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Objectives: To compare marginal gap width and depth with different cementation systems, excess removal, and after polishing. Method and materials: In total, 80 composite crowns were milled, divided into ten groups, and cemented on identical artificial teeth. Eight crowns per group were fixed with (i) zinc phosphate cement (ZnOPh), (ii) glass-ionomer cement (GIC), (iii) resin-reinforced glass-ionomer cement (GIC mod), (iv) dual-curing adhesive composite (Comp dual), or (v) dual-curing self-adhesive composite (Comp SE dual). Excess removal was performed with a scaler after brief light-cure (tack-cure), final light-cure, during rubber or gel phase or by wiping with foam pellet. Curing was completed in chemical, dark cure, or light-curing modus. The specimens were polished and stored in water (37°C). The margins were digitized using a 3D laser-scanning microscope (VK-X100 series, Keyence). The width and the depth of the marginal gap were measured at 10 points between the crown margin and the preparation margin. Results: The width after excess removal varied between 65.1 ± 15.7 µm (Comp dual, wipe, with polishing) and 208.6 ± 266.7 µm (Comp SE dual, dark cure, without polishing). The depth varied between 29.8 ± 22.2 µm (Comp dual, wipe, with polishing) and 89.5 ± 45.2 µm (Comp SE dual, dark cure, without polishing). The impact on gap width and depth was detected for fixation material, excess removal, and polishing. Conclusion: The gap depth and width depend on the luting material and the mode of access removal. Polishing can improve the gap quality, especially for GIC and resin-based systems. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of adhesive type and long-term aging on the shear bond strength (SBS) between silicabased ceramics and composite cement (CC). Materials and Methods: Lithium-silicate (LS), feldspathic (FD) and polymer-infiltrated ceramic (PIC) blocks were sectioned (10 x 12 x 2 mm) and divided into 24 groups considering the factors: "ceramics" (LS, FD, and PIC), "adhesive" (Ctrl: without adhesive; 2SC: 2-step conventional; 3SC: 3-step conventional; 1SU: 1-step universal), and "aging" (non-aged or aged [A]). After the surface treatments, CC cylinders (n = 15, ɸ=2mm; height = 2mm) were made and half of the samples were subjected to thermocycling (10,000) and stored in water at 37°C for 18months. The samples were submitted to SBS testing (100 kgf, 1mm/min) and failure analysis. Extra samples were prepared for microscopic analysis of the adhesive interface. SBS (MPa) data was analyzed by 3-way ANOVA and Tukey's test (5%). Weibull analysis was performed on the SBS data. Results: All factors and interactions were significant for SBS (p<0.05). Before aging, there was no significant difference between the tested groups and the respective control groups. After aging, the LS_1SU (22.18±7.74) and LS_2SC (17.32±5.86) groups exhibited significantly lower SBS than did the LS_Ctrl (30.30±6.11). Only the LS_1SU group showed a significant decrease in SBS after aging vs without aging. The LS_1SU (12.20) group showed the highest Weibull modulus, which was significantly higher than LS_2SC_A (2.82) and LS_1SU_A (3.15) groups. Conclusion: No type of adhesive applied after silane benefitted the long-term adhesion of silica-based ceramics to CC in comparison to the groups without adhesive. [ABSTRACT FROM AUTHOR]

Robust adhesion is crucial for ionic hydrogels in flexible electronic pressure and strain sensors. Herein, we design a transparent and strong adhesion electronic pressure and strain sensor based on a multifunctional ionic hydrogel with double network using polyacrylamide (PAM) and gum arabic (GA). First, the effect of ionic type on the mechanical properties of hydrogels was measured. The GA/PAM–Fe3+ hydrogel with high extensibility (1835%) and toughness 1. 47 MJ / m 3 was selected as the best sensor material. Moreover, the GA/PAM–Fe3+ hydrogel has good adhesion property with various substrates, and the maximum peel strength of the hydrogel to skin could reach up to 123.9 N/m. Furthermore, the resistance of GA/PAM–Fe3+ hydrogel is sensitive to a wide strain window and the gauge factor shows stable and reliable change during deformation. Due to its compliant and excellent adhesive properties, strain sensors based on this hydrogel can be well fixed on the epidermis without adhesive tape, and can perceive large and gentle body movements. These characteristics demonstrate that GA/PAM–Fe3+ hydrogel is promising for a broad range of practical applications in wearable sensors. [ABSTRACT FROM AUTHOR]

Cellulose-based hydrogels have attracted considerable attention in biomedical engineering. However, existing cellulose-based adhesive hydrogels have several limitations, including poor wet adhesion, average antimicrobial activity and a lack of benign on-demand detachment. Using a dual-crosslinked design strategy, we created a cellulose-based hydrogel (ACCPFM) by combining polymerisable allyl cellulose, carboxymethyl chitosan and the aldehyde-cation copolymer P(FPMA-co-META). Covalent (Schiff base) and non-covalent (electrostatic interaction and hydrogen bonding) crosslinking enhance the mechanical performance of the prepared hydrogel. The introduction of P(FPMA-co-META) into the cellulose network architecture endowed the ACCPFM hydrogel with an impressive antibacterial capacity (bacterial reduction: > 95%). The ACCPFM hydrogel used the hygroscopicity of the hydroxy, carboxyl and cationic moieties to remove interfacial water on the tissue surface and then formed physical and dynamic covalent cross-links with the tissue (shear strength: > 50 kPa, tensile strength: > 70 kPa and interfacial toughness: > 110 J m−2). Notably, due to the dominance of physical and dynamic covalent crosslinking, which transforms timescale-dependent, on-demand detachment was achieved by applying a tailored benign solution (sodium bicarbonate/glycine) at different stages, providing a wider time window and fault-tolerance for the adhesion process. Given the ACCPFM hydrogel's strong wet adhesion, excellent antimicrobial capability and cytocompatibility, and benign on-demand detachment from tissues, cellulose-based hydrogels are expected to have potential applications in the biomedical field. [ABSTRACT FROM AUTHOR]

