Adhesion Durability Research Articles

The Effect of PAMAM Dendrimer on the Dentin Remineralization and Matrix Metalloproteinases Activity

The purpose of this study was to investigate the effect of G4.5 carboxyl-terminated poly dendrimer (PAMAM-COOH) on the dentin remineralization and the matrix metalloproteinases (MMPs) activity. The dentine samples were averagely divided into four groups: 100 mg/mL PAMAM-COOH group (A group), 10 mg/mL PAMAM-COOH group (B group), 2% (wt) chlorhexidine (CHX) group (C group) and deionized water group (Control group). MMP Activity Assay Kit was used to detect the activity of dentin endogenous MMPs in the four groups. The loss of dry mass of dentin after 30 d were measured. In situ zymography analysis was performed to detect the effects of PAMAM dendrimer in each group (except A group) on gelatinase activity in dentin. After incubation in artificial saliva for 7 and 14 d incubated, the remineralization of each group (except A group) in dentin surfaces were examined using a field emission-scanning electron microscope (FESEM). Compared with the control group, the dentin endogenous MMPs activity in A, B and C groups were all decreased ( P<0.05). The activity of endogenous MMPs in C group was lower than that of A and B groups ( P<0.001), but the difference between A and B groups was not statistically significant. The loss of dry mass in A, B and C groups were lower than that in control group ( P<0.05), but there were no significant difference in A, B and C groups. The in situzymography analysis showed that 48 h later, the dentin gelatinase activity in B group was inhibited compared with the control group, but the inhibitory effect was weaker than that of CHX. After 7 d and 14 d, there were no obvious mineralization in the control group, while distinct mineralization were observed in B group. The mineralization effect in group B was better than group C. G4.5 PAMAM-COOH could introduce remineralizationin and demineralizeddentin by effectively inhibiting endogenous MMPs and gelatinase, thus contributes as novel material to enhancing durability of adhesion.

Pilot-study switchable film dressing &amp; elderly skin/patients with chronic wounds: A non-interventional, non-placebo-controlled, national pilot study

Abstract Aim Film dressings were one of the first modern wound-dressing products. During the removal of the dressing skin stress occurs. An essential role is shearing force between skin and wound dressing playing [3]. This problem includes missing elasticity, flexibility and too strong adhesion [3,4]. The present study was initiated to evaluate if the switchable formulation of the adhesive ensures a durable and strong enough adhesion. Illumination of the film dressing with the UV-A lamp irreversibly switches the adhesion from strong to weak and guarantees a painless/comfortable removal of the dressing. Methods The present study evaluated suitability for use as well as user and patient satisfaction during use of the tested film on patients with chronic wounds. The used film dressing consists of a thin film backing with a non‑latex adhesive. Before removal the adhesion is reduced by illuminating the dressing with the UV-A lamp. Results 54 patients were included in the study. At each dressing change, pain level after dressing change was rated lower compared to the pain level before dressing change. Overall, pain level decreased over the study period. Reactions on the wound edge/wound surroundings have not been reported. Discussion The clinicians gave favourable scores for the tested film dressing. The overall satisfaction with the product was rated very good. Tolerability such as pain during wearing the dressing and upon removal were given good scores. Skin irritation caused in the use of the film dressing did not occur. Conclusion The switchable function of the adhesive allows the adhesion of the film dressing to the skin to be reduced when illuminated by the supplied UV-A lamp. The results of the present study show that the reduced adhesion upon illumination enables easy and comfortable removal of the dressing.

