Effect of different surface treatments on bond strength of recycled brackets to feldspathic porcelain

Aim: The aim of the study was to compare the shear bond strength of three different types of recycled brackets on porcelain facets following different surface treatments. Materials and Methods: Eighty-four porcelain facets were produced by duplication of the labial surface of a maxillary right first premolar. Each porcelain facet was individually embedded in autopolymerizing acrylic resin. A thin coat of sealant was also painted on the bracket base and cured for 15 s before applying the paste. The bracket was then positioned on the porcelain facet, pressed lightly and light-cured. Each specimen was loaded into a universal testing machine using Nexjen software for testing, with the long axis of the specimen perpendicular to the direction of the applied force. Then, the brackets were rebonded following different surface treatments (Laser, hydrofluoric acid, sandblasting with Al₂O₃, and silane treatment). Kruskal–Wallis analysis of variance and post hoc Wilcoxon signed-rank tests were performed to test the differences in shear bond strength values (p < 0.05). The significance of differences in the ARI scores was analyzed with chi-square test (p < 0.05). Results: Statistical analysis indicated significant differences among surface treatment procedures (p < 0.0001). In addition, the effect of the first and second bonding factors on shear bond strength behaviors was shown to be significant for the brackets (p < 0.001). Conclusion: The use of sandblasting, HF treatment and silanization procedure could be used for improving the rebond shear bond strength of zirconia brackets to porcelain surface. However, rebonding the brackets to porcelain surfaces may not be recommended due to the dramatic decrease in bonding values.     

脉冲激光改性聚氨酯表面无钯化学镀铜的实验研究

提出了一种在改性聚氨酯(PUR)材料表面进行金属化的方法。以掺杂了铜基金属复合物粉末的PUR浆料为基体,采用SPI光纤激光器(波长1 064 nm)对PUR表面进行刻蚀改性,达到传统化学镀铜中粗化和活化的目的,最后进行化学镀铜。对铜镀层进行了结合力、导电性以及延展性测试。结果表明,制备的铜镀层光亮、致密、结合力强、导电性好、延展性优良。通过扫描电子显微镜、X射线能谱仪、X射线光电子能谱(XPS)分析和俄歇电子能谱(XAES)分析对经过激光刻蚀改性的基体表面形貌和成分进行表征。探讨了激光刻蚀改性材料表面后,基体表面上铜元素的价态,分析XPS图谱和XAES图谱发现,激光刻蚀改性后的基体表面上铜元素以Cu+形式存在。研究了不同激光功率对刻蚀表面粗糙度的影响规律,通过胶带拉力实验验证了基体表面形貌与镀层结合强度的关系,实验结果表明,当用功率为7 W的激光刻蚀基体表面时,材料表面粗糙度值最大,并且其镀层结合力也最强。     

On the effect of pulsed laser ablation on shear strength and mode I fracture toughness of Al/epoxy adhesive joints

The present work describes an experimental study about the shear strength and the mode I fracture toughness of adhesive joints with substrates pre-treated by pulsed laser ablation. An ytterbium-doped pulsed fiber laser was employed to perform laser irradiation on AA6082-T4 alloy. Morphological and chemical modifications were evaluated by means of surface profilometry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Thick adherend shear tests were carried out in order to assess the shear strength while the mode I fracture toughness was determined using the double cantilever beam. For comparison, control samples were prepared using classical surface degreasing. The results indicated that laser ablation has a favorable effect on the mechanical behavior of epoxy bonded joints; however, while a + 20% increase was recorded for shear strength, a remarkable threefold enhancement of fracture toughness was observed with respect to control samples. XPS analyses of treated substrates and SEM observations of the fracture surfaces indicated that laser pre-treatment promoted chemical and morphological modifications able to sustain energy dissipation through mechanical interlocking. As a result cohesive failure within the adhesive bond-line was enabled under predominant peel loading.     