Self‐assembly is an effective approach to construct complicated structures. Polyrotaxanes (PRs) as one of the typical polymer types with complex structure, own interlocked structures and dynamic components, in which it results in unique characteristics and functions. Currently, the synthesis of which involves covalent reactions to hinder the development of polyrotaxanes. Herein, we employed supramolecular interactions as well as dynamic covalent bonds to synthesize PRs by sequential self‐assembly. First, we prepared M1 possessing two diamine structures and M2 of a bisammonium salt with two dibenzylammonium (DBA) units modified by two stoppers at its ends, then M1 and M2 self‐assembled into supramolecular polymers stemming from hydrogen bonding of [N+−H ⋅ ⋅ ⋅ O] under high concentrations. After adding 2,6‐pyridinedicarboxaldehyde (M3), the imine bond formation enabled the generation of macrocycles, transforming supramolecular polymers into PRs. Besides, the solution of polyrotaxanes was applied as the adhesive for diverse hard and soft materials. This strategy provides an important approach for synthesizing PRs, accelerating the advances of mechanically interlocked polymers. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of colloidal platinum nanoparticles (CPN) on the durability of resin-dentin bonding performance with contemporary adhesives. Sixty non-carious human maxillary premolars were subjected to microtensile bond strength (µTBS) testing and divided into two main groups: CPN-treated and untreated. Within each group, specimens were randomly allocated to Clearfil Megabond 2 (MB2), Scotchbond Universal Plus Adhesive with self-etch mode (SE-SUP), and etch-and-rinse mode (ER-SUP) subgroups (n = 10/group). CPN was applied to dentin in the MB2 and SE-SUP groups for 20 s, followed by rinsing before adhesive application. In the ER-SUP group, CPN was applied after etch-and-rinse. The µTBS was tested after 24 h, 6 months, and 1 year, and the fracture modes were observed using SEM. The µTBS data were analyzed using a two-way ANOVA and post-hoc Tukey HSD test (α = 0.05). An additional twelve premolars underwent TEM/STEM/EDX for ultra-morphological observations. The application of CPN significantly prevented a decline in the µTBS of both the MB2 and SE-SUP groups. No significant decrease was observed in the ER-SUP group, either with aging or CPN application. Ultra-morphological images revealed platinum nanoparticles attaching to the collagen fibrils of the hybrid layer regardless of aging. It was highlighted that the nanoparticles attached to the banded collagen in the aging groups were observed. CPN exhibits the potential in enhancing the longevity of resin-dentin bonding in SE mode. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) plays a critical role in elastomers, adhesives, and self-healing materials. We selected the most commonly used aromatic isocyanates, 4,4′-methylene diphenyl diisocyanate (MDI) and tolylene-2,4-diisocyanate (TDI), and the most commonly used aliphatic isocyanates, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane-4,4′-diisocyanate (HMDI), as raw materials, combined with polytetramethylene ether glycol (PTMG) and 1,4-butanediol (BDO) to successfully synthesize five PU materials. The effects of isocyanate structure on polymerization rate, hydrogen bonding, thermal properties, phase separation, wettability, self-healing performance, adhesion, and mechanical properties were systematically investigated. The results show that isocyanates with higher symmetry facilitate hydrogen bonding, but excessive flexibility and crystallinity may inhibit its formation. MDI-based PU exhibits the highest hydrogen bonding index (HBI) of 4.10, along with the most distinct phase separation and the highest tensile strength of 23.4 MPa. HMDI-based PU demonstrates the best adhesion properties, with the highest lap shear strength of 7.9 MPa, and also exhibits excellent scratch healing ability. IPDI-based PU shows good self-healing performance, recovering 88.7% of its original tensile strength and 90.6% of its original lap shear strength after heating at 80 °C for 24 h. Furthermore, all the samples can be reprocessed by melt or solution methods, showing excellent recyclability. [ABSTRACT FROM AUTHOR]

Tape is a type of trace evidence commonly seen in forensic science. Little to no research has been published regarding the optimal storage material for pressure‐sensitive adhesive (PSA) tape. The purpose of this project was to determine the substrate with the least amount of interference for storing PSA tape. Interferences such as difficulty removing tape from the substrate or substrate components leaching into the adhesive can affect the analysis. This was a long‐term study in which samples were stored on various substrates for nearly 10 years. Ten different tape samples were placed on eight different substrates for a total of 80 samples. The substrates included typical materials currently used for tape storage as well as other, less common materials. The tape samples were evaluated for ease of removal at various time intervals. The adhesives from each tape were analyzed at similar time intervals by Fourier transform infrared spectroscopy (FTIR). In addition, the adhesives were analyzed by pyrolysis gas chromatography–mass spectrometry (PyGC‐MS), scanning electron microscopy with energy‐dispersive spectroscopy (SEM‐EDS), and x‐ray fluorescence (XRF) at the last time interval (112 months) and compared to the adhesive tape samples from the original rolls of tape to determine if there was any adverse effect from the substrates during storage. The FedEx backing was the only substrate that had no adverse effects regarding ease of removal. The substrates that had the least effect on the adhesive for both short‐term and long‐term storage included FedEx backings, adhesive sheet backings, and polyester transparency sheets. [ABSTRACT FROM AUTHOR]

Background: Differences in the effects of cream‐type denture adhesives and home liners remain unclear. Objective: This cross‐sectional study aimed to clarify the differences in the oral‐hygiene status and masticatory performance between participants using cream‐type denture adhesives and those using home liners. Methods: Masticatory performance with and without cream‐type denture adhesives and home liners was evaluated using colour‐changeable chewing gum. Oral hygiene was assessed using the tongue coating index (TCI). Propensity‐score matching was performed using oral moisture, presence of palatal or mandibular protuberances, type of residual ridge, denture type (complete or partial denture), and denture retention as background factors. Wilcoxon signed‐rank test was used to examine the differences in masticatory performance with and without cream‐type denture adhesives and home liners and differences in masticatory performance and TCI between the cream‐type denture adhesive and home‐liner groups. Results: This study included 38 and 40 cream‐type adhesive and home‐liner users, respectively, and 17 pairs were obtained after propensity‐score matching. The Wilcoxon signed‐rank tests showed that masticatory performance was significantly different with and without the use of home liners, and higher values were obtained with the use of home‐liners. However, the cream‐type denture adhesive and home‐liner groups showed no significant differences in terms of the change in masticatory performance with the use of them. Furthermore, Wilcoxon signed‐rank tests showed that TCI values were significantly high in the cream‐type adhesive group. Conclusion: The findings in this study suggest that home liners improve masticatory performance and that participants regularly using cream‐type denture adhesives have poorer oral hygiene. [ABSTRACT FROM AUTHOR]

