Comparison of Bond in Roll-bonded and Adhesively Bonded Aluminums

Lap-shear and peel test measurements of bond strength have been carried out as part of an investigation of roll bonding of 2024 and 7075 aluminum alloys. Shear strengths of the bonded material in the F temper are in the range of 14 to 16 ksi. Corresponding peel strengths are 120 to 130 lb/inch. These values, which are three to five times those reported in the literature for adhesively bonded 2024 and 7075, are a result of the true metallurgical bond achieved. The effects of heat-treating the bonded material are described and the improvements in bond strength discussed relative to the shear strength of the parent material. The significance of the findings for aerospace applications is discussed

Influence of ceramic (feldspathic) surface treatments on the micro-shear bond strength of composite resin

Objective: To test the null hypothesis that surface treatment has no influence on the micro-shear bond strength between orthodontic composite resin cement and ceramics (feldspathic porcelain). Materials and Methods: Circular specimens of feldspathic porcelain were fabricated and randomly divided into six groups: (1) no treatment; (2) treatment with a mixture of acidic primer and silane agent for 20 seconds; (3) etching with 9.5% hydrofluoric acid; (4) etching with 9.5% hydrofluoric acid and coating with a mixture of acidic primer and silane agent for 20 seconds; (5) airborne-particle abrasion with 50-μm aluminum oxide; and (6) airborne-particle abrasion and coating with a mixture of acidic primer and silane agent for 20 seconds. The porcelain disks were then bonded to resin cylinders with composite resin cement. A micro-shear bond test was carried out to measure the bond strength. Moreover, each ceramic surface was observed morphologically by scanning electron microscopy. One-way analysis of covariance was used to compare the groups for differences in micro-shear bond strength. Results: The mean micro-shear bond strength varied as a function of surface treatment. It ranged from 3.7 to 20.8 MPa. The highest values for micro-shear bond strength were found when the surface was acid-etched with hydrofluoric acid and coated with silane. On the other hand, the control group (no treatment) had significantly lower micro-shear bond strength than all the other groups. Conclusion: The null hypothesis that the surface treatment has no influence on the micro-shear bond strength of orthodontic composite resin was rejected. The bond strength between ceramics and orthodontic resin cement is affected by the ceramic surface treatment. The bond failure was of the adhesive type, except with the hydrofluoric acid + silane group, where it was a cohesive bond failure

Sensitivity Analysis of Stress State and Bond Strength of Fiber-reinforced Polymer/Concrete Interface to Boundary Conditions in Single Shear Pull-out Test

The bond between fiber-reinforced polymer and concrete substrate plays a key role in the performance of concrete structures after strengthened by externally bonded fiber-reinforced polymer composite materials. The single shear pull-out test is generally used to determine the interface characteristics, and various bond–slip models have been proposed based on the results of this test. However, the sensitivity of the bond strength to the boundary conditions has not yet been considered in the available models in the literatures. This article presents an experimental and numerical study targeted at understanding the influence of the boundary conditions on the bond strength of the fiber-reinforced polymer/concrete interface in the single shear pull-out test. The validated finite element analysis by experimental results is used for the sensitivity study of the bond strength and stress state of the interface to the boundary conditions of the concrete block. It is found that the constraint height of the concrete block at the loaded side is an influential parameter on the stress state of the interface and the bond strength

Shear Bond Strength Comparison between Two Orthodontic Adhesives and Self-Ligating and Conventional Brackets

Objective: To evaluate and compare the shear bond strengths of two adhesives using two types of brackets: a conventional and a self-ligating bracket system. Materials and Methods: Sixty extracted human premolars were collected. The premolars were randomly divided into three groups of 20 teeth. All three groups were direct bonded. Groups 1 and 2 used light-cured adhesive and primer (Transbond XT) with a conventional (Orthos) and a self-ligating bracket (Damon 2), respectively. Group 3 used a light-cured primer (Orthosolo) and a light-cured adhesive (Blūgloo) with a self-ligating bracket (Damon 2). The specimens were stored in distilled water at 37°C for 40 ± 2 hours, after which they were debonded and inspected for Adhesive Remnant Index (ARI) scoring. Results: The mean shear bond strength was 15.2 MPa for group 1, 23.2 MPa for group 2, and 24.8 MPa for group 3. A one-way analysis of variance and post hoc Tukey test showed significant differences in bond strength (P \u3c .001) between group 1 and groups 2 and 3 but no significant difference (P \u3e .05) between groups 2 and 3. A Weibull analysis demonstrated that all three groups provided sufficient bond strength with over 90% survival rate at normal masticatory and orthodontic force levels. A Kruskal-Wallis test showed no significant difference (P \u3e .05) in ARI scores among all three groups. Conclusions: All three groups demonstrated clinically acceptable bond strength. The Damon 2 self-ligating bracket exhibited satisfactory in vitro bond strength with both adhesive systems used

Comparison of the effect of different surface treatments on the bond strength of different cements with nickel chromium metal alloy : an in vitro study