Evaluation of adhesion durability of Ni–P coating using repeated Laser Shock Adhesion Test

This study aims to evaluate the adhesion strength and durability of NiP coatings in a non-contact manner using the Laser Shock Adhesion Test (LaSAT). A hard coating of electroless NiP deposited on carbon steel substrate (SKD11) was prepared, and the effect of post heat treatment on adhesion was comprehensively investigated in this study. With the LaSAT, strong elastic waves induced by pulsed YAG laser irradiation applies tensile stress to the coating/substrate interface resulted in interfacial delamination. Computation of the elastic-wave propagation using finite element method (FEM) was carried out to estimate the interfacial tensile stress. In addition, the adhesion durability was investigated by repetitive pulsed-laser irradiation, and the relationship between adhesion strength and the number of laser irradiation cycles until delamination was obtained. Finally, the effects of heat treatment on the adhesion strength and durability of the NiP coating were discussed. Owing to the post-heat treatment, it is found that the hardness of coating, adhesion strength and durability were improved. Indentation test reveals that the coating hardness increases from 792 HV to 1163 HV. LaSAT quantitatively evaluated the adhesion strength with increasing from 84.4 MPa to 143.9 MPa. In addition, repetitive LaSAT reveals that adhesion durability improves twice or more. This result was verified using the tensile adhesion test and microscopic observations of the interface. Therefore, the present LaSAT is a quick measurement for the adhesion durability of hard coating, and it may shed some light on quality control of surface coatings.

Fabrication and coating adhesion study of superhydrophobic stainless steel surfaces: The effect of substrate surface roughness

In this study, superhydrophobic 17–4 PH stainless steel surfaces were fabricated for applications in harsh marine environment. The impacts of the substrate's surface roughness on the fabrication and durability of the developed superhydrophobic coating, comprised of a Zn electrodeposited layer capped with 0.05 M stearic acid, were investigated for the first time in this study. Various micron and sub-micron scale finished surfaces with different surface roughness, namely as-received (Ra ~ 4.62 μm), sandblasted (Ra ~ 11.93 μm), and ground (Ra ~ 0.39 μm) surfaces, were fabricated, followed by applying Zn electrodeposited coating to improve the water-repellent properties of the stainless steel substrate. The adhesion durability of the coating and corrosion behavior of the electrodeposited Zn layer were deliberated by studying the combined impacts of the initial surface roughness, and super-hydrophobicity of the surfaces. The cyclic potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results measured in aerated 3.5 wt.% NaCl electrolyte at room temperature along with salt spray testing highlighted a significantly better uniformity and adhesion durability of the coating on the as-received substrate correlated to its optimum surface roughness. The best coating adhesion was obtained on surfaces with an initial surface roughness of 4.62 ± 0.15 µm. The coated 17–4 pH stainless steel surfaces were also found to be effective in preventing the aggressive chloride ions from approaching the substrate, leading to the improved corrosion performance of the material.

Hidróxido de cálcio versus hibridização em capeamentos pulpares: revisão de literatura

O desafio da manutenção da vitalidade de uma polpa exposta acidentalmente ou por cárie tem sido tema de investigações por muitos anos. O uso do hidróxido de cálcio como material capeador na clínica odontológica é um costume e vários estudos comprovam seu excelente resultado. Entretanto, umnovo material capeador é sugerido, o adesivo dentinário, setomando um dos temas mais controvertidos na odontologia. Objetivou-se avaliar por meio de uma revisão de literatura, a comparação destas técnicas em relação à efetividade. Foram utilizadas as palavras-chave “capeamento pulpar”, “hidróxido de cálcio” e “hibridização” nas bases de dados PubMed e BVS. Foram escolhidas as referências que tratavam dos assuntos relacionados ao tema proposto, publicadas durante os últimos 20 anos. O adesivo dentinário produziria uma camada hibridaque proveria um selamento efetivo e permanente contra a invasão bacteriana, promovendo a cicatrização pulpar, sendo indicado para os procedimentos de capeamento pulpar. Assim como o hidróxido de cálcio foi contestado a respeito da sua incapacidade de promover um selamento permanente contra a invasão bacteriana, a integridade e a durabilidade da adesão alcançada com os adesivos de dentina, podem ser questionadas. Apesar de ostentar promessa e oferecer um tratamento diferente possível no futuro, a falta de documentação de sucessos clínicos ao longo prazo para a realização decapeamentos pulpares com os sistemas adesivos em experimentos clínicos controladosdeveser examinado contra a literatura que demonstra um sucesso com o uso do hidróxido de cálcio de 75-90% à mais de 12 anos.