Using adhesively bonded joints is an effective strategy for achieving lightweight designs. However, understanding the long‐term performance of these bonded joints remains a critical concern. Creep is a time‐dependent phenomenon induced by sustained mechanical loads, which can lead to viscous strain in adhesive materials. This strain has the potential to cause cracking in bonded structures over time. This study aims to investigate the creep and post‐creep behaviors of adhesively bonded aluminum joints, focusing on two crucial parameters: creep load level and creep duration. Butt adhesive joint (BAJ) specimens were fabricated and exposed to varying creep loads and times. Subsequently, quasi‐static tensile tests were conducted to assess the residual mechanical properties. The results indicated that higher creep loads resulted in increased creep deformations at constant creep durations. Furthermore, a downward trend was observed in the residual tensile mechanical properties of BAJ specimens following creep. Specifically, higher creep load levels and longer times led to more pronounced reductions in joint strength, strain, and stiffness. These reductions in joint mechanical properties were corroborated through joint fracture surface analysis. Additionally, mathematical models were developed using response surface methodology (RSM) to predict the experimental joint residual mechanical properties under different creep loads and times. Highlights: Investigation of creep and post‐creep behaviors in adhesive joints.Higher creep load levels result in greater joint permanent deformations.Impact of higher creep load levels and durations on joint failure strength.Decreasing in the joint deformability and stiffness after creep. [ABSTRACT FROM AUTHOR]

The static friction behavior of an elastic–plastic spherical adhesive microcontact between a rigid flat and a deformable sphere under combined normal and tangential loading is studied by the finite element method (FEM). The contact between the sphere and the rigid flat is assumed to be full-stick, and the sliding inception is related to a loss of tangential stiffness. The intermolecular force between the rigid flat and the sphere is assessed by the Lennard–Jones (LJ) potential, which is applied to the sphere and the rigid flat by a user subroutine. The evolution of the adhesive force with tangential displacement in the full-stick condition is revealed. The results indicate that the increasing effect of adhesive energy on the static friction coefficient gradually diminishes with an increase in the adhesive energy and the external normal load. Finally, based on an extensive parametric study, an empirical dimensionless expression is obtained to predict the static friction coefficient of the spherical adhesive microcontact considering the intermolecular force. [ABSTRACT FROM AUTHOR]

Highlights Nowadays, inorganic fillers are widely used to enhance pressure‐sensitive adhesives (PSAs), but inorganic fillers have problems with poor compatibility and agglomeration. Furthermore, these types of PSAs usually have an antagonistic effect: as the shear performance improves, the initial tack decreases. This severely limits the application of PSAs. Herein, white carbon black (WCB) grafted with polyisoprene (PI) was prepared and used to enhance polyisobutylene‐based PSAs, and the optimal reaction conditions of grafting were explored. The shear and peel strength of PSAs all increase with the increase of the mass fraction of fillers. When the filler content is less than 10 wt%, the initial tack of PSAs increases. When the filler content exceeds 10 wt%, the initial viscosity of PSAs decreases, but it is still far higher than that of the unmodified WCB‐reinforced PSAs system. In addition, the rheological performances of PSAs were tested, further exploring the role of particle grafting in PSAs. PSAs reinforced with white carbon black grafted with polyisoprene were prepared. The optimal conditions for modified white carbon black have been determined. The grafting fillers have improved all the performance of PSAs. The grafting of fillers significantly reduces the antagonistic effect of PSAs. Rheology was used to explore the effect of filler grafting in the PSAs. [ABSTRACT FROM AUTHOR]

Hydrogels have emerged as promising candidates for biomedical applications, such as replacing natural articular cartilage, owing to their unique viscoelastic properties. However, sufficient mechanical properties, self‐healing ability, and adhesive nature are some issues limiting its application window. Here, a facile one‐pot synthesis of dual cross‐linked zinc‐coordinated copolymer hydrogels is presented. The network structure of the copolymer hydrogels is strategically developed via dynamic and reversible physical cross‐linking by Zn2+ ions and simultaneous covalent cross‐linking through a covalent cross‐linker viz methylene bisacrylamide. Fourier‐transform infrared (FTIR), X‐ray diffraction (XRD) scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis have thoroughly characterized the structure of the synthesized hydrogels. The introduction of Zn2+ offers dynamic and reversible complexation, leading to excellent mechanical properties and self‐healing features. Moreover, the percentage of the equilibrium water content of zinc‐coordinated copolymer hydrogel samples is comparable with that of natural articular cartilage. The Shear sliding study shows the dominant adhesive behavior of HGel‐Zn(NO3)2 sample compared to the parent HGel sample. This facile dual cross‐linked hydrogel, HGel‐Zn(NO3)2, with a combination of good mechanical properties, efficient self‐recovery, adequate water content, and favorable adhesive nature, seems very promising to mimic the articular cartilage. [ABSTRACT FROM AUTHOR]

In order to study the effects of adhesive, substrate material and ambient temperature on the mechanical properties of the adhesive joint, the quasi-static tensile mechanical properties of the single lap adhesive joint were studied. The results show that the bonding strength of epoxy resin adhesive is better than that of polyurethane adhesive, but the polyurethane adhesive shows good ductility. The differences of substrate materials would affect the strength of the adhesive joint. The plastic deformation at the lap end of aluminum substrate would accelerate of the failure process of adhesive layer, leading to the reduction of the joint strength. With the increase of temperature, the strength and stiffness of the adhesive joint decreases, but the decrease is related to the type of adhesive. It is mainly related to the glass transition temperature of the adhesive. In addition, the failure mode of the joint is affected by the ambient temperature. At high temperature, the joint is more prone to adhesive failure. The study provides a more comprehensive guidance for the application of single lap adhesive joint in the actual service environment of automobiles. [ABSTRACT FROM AUTHOR]

