and alloys when compared against conventional sulfur-containing monomers. Newly developed phosphonic acid monomers, endowed with a water-soluble nature, enabled sufficient demineralization of dental hard tissues and thus improved bonding to both ground enamel and dentin. The optimal combination for bonding to dental hard tissues and precious and non-precious metals and alloys was 5.0 wt% 10-methacryloyloxydecyl 6,8-dithiooctanoate (10-MDDT) and 1.0 wt% 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA). For bonding to dental porcelain, alumina, zirconia, and gold (Au) alloy, a ternary combination of silane coupling agent, acidic adhesive monomers, and dithiooctanoate monomers seemed promising. The latest development was a single-bottle, multi-purpose, self-etching adhesive which contained only acidic adhesive monomers and dithiooctanoate monomers but which produced strong adhesion to ground enamel and dentin, sandblasted zirconia, and Au alloy.     

Optimizing filler content in an adhesive system containing pre-reacted glass-ionomer fillers.

OBJECTIVES: (1) To evaluate the optimal concentration of the calcium type pre-reacted glass-ionomer (PRG-Ca) fillers in experimental light-activated adhesives for bonding to tooth substrates and fluoride release; (2) to evaluate the polymerization reactivity of these experimental filled adhesives; and (3) to examine the ultrastructure of the resin-dentin interface bonded with the commercial version of this self-etching adhesive (Imperva Fluoro Bond, Shofu Inc., Kyoto, Japan). MATERIALS AND METHODS: PRG-Ca fillers were prepared from the acid-base reaction of calcium type fluoroaluminosilicate glass with poly(acrylic acid) in water. Different experimental light-cured adhesives were prepared, with 0-57wt% PRG-Ca fillers and 3wt% aerosil silica incorporated in a resin matrix. Twenty-four hours shear bond strengths to bovine enamel and dentin were assessed using the adhesive with/or without accelerated aging. The cumulative amount of fluoride released from the cured adhesives and differential scanning calorimetry (DSC) measurements were also conducted. 180-grit SiC paper polished human dentin disks were treated with Imperva Fluoro Bond that contains 17wt% PRG-Ca fillers and prepared for TEM examination. RESULTS: Increase in PRG-Ca filler content of experimental adhesives was highly correlated with the decrease in bond strengths to dentin (r=-0.96 to -0.99), the increase in cumulative fluoride release, (r=0.97) and the decrease in polymerization energy (cal/g) of the adhesives (r=-0.99) (p<0.001). A PRG-Ca content of 17wt% provided optimal bond strength to enamel and dentin after accelerated aging and fluoride release. TEM showed that salt-like matrices were present around the hydrogels and remnant glass cores of the PRG-Ca fillers. The commercial self-etching primer completely dissolved the smear layer and formed 2 micrometer thick hybrid layers in intact dentin. SIGNIFICANCE: The use of silanized PRG-Ca fillers provides good adhesion and a source of fluoride release in a commercially available self-etching adhesive system.     

Niobium pentoxide phosphate invert glass as a mineralizing agent in an experimental orthodontic adhesive

Objective:The aim of this study was to develop an experimental orthodontic adhesive and evaluate how adding phosphate invert glass containing niobium pentoxide (PIG-Nb) affected the adhesive''s properties.Material and Methods:PIG-Nb was added at 1, 2.5, and 5 wt% to experimental adhesive (75 wt% bisphenol A methacrylate [BisGMA], 25 wt% triethylene glycol dimethacrylate [TEGDMA], 5 wt% colloidal silica and photoinitiator system). The adhesives were evaluated for mineral deposition, degree of conversion (DC), softening solvent by Knoop microhardness (KNH) variation, pH changes, and shear bond strength (SBS). One-way analysis of variance (ANOVA) (DC and ΔKHN%), two-way ANOVA (SBS), repeated measures ANOVA (pH), and paired test (KNH1 and KNH2) were used at a significance level of P < .05.Results:Adding PIG-Nb to orthodontic adhesives induced deposition on its surface associated with a constant neutral pH. The SBS increased after immersion in artificial saliva, and the PIG-Nb5 exhibited less softening.Conclusion:The addition of PIG-Nb into orthodontic adhesives induced mineral deposition. Experimental orthodontic adhesive containing 5% wt of PIG-Nb exhibited increased mineral deposition and suitable properties for orthodontic applications.