Evaluation of an Epoxy-Based Nanosilicacomposite Lining in H2SO4 Solution for Anticorrosion of Sewerage Concrete Structures

This work presents the performance of a SiO2-epoxy nanocomposite lining for the anticorrosion of the concrete structures in sewer networks. Nanocomposite lining on the concrete substrate surface of the 15 phr (part per hundred epoxy resin) amine-cured epoxy polymer containing 3.0 phr of nano-SiO2 was prepared by intercalating epoxy into the SiO2 via direct mixing process. The silica exfoliation was monitored by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The barrier feature of epoxy the base nanocomposite against water and sulfuric acid solution was evaluated. The results showed that the nanocomposite lining was of a great barrier against these corrosive environments due to the intercalation and exfoliation caused by the dispersion of the SiO2 nanoparticles into the epoxy matrix. The rate of the H2SO4 into the nanocomposite lining was also investigated by measurement of the depth of the sulfur element penetrated layer using the coupled Scanning Electron Microscopy (SEM)/Energy dispersive X-ray spectrometer (EDS). Deterioration behavior of the adhesion strength of the nanocomposite lining was studied. The nanocomposite lining shows a significant improvement of bond strength in comparison to the neat epoxy lining. The durability of the nanocomposite lining adhesion when the lining systems exposed to water and the sulfuric acid solution is also improved significantly.

The Influence of the Ionic Form of Input Diatomite on the Cathodic Disbondment of Bitumen–Polymer Coatings

The effect of diatomite introduced as an active filler in nickel 2(+) and sodium (+) ionic forms on the adhesion resistance of bitumen–diatomite protective systems during their cathodic polarization is studied. A significant effect of the introduced diatomite clay, the method of its activation, its ionic form on the cathodic exfoliation, and, as a result, the adhesive durability of bitumen–polymer protective coatings during their cathodic polarization are shown. This effect can be used to create protective anticorrosion coatings with increased durability.

Correction to: The use of clays for chlorhexidine controlled release as a new perspective for longer durability of dentin adhesion

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Role of the functional monomer 10-methacryloyloxydecyl dihydrogen phosphate in dentin bond durability of universal adhesives in etch-&-rinse mode.

This study aimed to determine the role of the 10-methacryloyloxydecyl dihydrogen phosphate (MDP) in dentin bond durability of universal adhesive in etch-&-rinse mode through bond strength tests after different degradation conditions. This study used the MDP-containing universal adhesive, Clearfil Universal Bond Quick (CU), and an experimental adhesive (NM) made with the same ingredients as CU, excluding MDP. Shear bond strength (SBS) to dentin were obtained in etch-&-rinse mode with or without MDP. CU in self-etch mode was used as a comparison. The groups were divided into three types: 1) subjected to thermal cycling; 2) subjected to long-term water storage; and 3) stored in water for 24 h, as a baseline. The discrepancies in the mean SBS of the CU and NM groups become prominent with prolonged degradation periods. This study indicates that the MDP in universal adhesive might play a key role in enhancing dentin bond quality even when etch-&-rinse mode is used.

Progress in biomodification of dentin type Ⅰ collagen by different types of cross-linkers

Establishing a stable resin-dentin hybrid layer is an effective method to improve the adhesion durability of the restoration. The biomodification of dentin by cross-linkers can enhance the mechanical properties of collagen and resistance to enzymatic hydrolysis while, inhibiting the process of demineralization and promoting the remineralization of dentin, which has the potential clinical applicability of preventing dental caries and improving adhesive property. This review summarizes the biomodification of dentin type Ⅰ collagen by different cross-linkers.