In this study, the shear strength and thermal properties of the adhesively bonded joints were investigated of adhesives reinforced with nanoparticles using carbon fiber-reinforced composite materials. The diglycidyl ether bisphenol A (DGEBA) was used as the epoxy resin. Single lap joint tests of 1% wt. Multi-walled carbon nanotubes (MWCNT) and 3, 5, and 7% wt. silicon dioxide (SiO2) nanoparticle-reinforced mixed adhesives were performed according to ASTM D5868 standards. The shear strengths of the mixed adhesives obtained by mixing at different ratios were compared with the epoxy resin. Upon conducting an analysis of the shear strengths of nanomaterials, results indicate that the incorporation of 1CNT + 3SiO2 in the nanomaterials showed the greatest improvement, with a 46% increase in shear strength. 1CNT + 5SiO2, 1CNT, and 1CNT + 7SiO2 showed increases of 32%, 14%, and 5%, respectively. The results of a tensile test indicate that pure epoxy exhibited a tensile strength of 5953 N, 1CNT, and 3SiO2, while the epoxy composite demonstrated a significantly higher tensile strength of 8738 N, along with an elongation of 0.72 mm. In addition, the morphology of fractured surfaces was examined by scanning electron microscopy (SEM). To investigate damage mechanisms, such as bridging, crack blunting, and branching of nanoparticles were observed. Characterization of epoxy resin and mixed MWCNT + SiO2 nanoparticles reinforced adhesives were also performed using Fourier infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). Nanoparticles are settled between polymer chains, improving polymer chains' motion and thermal properties. [ABSTRACT FROM AUTHOR]

Fabricating photonic crystals (PCs) with dynamic multi‐stimuli‐responsive structural colors, recordable colors, and self‐healable properties is significant for their emerging applications, yet remains a big challenge. Here, an all‐in‐one multifunctional PC (MFPC) film with outstanding mechanochromic, thermochromic, solvatochromic, color/shape‐recordable, self‐healable, and adhesive functions is designed and prepared by simply non‐close‐assembling silica particles into the unique 2‐[[(Butylamino)carbonyl]oxy]ethyl acrylate (BCOEA) followed by photopolymerization. The success is mainly due to the rational combination of non‐close‐packing structures and BCOEA's characteristics, including its urethane groups with numerous sacrificial hydrogen bonds, temperature‐dependent refractive index, swellable and deformable polymer network, as well as low glass‐transition temperature. The MFPC's hue and color saturation can be reversibly and dynamically modulated by strain/pressure/solvents and temperature, respectively, thereby realizing visually and spectrally sensing these stimuli. More interestingly, the color‐responsiveness combined with other functions endows MFPCs with fascinating emerging applications, including multilayer optical filters, inkless printing, reconfigurable multicolor patterns, stretching‐based anti‐counterfeiting, etc. This work offers a new perspective for designing next‐generation smart photonic materials and will facilitate their all‐round applications. [ABSTRACT FROM AUTHOR]

Switchable adhesives are materials of utmost importance due to their capability of having their adhesion/cohesion properties reversibly triggered upon stimuli, allowing on‐demand surface attaching/detaching. Still, several challenges mainly associated with complex uncontrolled chemical processes hinders their production. In this study, it is found that unexpectedly vinyl ethers are able to react with thiols in the presence of a catalytic concentration of base, which allows the preparation of well‐defined phase‐separated switchable adhesives. Indeed, these findings show that base‐catalyzed thiol‐acrylate and thiol‐vinyl ether are highly orthogonal, making the acrylate reaction faster. This is explored to react in the first stage thiols with acrylates in the presence of vinyl ethers to end‐cap all the oligomers with stable vinyl ethers and suppress undesirable disulfide formation. In a second stage the UV‐triggered thiol‐ene “click reaction” is carried out, forming the network. It is shown that the network prepared by this approach presents superior adhesion due to greater backbone length, a controlled crosslinking motif, and better‐defined microphase separation. Additionally, the adhesives made by this strategy are thermo‐switchable due to the temperature‐triggered base‐catalyzed thioether dynamic covalent character at 200 °C. Despite providing superior adhesive properties, the proposed technology endows scalable, thermo‐switchable, and O2‐resistant adhesives with huge industrialization potential. [ABSTRACT FROM AUTHOR]

Investigations on bonded stiffeners in steel and composite bridges Numerous bridges are in poor condition. In particular, resistance to plate buckling is a problem. Strengthening of buckling‐prone sections in steel bridges is often difficult due to non‐weldable steels and the additional notch effect from conventional joining techniques. The use of adhesives for fixing stiffeners allows material‐friendly reinforcement of buckling‐prone steel sections. Prior to practical application, numerous questions must be answered with regard to the detailing of the stiffeners, the stress on the adhesive layer due to inhibiting buckling, the load‐bearing capacity of the adhesive layer, the resistance to aging and fatigue. On the basis of numerical and experimental investigations, a simple fracture condition could be developed which allows a design of the adhesive layer's load‐bearing capacity. A sufficient stiffening effect of the bonded stiffener is given as long as the adhesive layer's load‐bearing capacity is sufficient. The aging and fatigue behaviour was investigated in basic tests. It was possible to define boundary conditions that enable resistance for a limited time, but there is still need for further research in this field. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the synthesis and characterization of an adhesive based on a glucose stabilized polyvinyl acetate homopolymer. Vinyl acetate monomer was stabilised onto liquid glucose using emulsion polymerization, and polymerization happened using potassium persulfate as an initiator. Here, the effects of adding liquid glucose as a stabiliser for adhesives were studied. Therefore, the current research examines whether liquid glucose, introduced at weight-based concentrations of 0.5% and 1.0%, is suitable as a colloid to produce PVAc adhesives for wood. By measuring viscosity, pH, contact angle, differential scanning calorimetry (DSC), and the pencil hardness test of films, the effect of adding liquid glucose as a colloid on physical, thermal, and mechanical properties was investigated. The shear strength of the PVAc homopolymers applied to wood using emulsions with varied liquid glucose concentrations was measured using a universal tensile machine. As the concentration of liquid glucose increased, the viscosity of the adhesives also considerably increased. Water resistance significantly rose when liquid glucose content increased, as was found by measuring the water contact angle. The use of liquid glucose increased the hardness of PVAc films, which was supported by the glass transition temperature. According to EN 204-205, the tensile shear strength with 1.0% of liquid glucose increased by 63.88% and 45.67%, respectively, over a pristine sample after 6 h of bonding in a dry environment and 24 h in a wet environment. The study's overall conclusion highlights the higher adhesion capability of PVAc emulsion-based adhesives stabilized by liquid glucose. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the in vitro influence of prior silane application on the microshear bond strength (μSBS) of Scotchbond Universal Plus to glass ceramic. Materials and Methods: Thirty blocks of lithium disilicate ceramic were etched with hydrofluoric acid for 20 s and distributed into Group 1 (no silane and no adhesive), Group 2 (adhesive), Group 3 (silane + adhesive). Three cylinders of resin cement were made on each ceramic block. Five blocks (n = 15 cylinders) were subjected to the μSBS test after 24 h, and the other five blocks (n = 15 cylinders) were tested after 6 months of water storage. Results: According to two‐way ANOVA, followed by Tukey's test, the means of μSBS (MPa), denoted by different letters, show significant differences (p < 0.05): after 24 h—Group 1 (31.7)B, Group 2 (43.3)A, and Group 3 (31.3)B; after 6 months—Group 1 (14.8)B, Group 2 (33.6)A, and Group 3 (30.3)A. After 6 months of storage, there was a significant decrease in μSBS for Groups 1 and 2, along with an increase in adhesive failures across all groups. Conclusions: Prior application of silane did not increase the μSBS between Scotchbond Universal Plus and ceramic, and there was degradation at the bond interface over time. Clinical Significance: Prior application of a silane agent is not necessary when using Scotchbond Universal Plus for bonding to glass ceramics. Regardless of the prior application of silane, there is degradation at the bond interface over time. [ABSTRACT FROM AUTHOR]

