树脂—金属界面固位体—88-3型微型固位球的研制

为提高树脂修复体的使用寿命,树脂—金属联合修复体在临床被广泛应用。金属翼板粘结桥、烤塑冠以及许多常规的树脂—金属联合修复体使用年限在一定程度上也取决于树脂—金属界面的连接固位能力——界面结合强度。近10多年来,利用铸造法在金属与树脂结合的表面上(金属的界面上)铸出微型固位球的方法在国外已广泛应用,获得较好的固位效果。为此,我们研制了生产微型固位球的专门设备,并对固位球的效果作了实验测试和临床应用,现简要介绍如下。     

纤维桩的表面处理

关于根管桩材料和设计的研究已日益成熟.纤维桩树脂核修复被公认为具有较好的修复效果,现在的研究主要集中在桩核的粘接固位方面.除了对粘接剂的研究外,纤维桩表面处理是增强界面粘接强度的常用方法之一,它可以促进不同成分之间形成化学和机械固位.对纤维桩的表面处理主要为了增强桩在根管内的固位以及桩与树脂核的粘接.本文就此作一综述.     

两种托槽粘接剂的比较实验和研究

目的：测定树脂和化学固化型玻璃离子托槽粘接剂的抗剪切粘接强度。方法：100颗离体双尖牙被随机分成两组，每组又按照测试时间的不同分成3个亚组。组1、组2分别用京津釉质粘合剂(树脂)、Ketac—Bond(化学固化型玻璃离子粘接结剂)粘接托槽，对所有实验样本进行了抗剪切粘接强度的测试。结果：①树脂和化学固化型玻璃离子的抗剪切粘接强度随时间的增加而增强。②树脂粘接剂的断裂主要发生在釉质—树脂界面，而化学固化型玻璃离子粘接剂的断裂则主要发生在自身内部。结论：树脂型托槽粘接剂固化后24h以内达到临床应用标准，而化学固化型玻璃离子粘接剂在固化后24h以内达不到该标准，不适合于临床应用。     

金属—复合树脂粘接修复中金属粘接面的处理

粘接技术的发展为口腔修复领域提供了一种可供选择的术式，金属—复合树脂粘接修复是其中的一项重要内容。影响其粘接强度的因素很多，除了金属和树脂的种类及性能以外，对金属粘接面的处理是另外一项重要因素。本文就近年来临床上为增加粘接效果而对金属—树脂粘接面的处理方法作一综述。     

针道辅助固位金属翼板粘接桥的临床初步观察

目的 观察针道辅助固位金属翼板粘接桥修复的临床短期效果.方法 对65例牙列缺损患者进行针道辅助固位金属翼板粘接桥修复,随访修复体固位和基牙健康状况.结果 65例患者共制作74件修复体,随访6～34个月,平均12.4个月.3件修复体松动、脱落,脱粘率为4%.基牙牙本质敏感9例(14%).结论 针道辅助固位可显著提高金属翼板粘接桥的短期成功率,获得良好的临床效果.其长期成功率尚需进一步观察.     

光固化冠桥复合树脂的临床应用

本文总结自1986～1987年临床完成的光固化冠桥复合树脂修复体200余例,经过3年临床观察,复查74例,修复体93件,其中20件树脂牙面脱落或折断,失败率为21.5％。金属与树脂的结合方式,48件采用金属珠机械固位,45件采用硅喷涂化学结合。从失败率分析,机械固位优于硅喷涂技术,而且机械固位的方式,不需要特殊的设备,操作简单、省时,但金属与树脂界面的结合力尚不够理想。光固化冠桥复合树脂,对底金属无选择性,聚合作用由光敏固化装置引发,不受操作时间的限制,可任意堆塑、雕刻,操作方法简单、方便,容易掌握,价格较金属烤瓷低廉,便于推广,临床上有一定的实用意义。失败率较高,强度、耐磨性,色泽均不如金属烤瓷修复体,有待进一步研究。同时对修复体设计的形式及操作方法作简单介绍。     