For success of any indirect metal restoration, a strong bond between cement and the intaglio surface of metal is imperative. The aim of this study is to evaluate and compare the effect of different surface treatment on the tensile and shear bond strength of different cements with nickel?chromium alloy. 120 premolars were sectioned horizontally parallel to the occlusal surface to expose the dentin. Wax patterns were fabricated for individual tooth followed by casting them in nickel chromium alloy. 60 samples were tested for tensile bond strength, and the remaining 60 for shear bond strength. The samples were divided into three groups (of 20 samples each) as per the following surface treatment: oxidation only, oxidation and sandblasting, or oxidation, sandblasting followed by application of alloy primer. Each group was subdivided into 2 subgroups of 10 samples each, according to the bonding cement i.e RM-GIC and resin cement. Samples were subjected to thermocycling procedure followed by evaluation of bond strength. Two-way analyses of variance (ANOVA) was performed to compare the means of tensile and shear bond strength across type of surface treatment and cement, followed by post hoc parametric analysis. For all tests ?p? value of less than 0.05 was considered statistically significant. The surface treatment of oxidation and sandblasting followed by application of alloy primer offered the maximum tensile and shear bond strength for both RM GIC and resin cement. Resin cement exhibited greater tensile and shear bond strength than RM-GIC for all the three surface treatment methods

Effect of surface treatment with sandblasting and Er,Cr:YSGG laser on bonding of stainless steel orthodontic brackets to silver amalgam

Objectives: Satisfactory bonding of orthodontic attachments to amalgam is a challenge for orthodontists. The aim of this in vitro study was to compare the shear bond strength of stainless steel orthodontic brackets to silver amalgam treated with sandblasting and Er,Cr:YSGG laser. Study Design: Fifty-four amalgam discs were prepared, polished and divided into three groups: In group 1 (the control group) the premolar brackets were bonded using Panavia F resin cement without any surface treatment; in groups 2 and 3, the specimens were subjected to sandblasting and Er,Cr:YSGG laser respectively, before bracket bonding. After immersing in distilled water at 37°C for 24 hours, all the specimens were tested for shear bond strength. Bond failure sites were evaluated under a stereomicroscope. Data was analyzed using one-way ANOVA and a post hoc Tukey test. Results: The highest and lowest shear bond strength values were recorded in the laser and control groups, respectively. There were significant differences in mean shear bond strength values between the laser and the other two groups (p<0.05). However, there were no significant differences between the sandblast and control groups (p=0.5). Conclusions: Amalgam surface treatment with Er,Cr:YSGG laser increased shear bond strength of stainless steel orthodontic brackets. © Medicina Oral

Development of Automatic Torque Bond Test

Proper bonding between adjacent pavement layers is very important to ensure good pavement performance. Manual torque bond test is known to be one of the tests to determine mechanical properties of bond between adjacent pavement layers. However, the test has several drawbacks that may affect the accuracy of results. This paper is focused on the development a mechanically controlled automatic torque bond test in order to eradicate the drawbacks associated with the manual torque bond test. A trial test and calibration of the newlydeveloped apparatus was performed to ensure the accuracy of results. The nominal loading rate of the manual torque bond test performed at 600Nm/min was found to be lower than the target loading rate, leading to a lower measured shear strength compared to that of the automatic torque test. It was also found that the appearance of lateral shear would not significantly affect the shear strength

A Comparison of Bond Strength Between Direct- and Indirect-bonding Methods

The purpose of this study was to evaluate and compare the shear bond strength and the sites of bond failure for brackets bonded to teeth, using two indirect-bonding material protocols and a direct-bonding technique. Sixty extracted human premolars were collected and randomly divided into three groups. The direct-bonded group (group 1) used a light-cured adhesive and primer (Transbond XT). One indirect-bonded group (group 2) consisted of a chemical-cured primer (Sondhi Rapid Set) and light-cured adhesive (Transbond XT), whereas the other group (group 3) used a light-cured primer (Orthosolo) and adhesive (Enlight LV). Forty hours after bonding, the samples were debonded. Mean shear bond strengths were 16.27, 13.83, and 14.76 MPa for groups 1, 2, and 3, respectively. A one-way analysis of variance showed no significant difference in mean bond strength between groups (P = .21). Furthermore, a Weibull analysis showed all three groups tested provided over a 90% survival rate at normal masticatory and orthodontic force levels. For each tooth, an Adhesive Remnant Index (ARI) score was determined. Group 2 was found to have a significantly lower ARI score (P \u3c .05) compared with groups 1 and 3. In addition, Pearson correlation coefficients indicated no strong correlation between bond strength and ARI score within or across all groups

Shear bond strengths of composite resin and giomer to mineral trioxide aggregate at different time intervals

The efficacy of the bond between the restorative materials and the pulp capping materials has an important role in the success of vital pulp therapy. Therefore, the aim of this study was to evaluate the shear bond strength of composite resin and giomer to MTA at different time intervals after mixing of MTA. Ninety cylindrical MTA samples were prepared and assigned to two groups (n=45) based on the restorative materials used (composite resin or giomer). Each group was subdivided into 3 subgroups (n=15) based on the evaluation intervals (immediately, 2.45 hours and 3 days after mixing MTA). After the bonding procedures, the shear bond strengths of the samples were measured in MPa at a strain rate of 0.5 mm/min. Data were analyzed with repeated-measures ANOVA, post hoc tests and t-test (P<0.05). Bond strength of composite resin was minimum at baseline but it increased significantly 2.45 hours after mixing MTA (P=0.002), with no significant changes in bond strength up to three days (P=0.08). Bond strength of giomer did not exhibit any significant changes from baseline to 2.45 hours after mixing MTA (P=078); however, at 3 days it reached a minimum (P=0.000). In addition, the means of bond strength of composite resin 2.45 hours and 3 days after mixing were significantly higher than those of giomer (P=0.001 and P=0.000, respectively). Bond strengths of composite resin 2.45 hours and also 3 days after mixing were significantly higher than those of giomer. In addition, the shear bond strength of giomer decreased over time; however, the shear bond strength of composite resin increased