Adhesives play an important role in modern society's production and daily life. Developing robust and sustainable adhesives remains a great challenge. Here we report a sustainable epoxy-vitrimer adhesive with high adhesive strength (about 10 MPa) and reusability (82% strength after 3 times). This adhesive can be fabricated from commercially available products through a straightforward hot-pressing method without the need of solvents. The adhesive process is also simple, requiring only 30 min at 180 °C. In addition, the vitrimer adhesive has the advantages of both erasability for reuse and excellent water resistance. This work provides a facile strategy to fabricate high-strength adhesive that ensures reusability, recyclability, low cost of raw materials, and simple processing technology. Simultaneously, it expands the range of potential applications for epoxy vitrimers. [ABSTRACT FROM AUTHOR]

This experimental study was performed to assess whether applying a metal primer containing 10-MDP multiple times affected the repair shear bonding ability of base metal alloys to resin composites. Ten base metal alloys were randomly assigned to each group in the manner described, following multiple applications of a metal primer (Clearfil Ceramic Primer Plus), namely one to five applications, and no primer application as a negative control. On the specimens' prepared surfaces, the resin composite was pushed into the mold and then light-activated for 40 s. The bonded samples were kept for 24 h at 37 °C in distilled water in an incubator. The shear bond strength was determined using a universal testing device. A stereomicroscope was used to determine the debonded surface. The one-way ANOVA and Tukey's test were implemented to statistically analyze. The lowest shear bond strength was found in group 6 (6.14 ± 1.12 MPa), demonstrating a significant difference (p = 0.000) when compared to groups 1 to 5. The shear bond strength of group 3 was highest at 21.49 ± 1.33 MPa; there was no significant difference between group 3 and groups 4 and 5 (20.21 ± 2.08 MPa and 20.98 ± 2.69 MPa, respectively) (p = 0.773, p = 1.000, respectively). All fractured specimens in groups 1, 2, and 6 were identified as adhesive failure. Groups 3 and 4 exhibited the highest percentage of mixed failures. To achieve the repair shear bonding ability of base metal alloys to resin composites, the sandblasted base metal alloys should be coated with three applications of a metal primer before applying the adhesive agent. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effects of dental bleaching on the immediate shear bond strength (SBS) of composite to enamel. Different bleaching methods and time intervals between bleaching and composite restoration were examined. A total of 45 enamel specimens were divided into three groups (n = 15) based on the applied bleaching protocol: in‐office (A), at‐home (B), and unbleached control (C). Groups A and B were then subdivided into three time intervals until bonding: 1, 3, and 7 days. The composite was bonded to enamel using self‐etch adhesive technique and submitted to SBS testing. The enamel surface and adhesive interface were observed under scanning electron microscope (SEM). The highest average SBS was measured in the control (unbleached) group (31.1 ± 3.4). A significant difference in SBS was found between the control and in‐office bleaching (p <.001), as well as between control and at‐home bleaching (p =.034), while the difference between in‐office and at‐home bleaching methods was insignificant. In relation to the waiting period, a significant reduction in SBS (p <.001) was found 1 day post‐bleaching. The weakest marginal sealing to enamel under SEM was observed also 1 day after bleaching. Both bleaching methods significantly reduced the SBS of composite to enamel, especially immediately after the bleaching procedure. Reduction in SBS is temporary and 3‐day waiting period seems to be sufficient to reverse the adverse effects of bleaching. Research Highlights: SBS of composite to enamel is significantly reduced by bleaching procedures, especially immediately after bleaching.The reduction in SBS is temporary and reversible by delaying the restoration for a minimum of 3 days. [ABSTRACT FROM AUTHOR]

The goal of present work is to create a polymer base for compounds, binders for materials with different fillers and adhesives. The article presents the results of studies of the physical and mechanical characteristics of urethane-containing elastomers based on epoxy urethane oligomers. The reaction proceeded in two stages and included the formation of oligodiisocyanate. Based on them, elastomers with urethane-hydroxyl hard segments were synthesized. Methyl nadic anhydride and an oligodiendiol with terminal carboxyl groups were used as hardeners. The deformation-strength properties of elastomers, as well as the strength of the adhesive joints for aluminum and steel, were studied. Using an oligomer with carboxyl groups as a hardener lowers the glass transition temperature of elastomers and improves their deformation characteristics. The glass transition temperature of the samples was determined using a differential scanning calorimeter. The physical and mechanical tensile characteristics of the obtained materials were determined on a universal testing machine. Elastomers cured with an oligomer containing carboxyl groups can be used as a polymer base for compounds and binders for materials with different kinds of fillers due to their low modulus and high deformation properties. Elastomers cured with methyl nadic anhydride may find use as adhesives. [ABSTRACT FROM AUTHOR]