Silicoater MD及Kevloc粘接系统对丙烯酸树脂与钴铬合金粘接强度的研究

金一塑修复体成功与否很大程度取决于树脂—金属界面是否有理想的粘接强度。Silicoater MD和Kevloc是两种含有硅烷偶联剂的粘接系统,可用于提高金—塑界面的粘接性能。本文的目的在于考查表面预处理方法和化学搁置期(chemical shelf life)对Sillcoater MD系统粘接性能的影响,并且比较两种系统粘接后抗剪切强度的差异。     

比较火焰喷灼和水汽清洁崩瓷界面对于修补树脂粘接强度的影响

目的:比较一种新的火焰喷灼清洁崩瓷表面方式与常规水汽清洁方式对于修补树脂/瓷界面粘接强度的影响.方法:制作30个贵、贱金属和金瓷试样,试样表面经过喷砂,氢氟酸酸蚀刻粗化处理.按照瓷修补套装使用说明,在金属和瓷表面涂布,固化瓷修补树脂,并控制树脂厚度为 1.0 mm.试样采用微拉伸试验,记录断裂时最大负荷值,并在20倍体式显微镜下观察断裂面,评价断裂发生的情况.结果:配对 T 检验显示,两种清洁方式对于树脂/瓷和树脂/镍铬合金粘接强度存在显著性差异(P<0.05).使用火焰喷灼清洁能够显著提高修复树脂的粘接强度.对于金合金组,两种清洁方式之间粘接强度不存在统计学差异.两因素方差分析显示粘接界面的组成及其界面清洁方式对于粘接强度都存在显著性影响(P<0.01),两者之间存在交互作用.结论:火焰喷灼清洁方法能够有效提高瓷修复树脂的粘接强度.     

冠桥树脂与金属基底结合部的疲劳性能

我们在扫描电镜下进行金属基底面罩冠、桥树脂的挠曲疲劳测试,同时研究其结合部折裂与扩张的行为。带有固位珠的金属基底树脂罩面的静态折裂应力为100kgf/mm~2,在用粘合剂粘接时,金属基底罩面树脂具有大约36kgf/mm~2应力。而带有固位珠、同时用粘合剂粘接的测试试样在分别低于40％与50％的静态折裂应力的挠曲疲劳应力下、10°循环中未被损坏。在进行疲劳测试前,观察带有固位珠的树脂与金属基底之间的边缘微裂,发现其随循环次数增加而增加,接着试样的折裂从固位珠边缘产生。用粘合剂粘接的试样中,在进行疲劳测试期间观察树脂与金属基底之间的边缘微裂,发现有部分内聚折裂。     

三种树脂固位铸造金属修复体的临床比较

树脂固位的金属修复体按固位体设计分成称为Rochette桥的大孔固位体和称为M(?)yland桥的酸蚀粘接金属微孔固位体。离体试验表明酸蚀粘接金属固位体比大孔固位体有更好的临床性能。本文调查了固化体设计方式对成功率的影响。总计101个铸造金属背粘接桥在93位患者口内达9个月(13岁～78岁,平均31.5岁)。其中8人口内同时使用了两种粘接桥。固位体设计为下述A、B、C三型。A型:有5个直径1mm小孔的有孔金属支架,覆盖基牙的舌面。B型:有5个直径1mm小孔的有孔金属支架,覆盖舌面和近缺牙间隙的部分邻面,并呈齿状边缘。C型:有一个无固位的溢出孔的酸蚀粘接金属支架,覆盖舌面。 A、B型用钴—铬合金,C型用镍—铬合     

A microscopic examination of bond surfaces in failed electrolytically etched cast metal fixed prostheses

The aims of this investigation were to examine the patterns of resin cement failure between debonded electrolytically etched (Maryland) bridge retainers and their respective abutment teeth and to determine if the clinical assessment of bond failure corresponded to the types of failure observed in the scanning electron microscope. Twenty-eight (18 anterior and 10 posterior), debonded bridges were examined. The results indicated that the classification of bond failures at the clinical level did not correspond to the SEM assessments of failure. It appeared from the specimens examined that loss of retention occurred as a result of resin failure within the cement layer close to the enamel-resin interface. Only one metal retainer specimen showed a small area of resin-metal failure. There appeared to be no differences in the patterns of resin failure between anterior and posterior bridges. The observations also indicated that the resin cements used for bridge cementation adhered well to electrolytically etched retainer surfaces.     