Tough polyacrylamide-tannic acid-kaolin adhesive hydrogels for quick hemostatic application.

Adhesive hydrogels for wet and dynamic tissues are important for biomedical applications in order to withstand cyclic loading such as in the case of hemorrhaging control on the curved skins and heart tissues. However, the fabrication of hydrogels with strong mechanical properties, high adhesion strength, and hemostatic efficiency remains a big challenge. Inspired by the great adhesive behavior of mussels and Arion subfuscus, novel adhesive and hemostatic polyacrylamide-tannic acid-kaolin (PAAm-TA-KA) hydrogels were reported in this work. The hydrogels displayed high strength and toughness due to their physical and chemical crosslinking structures. The abundant catechol groups on tannic acid endow the hydrogels with strong and durable adhesion strength of up to 500kPa on porcine skin. When applied onto human skin, the hydrogels could be easily peeled off without leaving any remains and causing any damages. The kaolin nanoparticles incorporated in the PAAm-TA-KA hydrogels not only served as a physical crosslinking agent, but an activator of the blood clotting factor FXII for accelerating the formation of thrombus. The strong tissue adhesion and blood coagulant potential of the PAAm-TA-KA hydrogels imparted them high hemostatic efficiency. The free-standing, adhesive, tough, cytocompatible, and hemostatic hydrogels are highly promising for traumatic bleeding control materials.

Oxygen inhibition layer: A dilemma to be solved.

Objective: This study aimed to evaluate the thickness of oxygen inhibition layer (OIL), produced on various composite materials, and to compare their interlayer shear bond strength (SBS), by treating the OIL with various agents.Materials and Methods: The thickness of OIL of three different composite materials (120 specimens divided into three groups) Group 1 – Ivoclar Tetric N-Ceram (nanohybrid composite), Group 2 – Ivoclar Te Econom Plus (microhybrid composite), and Group 3 – GC EverX Posterior (a short glass fiber-reinforced composite) was evaluated. Each group was divided into four subgroups (A, B, C, and D) depending on the surface treatment given – no surface treatment (control group), ethanol, water spray, and grinding with SiC paper. This was followed by interlayer SBS testing.Statistical Analysis: The data were statistically analyzed using ANOVA at a significance level of P < 0.05. Tukey’s post hoc analysis was performed following ANOVA to determine differences among the groups.Results: The control group showed higher SBS irrespective of the type of composite material. The group treated with SiC paper resulted in the lowest interlayer SBS among all groups. Glass fiber composite showed higher interlayer SBS compared to both nanohybrid and microhybrid composites, irrespective of the surface treatment given.Conclusion: The OIL, which acts as an intermediate layer, is retained on the surface of the composite even after treatment with ethanol and water spray. The presence of an OIL improved the interlayer SBS of two adjacent composite layers and led to more durable adhesion. Rather, the absence of an OIL adversely affected the bond strength and led to adhesive interfacial failures.

Enamel and Dentin Bond Durability of Self-Adhesive Restorative Materials.

To use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the durability of adhesion of self-adhesive restorative materials compared to composite resin bonded with a universal adhesive. A universal adhesive, Prime & Bond Active, was used in self-etch mode to bond Z-100 composite resin to enamel and dentin. Three commercially available restorative materials and one experimental material with self-adhesive properties, Activa (A), Fuji II LC(F), and Equia Forte (E) and ASAR-MP4 (S) were also bonded to enamel and dentin. The SBS and SFS were determined for all materials. A staircase method was used to determine the SFS with 10 Hz frequency for 50,000 cycles or until failure occurred. On enamel, S generated similar values to the adhesive/composite materials and higher values than F, E, and A. On dentin, the composite/universal adhesive showed significantly higher SBS and SFS than the self-adhesive materials. S, F, and E generated higher values than A on dentin. SBS and SFS values to enamel were similar for all materials tested except Activa which generated lower enamel values. On dentin surfaces, the self-adhesive materials generated similar SBS and SFS, with the exception of Activa. Those values were lower than that generated with composite resin and a universal adhesive.