B. mori silk has been extensively utilized to create Regenerated Silk Fibroin solutions (RSF) for a wide range of technological applications, including tissue engineering, drug delivery, biomaterials, and adhesives. In this study, an RSF‐dopamine (DA) composite is introduced that yields easily deployable hydrogel fibers possessing adhesive properties that can be released on demand to capture and retrieve loads from a distance. The RSF‐DA serves as an artificial dope, combining the functional attributes of silk fibroin (i.e., hydrogel formation) and dopamine (i.e., adhesion) to instantly generate adjustable hydrogel fibers displaying a sticky behavior. The mechanical strength and adhesive characteristics of this material are assessed using tensile and lap‐shear tests. Furthermore, the possibility of tuning these properties is demonstrated by adding chitosan (Ch) and borate ions (BB), leading to remarkable mechanical and adhesive performances up to 107 MPa and 280 kPa, respectively, which allows the retrieval of objects from the ejected structure. This process can be finely tuned to achieve a controlled fabrication of instantaneously formed adhesive hydrogel fibers for manifold applications, mimicking living organisms’ ability to eject tunable adhesive functional threads. [ABSTRACT FROM AUTHOR]

Adhesives play a crucial role in modern everyday applications, prompting a growing environmental consciousness regarding their source, composition, utilization, and disposal. Sustainability concerns are frequently generated due to the complex or energy‐intensive manufacturing processes in the production of conventional water‐based adhesives. Here, a coacervate‐based snail‐inspired solvent‐free adhesive (SFA) is engineered by strategically modulating electrostatic interactions and molecular entanglement of two polypeptides under environmentally friendly conditions. The SFA has a record‐breaking adhesion strength of 28 MPa on ceramics, setting a new standard for bio‐based adhesives. The SFA demonstrates robust adhesion performance across a wide temperature ranging from −150 to 300 °C and allows for reusability without compromising adhesion properties. Moreover, it can be easily removed using a non‐toxic alkaline solution. The study presents a promising opportunity for developing high‐performance, reusable adhesives made from renewable materials suitable for industrial applications, relics repair, and even spacecraft processing. [ABSTRACT FROM AUTHOR]

Colloidal polymers, and in particular aqueous polymer dispersions, are widely used in commercial applications such as coatings and adhesives. Historically, the solvent resistance and mechanical properties of these systems have been improved by covalently crosslinking the polymer chains after drying. More recently, work has been directed toward replacing this covalent crosslinking, which typically involves highly reactive functional groups, by physical crosslinking through the use of supramolecular interactions. While conceptually similar to the use of covalent crosslinking, physical crosslinking has a unique influence on the rheology of the polymer, which leads to substantial differences in the development of mechanical strength during drying, as well as the mechanical properties of the final polymer film. In this perspective, the advantages and challenges of this approach are outlined, and an outlook for future research in this direction is provided. [ABSTRACT FROM AUTHOR]

Cell therapy strategies hold great promise for nucleus pulposus (NP) regeneration and intervertebral disc degeneration (IVDD) treatment. However, their therapeutic efficiency is compromised by the anoikis of administered cells and the harsh environment in degenerated intervertebral discs (IVD). Inspired by the ability of nucleobases to form multiple H‐bonds, a nucleobase‐driven self‐gelling strategy is proposed for the incorporation of nucleobases (e.g., thymine) into hyaluronic acid (HA) chains to trigger gel formation through enhanced intermolecular H‐bond interactions. An aqueous solution of a thymine‐modified HA (HAT) supramolecular polymer is shown to exhibit self‐gelation behavior, injectability, tissue adhesion, and hydration capacity (comparable to that observed in the NP tissue of a 25‐year‐old adult). These characteristics enable the injection and filling of the HAT hydrogel system in the IVD, integration of the separated NP tissues, restoration of the biomechanical functions of the degenerated IVD, and securing of the encapsulated cells in the NP site. Manganese dioxide (MnO2) nanoparticles incorporated into the HAT system (HATMn) regulate oxidative stress and the hypoxic microenvironment in degenerated IVD, ensuring the viability of the encapsulated cells. The 12‐week in vivo study results demonstrate that the administration of the MSCs‐laden HATMn system (HATMn‐MSCs) effectively restores the structure and function of degenerated IVD. [ABSTRACT FROM AUTHOR]

Starch is one of the oldest adhesives, and has been utilised for a variety of applications, including as a consolidant for artworks and archives, after cooking. Although widely available, cost-effective, and versatile it has limitations such as large particle size, which makes it challenging for the adhesive to penetrate deeply into objects. Attempts to increase the concentration of starch adhesives for enhanced strength often lead to increased viscosity, hindering penetration and causing an undesirable film on the surface. Achieving a workable consistency often leads to reduced adhesive power. An approach to using nanosized starch as a binder for paper and cellulose-based objects is presented. Starch nanoparticles (SNPs) from wheat, rice, maize and waxy maize were successfully synthesised using a 'top-down' approach that is facile as well as energy efficient. Size distribution measurements indicate most particles to be less than 50 nm, smaller than the pore size of most historic papers. SNPs could make a better sizing adhesive than traditionally-made starch paste, and they are also a green alternative to a variety of chemically formulated, organic solvent-based adhesives. The compatibility, non-toxicity, and biodegradability of starch remained uncompromised during the modification. [ABSTRACT FROM AUTHOR]

This paper outlines a research project on the use of wood tar as adhesive for architectural stone repairs. Tar was identified as having been used in medieval repair techniques on Stavanger cathedral in Norway, as well as on several other medieval cathedrals in England and Germany. The hypothesis is that a complex adhesive mixture based on wood tar was manufactured and strategically employed by medieval artisans in northern Europe as stone repair material. Given that such repairs have withstood centuries of wear, there must have been extensive material knowledge and awareness of the complex requirements of structural adhesives. These historic tar repairs created the impetus for a research project, the aim of which is to rediscover the lost medieval art of traditional stone repair using wood tar adhesives, recreate the historic adhesive and repurpose it for modern conservation practice. By reintroducing traditional wood tar adhesives based on natural renewable source materials, we could potentially reduce dependence on synthetically manufactured adhesives. Thus, newly-discovered medieval techniques which have successfully lasted centuries will be drawn on to help solve the limited selection of suitable adhesives for stone conservation, contributing to future preservation of stone architecture and the built heritage environment. [ABSTRACT FROM AUTHOR]