Alternative alloys for resin-bonded retainers

Traditionally, resin-bonded fixed partial dentures have been made with nickel-chrome-beryllium alloys and cemented with conventional resin luting cements. However, alternative alloys for resin-bonded retainers offer improved physical and biocompatible properties, and resin-metal bond strengths twice that of traditional methods can be achieved. The superior bonds obtained with etched base metals bonded with adhesive resins and silica-coated alloys bonded with silane-coupling agents make these the most desirable techniques available.     

Bond strengths of resin-bonded metal castings

Composite resin-retained appliances are susceptible to failure at the resin-metal interface. The objective of this study was to evaluate bond strengths of perforated and electrolytically etched framework designs by subjecting them to tensile and shear loading. Shear bond strengths were always higher than tensile bond strengths. Etched castings were consistently stronger than perforated designs. Castings that were both perforated and etched were stronger in tension than all other retentive designs.     

Effects of polymerization shrinkage on the interfacial stress at resin-metal joint in denture-base: a non-linear FE stress analysis.

OBJECTIVES: The purpose of this study was to investigate the effects of polymerization shrinkage on stress at the interface between resin and metal in removable dentures. METHODS: Three-dimensional finite element models of a denture-base were studied, which consisted of acrylic occlusal rims with different heights and metal frameworks. A relaxation modulus of 1.5 GPa for the resin and a Young's modulus of 220 GPa for the metal were used as the material properties. Each model was constrained at the edge of the framework on the palatal vault. Surface-to-surface contact elements were used to calculate the interfacial stress in a direction perpendicular to the bond surface under a linear shrinkage ranging from 0.41 to 0.65%. The principal stress within the resin was also calculated. RESULTS: The maximum interfacial and principal stresses within the denture-base increased with resin shrinkage. Under the lowest linear shrinkage, the mean area percentages in the resin-metal joint that showed interfacial tensile stresses over 10 and 20 MPa were 63.4 and 0%, respectively. While under the highest linear shrinkage, these mean area percentages were 98.8 and 38.1%, respectively. Negligible differences in the stresses were shown by occlusal heights. SIGNIFICANCE: The polymerization shrinkage level has a significant influence on the residual stress at the resin-metal interface. Enhancement of the bond strength on the interface can reduce the failure probability at a resin-metal joint.     

The effect of bead attachment systems on casting patterns and resultant tensile bond strength of composite resin veneer cast restorations.

This study compared the difference in tensile bond strength between the composite resin veneer and the cast Ni-Cr disk when different bead adhesives were used to make the laboratory patterns. Visio-Gem, cyanoacrylate, and shellac were the adhesives tested. Fifty-six composite resin bonded Ni-Cr disks were prepared and tested to tensile failure with the Kemper-Kilian device. All tested samples showed a complex failure pattern. The results showed that the mean tensile bond strength of the cyanoacrylate group was significantly higher than the other two groups. No significant difference in the mean tensile bond strength was observed between the Visio-Gem and shellac groups. The higher tensile bond strength in the cyanoacrylate group is thought to be attributed to the low rheological property of the adhesive that allowed greater exposure of the bead for retention. Using different adhesives in the fabrication of composite resin veneered-castings may affect the bond strength in the composite resin-metal interface.     