Enhancement performance of application mussel-biomimetic adhesive primer for dentin adhesives.

In this study, we evaluated bioinspired adhesive primers for durable adhesion between dentin and composite resins. N-3,4-Dihydroxyphenethyl methacrylamide (DMA) primer monomer (small bifunctional group molecules containing catechol and acrylic groups at opposite ends) was prepared to mimic the interaction between the catechol group and the mineral interface of marine mussels. The shear bonding strength, microleakage, degree of conversion, contact angle, and compatibility were tested. The shear bond strength was significantly improved, and microleakage was diminished after the application of the DMA primer. However, the degree of conversion was decreased. The wettability of the dentin was enhanced, and the DMA primer showed no negative influence on cell proliferation. The results of this study showed the possibility of using DMA primers in clinical practice. This may provide a new strategy for improving adhesion durability.

Improve Surfaces properties of ABS Products fabricated by fused deposition modeling (FDM) 3D Printing

FDM (fused deposition modeling) 3D printing products often suffer from high surface roughness and low durability compared to conventional methods. In this paper, the effect of surface treatment after printing and coating with a layer of metal on its properties has been studied, The mechanical surface treatment methods (sandpaper) and chemical (solvent treatment) were compared and their effect on the adhesion strength of the deposited metal layer on the surface. The surface of the ABS product was coated with a layer of metal, the effect of both treatment and coating on the mechanical properties of printing products was studied. The results showed a clear decrease in surface roughness after surface treatment, where surface roughness decreased by 92%, and the best result was when grinding with sandpaper (2000 Grit) was Ra 0.35 μm. The tensile strength after acetone surface treatment was improved by 50% and after coating the product with a layer of metal by 56.25%. The adhesion test of the surface-deposited metal (CROSS-CUT) was conducted, and the result showed that the best adhesion durability was when the surface was treated with acetone vapor before coating.

Muscle-Inspired Self-Healing Hydrogels for Strain and Temperature Sensor.

Recently, self-healing hydrogel bioelectronic devices have raised enormous interest for their tissue-like mechanical compliance, desirable biocompatibility, and tunable adhesiveness on bioartificial organs. However, the practical applications of these hydrogel-based sensors are generally limited by their poor fulfillment of stretchability and sensitivity, brittleness under subzero temperature, and single sensory function. Inspired by the fiber-reinforced microstructures and mechano-transduction systems of human muscles, a self-healing (90.8%), long-lasting thermal tolerant and dual-sensory hydrogel-based sensor is proposed, with high gauge factor (18.28) within broad strain range (268.9%), low limit of detection (5% strain), satisfactory thermosensation (-0.016 °C-1), and highly discernible temperature resolution (2.7 °C). Especially by introducing a glycerol/water binary solvent system, desirable subzero-temperature self-healing performance, high water-retaining, and durable adhesion feature can be achieved, resulting from the ice crystallization inhibition and highly dynamic bonding. On account of the advantageous mechanoreception and thermosensitive capacities, a flexible touch keyboard for signature identification and a "fever indicator" for human forehead's temperature detection can be realized by this hydrogel bioelectronic device.

Nano Clay Additive Effect on Shear Strength of GFRP Joints

Adhesively bonding joints are widely used in various industries such as aviation, automotive and marine due to its advantages such as lightness, sealing ability, low cost, corrosion resistance and uniform stress distribution. Increasing the quality and durability of adhesives using various methods is a matter of interest both in science and engineering. This study investigates the role of the addition of Nano-clay particles to epoxy resin on the shear strength of single lap GFRP bonding joints. For this aim, Nano-silica particles were added in epoxy resin, 1%, 2%, 3% and 5% by weight. The experimental results obtained from lap shear test showed that the increase in shear strength was about 36, 91 and 63% for 1, 2 and 3 wt. respectively.