Effect of different surface shapes formed by femtosecond laser on zirconia-resin cement shear bond strength

Objective: The purpose of this study was to evaluate the effect of different surface shapes formed by femtosecond (FS) laser on zirconia (Y-TZP)-resin cement shear bond strength (SBS). Background data: All ceramic restoration is used as an alternative to metal-ceramic restorations, due to its better aesthetics, strength, and toughness properties. However, bond strength of restoration to tooth and other materials is effective to long term success of the restoration, and to achieve it surface treatment is required on ceramic surface. Materials and methods: Forty square-shaped zirconia samples were prepared and assigned to four groups of 10. The details of the groups are as follows: Group A, square-shaped recessed surface; Group B, square-shaped projection surface; Group C, circular-shaped recessed surface; Group D, circular-shaped projection surface. The SBSs values were performed with a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed statistically using analysis of variance (ANOVA) and Tukey HSD multiple comparisons tests. Results: The one-way ANOVA results on SBSs of the zirconia material bonded with resin cement revealed significant differences among the groups (p < 0.05). The Tukey HSD test results revealed that Group B and D had significantly higher SBS values than other groups (p < 0.05), but there were no significant differences between each other (p > 0.05). Additionally, Group A and C had significantly lower values than other groups (p < 0.05). Conclusions: Different surface shapes formed by FS laser provided a significant increase in SBSs. The SBS values of projection surfaces of circular and square-shapes are greater than that of recessed surfaces of circular and square-shapes.     

Bonding effectiveness of different dentin conditions on etch-and-rinse mode of two universal adhesives: the confocal laser scanning and shear bond strength

The purpose of this study was to evaluate the shear bond strength and the morphological differences of adhesive/dentin interface of two one-step universal adhesives to dentin using different dentin-conditioning methods with etch-and-rinse mode. Ninety-six dentin specimens were randomly divided into two groups based on application of two adhesives and assigned to three subgroups according to different dentin conditioning (wet-bonding; air-dried; rewetting). After etching and rinsing, experimental dentin conditioning was conducted on the etched dentin specimens. All specimens were subjected to shear bond strength testing using a universal testing machine, and all data were statistically analyzed using two- way analysis of variance with Tukey’s post hoc test. All debonded specimens were examined for fracture pattern by scanning electron microscopy (SEM). Adjunctively, one specimen per group was prepared by the same processing and longitudinally sectioned. Then, the infiltration ability of adhesives into dentin was examined by observing the interface using confocal laser-scanning microscopy (CLSM). Wet and Rewet groups exhibited significantly higher shear bond strength than dry groups on the etch-and-rinse system, regardless of different adhesives. The bond strength between wet and rewet groups showed no significant difference in Tukey’s test. Analysis of failure surface using SEM showed that predominant failure patterns were mixed in both the wet-bonding group and dry-bonding group. CLSM presented that resin penetration into etched dentin was enhanced similarly in wet and rewet group. Application of rewetting agents on dried dentin increased the bonding performance of universal adhesives on etch-and-rinse mode.     

304不锈钢箔的表面处理和粘接工艺研究

研究不同表面处理和胶粘剂实现5μm胶层对0.05 mm厚304不锈钢箔的粘接。试验表明:不锈钢表面粗糙度、偶联处理、胶粘剂和工艺对粘接效果有影响。最佳工艺:不锈钢箔先用丙酮清洗,于刻蚀剂中室温震荡5 min,水和乙醇清洗,再浸泡于浓度为0.5%KH-550乙醇水溶液30 s,乙醇清洗,晾干上胶,保温压粘,不锈钢箔剥离强度可达到9.4 N/cm,并耐丙酮等溶剂浸蚀。     

碱刻蚀玄武岩纤维对地质聚合物基木材胶黏剂胶接性能的影响

作为新型环保无机胶凝材料,地质聚合物在人造板产业中具有巨大的应用潜力,但地质聚合物的脆性不利于其与木材胶接.本文以改善地质聚合物基体的脆性,增强其与木材胶接强度为目的,采用不同浓度及温度的NaOH溶液对玄武岩纤维(BF)进行碱刻蚀,将碱刻蚀玄武岩纤维(HAF)与碱激发剂共混,制备碱刻蚀玄武岩纤维掺杂的地质聚合物(HAF...     