Microtensile bond strength of total-etch and self-etching adhesives to caries-affected dentine

OBJECTIVES: To evaluate the microtensile bond strength of total-etch or self-etch adhesives to caries-affected versus normal dentine, and to correlate these bond strengths with DIAGNOdent laser fluorescence and Knoop microhardness (KH) measurements of the substrates. METHODS: Extracted carious human molars were ground to expose flat surfaces where the caries lesion was surrounded by normal dentine. Surfaces were bonded with either Prime & Bond NT, Scotchbond 1, Clearfil SE Bond or Prompt L-Pop, according to manufacturers' recommendations. A crown was built up using resin composite (Tetric Ceram). After storage in water (37 degrees C, 24 h), teeth were vertically serially sectioned into 0.7 mm thick slabs and trimmed to yield 1 mm(2) test area that contained either caries-affected or normal dentine. Samples were tested in tension in an Instron machine at 1 mm/min. The quality of the dentine just beneath each fractured specimen was measured by laser fluorescence and KH. RESULTS: Total-etch adhesives yielded higher bond strengths than self-etching systems. Significantly lower results were obtained with Prompt L-Pop. All the adhesives attained higher strengths in normal than in caries-affected dentine, but the differences were only significant for Prime & Bond NT and Clearfil SE Bond. Higher laser fluorescence values and lower KH (p<0.001) were recorded in caries-affected dentine compared to normal dentine. CONCLUSIONS: The total-etch adhesives evaluated produced higher bond strengths to normal and caries-affected dentine than self-etching systems. Laser fluorescence measurements discriminated caries-affected dentine from normal dentine, and were strongly correlated with KH. However, laser fluorescence and KH did not permit high correlations with resin-dentine bond strengths in caries-affected dentine.     

Measurement of adhesion of endodontic sealers to dentin

The bond strength of root canal sealers to dentin seems to be an important property for maintaining the integrity of the seal of root-canal fillings. In the few studies published, various assessment methods were used so quantitative comparison is not possible. The purpose of this study was to develop an effective and easily reproducible model and to test it with nine contemporary, commercially available endodontic sealers. After slicing off the coronal 2 mm of extracted third molars, the exposed dentin served as test surfaces. The teeth were fixed with plaster in 1-inch phenolic rings. Five-mm long sections of polyethylene tubing, filled with freshly mixed sealer, were placed on the dentin and tested for shearing bond strength after setting. A custom-made holder allowed the rings to be attached to an Instron machine, activated at a cross-arm speed of 0.5 mm/min. The mean bond strength, ranged from 0 to 4.9 MPa. The sealers were ranked and those that did not differ statistically in their bond strength were grouped together. This model provides a simple and reproducible means for measuring the in vitro bond strength of endodontic sealers.     

树脂微拉伸粘结强度测试法的影响因素

目前常用微拉伸强度测试法对树脂的粘结强度进行评估。微拉伸强度测试法较传统的剪切强度测试有许多独特优点,然而该测试法会受到诸多因素的影响,使之不能准确反映树脂与牙体组织之间的粘结强度。这些影响因素主要包括离体牙储存方式、样本预备、不同的粘结系统以及固化方式等,已有学者对其进行了相关研究,该文就其研究成果作一综述。     

A method for bonding to tooth structure using phosphoric acid as a dentin-enamel conditioner

In clinical practice it is difficult to keep acid etchants off the dentinal surface during bonding procedures. If the acid etchant could be used as part of the overall conditioning system, technique sensitivity would be reduced. This paper reports the data obtained with the use of phosphoric acid as a dentin-enamel conditioner in a bonding system developed by the author. In vitro bond strength and microleakage were examined using Dual Cure Scotchbond as a control. In both tests, the experimental group showed statistically significantly better results than did the control. A clinical study of 140 Class II restorations showed no postoperative sensitivity, and all teeth were vital after 18 months.     

Bonding efficacy and side effects of the high purity glyceryl mono-methacrylate

The purpose of this study was to examine the efficacy of experimentally developed high purity glyceryl mono-methacrylate (GM) as a dentine primer and to evaluate the possibility of allergic reaction. The efficacy of experimental dentine primers was evaluated by measuring the polymerization contraction gap width and the tensile bond strength. Allergic reaction was evaluated by the guinea-pig maximization test. The skin reaction was evaluated according to the criteria of the International Contact Dermatitis Research Group. Contraction gap formation was completely prevented and the tensile bond strength was not significantly affected by priming with GM on high-purity GM. The allergic response decreased when high-purity GM was employed as the challenger. It was concluded that the clinical use of the high-purity GM is beneficial as the delayed allergic reaction could be avoided with no detrimental effect on the dentine bonding.