Purpose Adhesive remnants removal is the last key step influencing orthodontic treatment outcomes. Four different clearance methods (CM) of orthodontic adhesive were evaluated to determine, which achieved the smoothest enamel surface in the shortest time. Materials and Methods 75 intact premolars extracted for orthodontic purposes were included, sixty had an orthodontic bracket bonded and subsequently removed, and fifteen served as the control group. Four CMs were used to clear the tooth surface of 15 premolars each: carbide bur (CB), carbide bur with titanium nitride surface treatment + fine carbide bur (CBCB), glass fiber-reinforced composite instrument (GFCB), zirconia bur + glass fiber-reinforced composite bur (ZBCB). The processing time was recorded. In ten premolars from each group, the enamel surface was evaluated by atomic force microscopy estimating mean roughness (Ra), roughness profile value (Rq), and roughness depth (Rt). Enamel Damage Index (EDI) was assessed with a scanning electron microscope on 5 remaining premolars. Results Significant differences were observed in all evaluated parameters - Ra (p<0.0001), Rq (p<0.0001), and Rt (p<0.0001). GFCB exhibited the smoothest surface in all parameters. The lowest EDI exhibited teeth treated by GFCB, however, the differences were not significant. Working with GFCB took the longest time (mean 116 s), and the shortest with CBCB (mean 49 s). Conclusion Using CB is the fastest clearance method, but the enamel surface roughness was highest. Clearing with a set of instruments CBCB proved to be a fast method with satisfying remaining enamel roughness. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of fracture behavior in laminated composites using a combination of surface treatments and nanomaterial incorporation. The adherent material used is glass fiber-reinforced polymer (GFRP), and the surface treatment was applied to the GFRP surface. The adhesive used in the joints is an epoxy-based adhesive, which was reinforced with Multi-Walled Carbon Nanotubes (MWCNTs) to improve its mechanical properties. Initially, mechanical sanding techniques were explored, revealing significant improvements of 55% in fracture energy and 38% in load-bearing capacity with optimal 240-grit sanding. Subsequently, MWCNTs were introduced at varying weight percentages (0.1%, 0.3%, and 0.5%) into the adhesive. This combined approach aimed to synergistically examine the impact of surface pretreatments and nanoparticle integration on the fracture behavior of the GFRP joints. Results highlight the potential for fracture resistance and enhanced load-carrying capabilities in reinforced specimens, with maximum load and fracture energy improvements of up to 92% and 50%, respectively, compared to unreinforced specimens and those subjected solely to sanding treatments. Moreover, the shift in failure mode from adhesive failure to cohesive substrate failure was observed and is attributed to the enhanced bonding area created by the 240-grit sanding and the increased fracture resistance from the incorporation of 0.3 wt% MWCNTs. The inclusion of MWCNTs provides additional toughening mechanisms such as crack bridging and pull-out, which significantly increase the fracture energy. This comprehensive investigation underscores the intricate interplay between mechanical preparation and nanomaterial incorporation in significantly improving the performance of laminated composites.Highlights: Synergistic effect of optimal surface preparation and MWCNT incorporation on GFRP joints. Improvements of up to 92% in maximum load and 50% in fracture energy with 0.3 wt% MWCNTs in epoxy adhesive and 240-grit sanding. Shift from adhesive failure to cohesive substrate failure due to combined surface sanding and MWCNT reinforcement. [ABSTRACT FROM AUTHOR]

Through raw material screening,mix ratio design and test,developed a new type of adhesive for exterior wall insulation decorative board with high bond strength,long operational time,anti -freezing and anti -seepage,green environmental protection,safety and non-toxic,simple construction and long service life. The content of polycarboxylic acid superplasticizer is 0.05%,the content of cellulose ether is 0.20%-0.25%,heavy calcium and fly ash can replace part of cement,the content is about 7%. All the performance indexes of the adhesive produced can meet the technical requirements and construction requirements,and the engineering application is good. [ABSTRACT FROM AUTHOR]

Purpose: Stitching is the traditional method of creating seams using needles and threads. However, this is not useful for waterproof breathable garments as needle holes allow water to penetrate inside the garment, compromising its functionality. This study aims to investigate different techniques for covering the needle holes formed during stitching to achieve a seam that is waterproof, durable and functionally effective. Design/methodology/approach: This study investigates different methods to cover needle holes formed during stitching with the help of seam tape, seam grip adhesive and fuser thread. The emphasis is on evaluating the seam characteristics, including seam strength, seam efficiency, puckering, bending stiffness and resistance to water penetration. Statistical analysis involves the use of the Shapiro–Wilk test, Levene statistic, one-way ANOVA and Tukey's HSD and Tamhane post-hoc tests. Findings: The experimental results suggest that seam tape is effective in enhancing water resistance, seam strength and seam efficiency, but it contributes to stiffness and aesthetically degrades seams due to increased puckering. Meanwhile, the use of fuser thread presents an alternative, exhibiting improved waterproof properties compared to regular stitching. It offers more flexibility and less puckering compared to seam tape. Originality/value: This study contributes novel insights by shifting the focus from alternative seaming methods such as bonding and welding, to enhancing traditional stitching for waterproof seam construction. While prior research primarily explored alternatives to stitching, this study uniquely addresses the effectiveness of different techniques in covering needle holes to achieve waterproof seams. The findings provide valuable information for enhancing the functionality of stitched seams in the production of waterproof breathable garments. [ABSTRACT FROM AUTHOR]

Conductive hydrogels with adjustable mechanical properties, good flexibility, and high sensitivity are considered to be promising and reliable materials for next-generation wearable devices. To enhance the mechanical properties of hydrogels, double-network (DN) strategy was always brought in hydrogel preparation. However, chemical crosslinks in DN hydrogel will lead to lack self-recovery properties and biocompatibility. Thus, we developed a fully physical crosslinked DN gel by a large quantities of metal chelation and hydrogen bonds by adding ions in mixture of gum arabic (GA) and copolymer polymerized by acrylamide (AM), acrylic acid (AA), and N-Methylolacrylamide (NMAM). This hydrogel (we named GPFE gel) exhibited excellent mechanical properties such as superb tensile strain (2340%), tensile strength (198 KPa), and high toughness (1.59 MJ/m3). Besides, benefiting from the large number of hydrogen bonds brought by the introduction of EG, GPFE gel also showed intriguing self-healing property (97.0% healing efficiency after 2 h), adhesive property (both in the air and underwater), and environmental stablity (could be used normally at –20 °C). Wearable flexible sensors prepared directly from GPFE gel can sensitively monitor both daily activities and slight physiological movements, exhibiting high sensitivity (GF = 2.16) and a wide strain detection window (to eleven times the original length). Therefore, the prepared GPFE gel as a high-performance wearable flexible sensor in this study shows tremendous potential applications in a complex environment. Highlights: The GPFE gel was a fully physical crosslinked double-network (DN) hydrogel with excellent mechanical properties. The addition of GA to the GPFE gel served to render it transparent while simultaneously conferring upon it the desirable properties of self-adhesion, both in the air and underwater. The GPFE gel exhibited an intriguing self-healing property, with 97.0% healing efficiency observed after 2 h. The GPFE gel demonstrated environmental stability, with no adverse effects observed when used at temperatures as low as –20 °C. The GPFE gel exhibited high sensitivity (GF = 2.16) with a wide strain detection window (to eleven times the original length). [ABSTRACT FROM AUTHOR]