Mathematical model of adhesion junction of layers during coextrusion

Nine theories of polymer adhesion during coextrusion are researched. Two approaches to describing adhesion are presented – thermodynamic and molecular-kinetic ones. The factors, determining the durability of adhesion junction, are analyzed. The stages of adhesion connection formation are presented. The adhesion junction emergence model as a result of intermolecular interaction is described. As a result of calculations the following dependencies are got: the dependence of ply separation energy on the contact length of polyisobutylene adhesion junction of different molecular weight, the dependence of ply separation energy on molecular weight of polyisobutylene adhesion junctions got during different time, the dependence of adhesion durability on squared difference of polymer solubility parameters, the dependence of interdiffused zone width in the time.

The use of clays for chlorhexidine controlled release as a new perspective for longer durability of dentin adhesion.

The adhesive systems have the function to establish the connection between the restorative material and dental tissue, therefore it is of fundamental importance, because failures in the adhesive interface can reduce the life of a dental restoration. This study investigated the possibility of using the adhesive layer as a chlorhexidine modified release system evaluating their impact on the properties of these systems as well as evaluating the impact of these systems on immediate and post-aging dentin adhesion. Were used a matrix with BisGMA, UDMA, HEMA and TEGDMA copolymer and clay particles (Dellite 67G); associated with a chlorhexidine and a camphorquinone photoinitiator system. The properties of these systems were evaluated by the XRD, FTIR spectrophotometer, flexural strength, elasticity modulus, drug release, enzymatic inhibition and dentin adhesion resistance. The presence of the clay can raise the mechanical properties of the adhesive systems engendering a more resistant hybrid layer and led to a more sustained release of chlorhexidine in the systems, allowing a longer effective period of MMP-2 inhibition. The hypothesis that the addition of clays as release modulators could increase the effectiveness of these drugs in inhibiting the dentin's MPPs and consequently enhancing the adhesive durability was confirmed. These results indicate that the controlled release of chlorhexidine is able to reduce the process of loss of adhesion presenting itself as a promising system to increase the longevity of dental restorations.

The Effects of Aluminablasting on Bond Durability Between Universal Adhesives and Tooth Substrate.

The aim of this study was to determine the effect of aluminablasting on the bond durability of universal adhesives and adherent surface characteristics. Adhese Universal (Ivoclar Vivadent), All-Bond Universal (Bisco), Bondmer Lightless (Tokuyama Dental), G-Premio Bond (GC), and Scotchbond Universal (3M ESPE) were used in self-etch mode. The prepared bovine enamel and dentin specimens were divided into two groups based on whether they received an aluminablasting prior to application of the universal adhesives. The resin composite bonded specimens were stored in distilled water at 37°C for 24 hours, following which the shear bond strength (SBS) of half of the specimens was measured (24-hour group). The other half was subjected to 30,000 thermal cycles between 5 and 55°C before SBS measurement (TC group). Surface roughness (Ra) and surface free energy (SFE) of the adherent surfaces were also measured, and scanning electron microscopy observation and scanning electron microscopy/energy-dispersive X-ray analysis were carried out. Most of the adhesives did not show any significant differences in enamel SBS values between the two pretreatment groups, regardless of the storage condition. However, the dentin SBS values were significantly lower in specimens that underwent aluminablasting compared with those that did not, irrespective of their storage conditions. Significantly higher Ra and SFE values were observed in the enamel and dentin of specimens that underwent aluminablasting. Although aluminablasting increased the Ra and SFE values of enamel and dentin, its effect on the SBS value was dependent on the tooth substrate. In addition to C, O, Na, Mg, P, and Ca, the element Al was detected in the enamel and dentin of samples that had undergone aluminablasting. These results suggest that although aluminablasting of the tooth surface is thought to be effective for modification of the adherent surface, it may not enhance enamel bond performance and may also adversely affect the dentin bond effectiveness of the universal adhesives.