汽车前挡玻璃黏结支架脱落行为研究

针对3个制件(西南区域失效件:重庆件;华南失效件:广州惠州件和正常人为破坏件)分别使用傅里叶红外光谱仪、超景深显微镜和扫描电子显微镜3种仪器对它们进行观察并作对比分析,同时也分析了清洁溶剂异丙醇对支架的影响.结果表明,清洁溶剂异丙醇对支架的影响极小;,2个失效件的底涂部位和脱胶部位有不同程度的缺陷和裂纹,说明黏结部位的...     

Effect of hot-etching treatment on shear bond strength of zirconia to resin cement

ABSTRACT

The purpose of this study was to evaluate the effect of hot-etching surface treatment on the shear bond strength between zirconia ceramics and resin cement. Ceramic cylinders were divided randomly into 10 groups (n?=?10) according to different surface treatments (blank control; airborne particle abrasion; hot-etching for 10?min; hot-etching for 30?min; hot-etching for 60?min) and whether or not performed thermal cycling fatigue test. Flat enamel surfaces, were prepared from human permanent incisors and were bonded to the zirconia discs. All specimens were subjected to shear bond strength test by a universal testing machine. All data were statistically analysed using one-way analysis of variance and multiple comparison least significant difference tests (α?=?0.05). Hot-etching for 60?min treatment produced higher bond strengths than the other treatment. Surface treatment of zirconia with a hot-etching solution might enhance surface roughness and bond strength between zirconia and resin cement.     

Performance of protein-based wood bioadhesives and development of small-scale test method for characterizing properties of adhesive-bonded wood specimens

A small-scale test method to measure the tensile strength of adhesive-bonded wood strip specimens was developed by simple modification of commercially available binder clips. As bioadhesives, soy protein concentrate (SPC) and gelatin resins were prepared and were evaluated for shear and tensile bond strengths of bamboo and maple wood-bonded specimens. Titebond-II (TB-II), a commercially available wood glue was also tested to compare its bonding property to SPC and gelatin-based bioadhesives. TB-II glue showed the highest shear and tensile bond strengths with both bamboo and maple wood strips. Hot-pressing increased the shear and tensile bond strengths of SPC resin with wood specimens by 500% while the increase for gelatin resins was up to 200%. Roughness profile and surface properties were also characterized with an optical interferometric profiler and a scanning electron microscope. The results indicated that rougher surface significantly increased the bond strengths in both shear and tensile modes.     

Effect of the Etching Duration and Ultrasonic Cleaning on Microtensile Bond Strength Between Feldspathic Ceramic and Resin Cement

This study assessed the effect of different etching durations of feldspathic ceramic with hydrofluoric acid (HF) and ultrasonic cleaning of the etched ceramic surface on the microtensile bond strength stability of resin to a feldspathic ceramic. The research hypotheses investigated were: (1) different etching times would not affect the adhesion resistance and (2) ultrasonic cleaning would improve the adhesion. Ceramic blocks (6 × 6 × 5 mm) (N = 48) were obtained. The cementations surfaces were duplicated in resin composite. The six study groups (n = 8) were: G1—Etching with 10% aqueous HF (30 s) + silane; G2—10% HF (1 min) + silane; G3—10% HF (2 min) + silane; G4—10% HF (30 s) + ultrasonic cleaning (4 min) in distilled water +silane; G5—10% HF (1 min) + ultrasonic cleaning + silane; G6—10% HF (2 min) ultrasonic cleaning + silane. The cemented blocks were sectioned into microbars for the microtensile test. The etching duration did not create significant difference among the groups (p = .156) but significant influence of ultrasonic cleaning was observed (p = .001) (Two-way ANOVA and Tukey's test, p > 0.05). All the groups after ultrasonic cleaning presented higher bond strength (19.38–20.08 MPa) when compared with the groups without ultrasonic cleaning (16.21–17.75 MPa). The bond strength between feldspathic ceramic and resin cement was not affected by different etching durations using HF. Ultrasonic cleaning increased the bond strength between ceramic surface and resin cement, regardless of the etching duration.