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Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectivesTo solve the problem of applying thick carbon fiber laminates in naval architecture and marine engineering, this paper proposes a thick plate structure composed of thin carbon fiber laminates with reinforcing ribs and core material in the middle.MethodsFirst, based on the theory of continuous damage mechanics, two-dimensional Hashin failure criterion and cohesive element technology, a finite element analysis model of a combined thick plate is established. Second, the bending performance of the combined thick plate in different directions is compared and analyzed. Next, the progressive damage process of the adhesive layer and carbon fibre-reinforced polymer (CFRP) is analyzed to investigate the failure behavior and mechanisms of the combined thick plate during the bending process in the direction perpendicular to the stiffeners. Finally, the influence of adhesive strength on the damage behavior of the combined thick plate is discussed. ResultsThe results indicate that the bending stiffness of the combined thick plate is higher in the direction perpendicular to the stiffeners compared to the parallel direction. During the bending process perpendicular to the reinforcing rib direction, the adhesive layer at the interface between the rib plate and panel is the first to suffer damage; it rapidly expands under shear force, ultimately forming a mixed failure mode where interface failure and panel 0° ply fiber tearing promote each other. When the adhesive strength is low, the adhesive layer breaks first; and when the adhesive strength is high, the laminates break first. The adhesive layer mainly bears shear action under Types II and III tearing modes, and the shear stress in the direction of the reinforcing rib is the primary cause of initial damage to the adhesive layer. ConclusionsThis study reveals the damage behavior of a new-type composite thick plates during bending perpendicular to the stiffener direction, thereby providing technical references for the promotion and application of thick composite plates with reinforcing ribs and core material in the middle in major load-bearing structures in the fields of naval architecture and marine engineering.

The acceptable wear behavior of nanostructured bainitic steels has enhanced their potential to be industrialized, and their applications in the automotive industry. This study focused on the wear behavior of the high-strength nanostructured bainitic steel containing 3.5 wt% aluminum (low-cost and low-density) to assess the dominant sliding wear mechanism and the correlation between the microstructure and applied load on the sliding wear resistance. A pin-on-disk tribometer was used to evaluate dry sliding wear behavior, and the SWR was computed by weighing the specimens. To identify the wear mechanism, the worn surfaces and cross-sections were analyzed using XRD, FESEM, and EDS. The results showed that the retained austenite volume fraction and carbon content of austenite (the stabilizer of the retained austenite) of high-strength nanostructured bainitic steels are not the only determinants of wear behavior. Indeed, the thickness of bainitic ferrite plates (strength source) is the major parameter affecting wear resistance. An increase in the Vαb/tαb ratio due to a decreased austempering temperature reduced the SWR and enhanced wear resistance. Moreover, the change from a normal load of 50 N to a load of 150 N changed the dominant wear mechanism from oxidative to adhesive. Also, increasing the isothermal transformation temperature and applied load by increasing the thickness of the tribological-transition-zone (TTZ) causes a decrease in sliding wear resistance. In summary, the formation of a thin TTZ due to the increase in the Vαb/tαb ratio is the main reason for the improvement of the wear resistance of the austempered sample at the lowest temperature (250 °C).

This study shows that the progressive adhesion of weld material to the tool in friction stir welding AA 2024-T3, up to tool saturation, brings about a decrease in power consumption until a plateau is reached. The cause of this behavior is the hindering of the stirring action of the tool due to the material accumulated on it. The built-up material changes the nature of the tool/material interaction and then the friction condition at their interface. The direct consequence is a decrease in the shearing strain and therefore in the heat generated by friction. Bits of this adhering material break off from the tool at intervals. Macro and micro detachments are identified. Micro-detachments happen continuously at small periodic intervals and produce vibrations. The amplitude of these vibrations increases in all their characteristic spectral components up to tool saturation. Macro-detachments generate oscillations in power consumption and leave galling on the weld bead. [ABSTRACT FROM AUTHOR]

In this study, the crosslinking agent citric acid (CA) is added to liquid glucose (LG)-polyvinyl alcohol (PVA) blend-based wood adhesives to improve their mechanical and thermal properties. The effect of crosslinking has been investigated using various analytical techniques, including viscosity, water contact angle, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Several variables were investigated for their effects on performance characteristics, including glass transition temperature, pencil hardness, and tensile strength. Increasing the amount of CA and the content of LG were among these factors. The crosslinked blend-based films increased in pencil hardness value and showed less hydrophilic behavior in the water contact angle test. It is expected that nucleophilic hydroxyl groups in LG and PVA will react with free carboxylic groups to form crosslinks. By analysing FTIR spectra, it has been demonstrated that CA and the LG-PVA mixture interact. After 24 h of bonding for two distinct ratios of PVA to LG (i.e., 25:5 and 20:10), the lap shear bond strength for the wood substrates bonded with the modified blend increased by 250% and 263% for 0.3 wt% CA, respectively. Blends with 0.5 and 0.7 weight% CA showed a predominately plasticizing tendency because CA that has not been reacted acts as an external plasticizer. The glass transition temperature (Tg) and increase in viscosity were indicators of the reaction's consequences due to the acidic pH. The newly developed crosslinked LG-PVA blend-based wood adhesive showed better mechanical and water resistance properties when compared to conventional LG-PVA blend-based wood adhesives. [ABSTRACT FROM AUTHOR]

To date, no consensus exists regarding the management of enamel infractions (cracks and craze lines), which may be associated with sensitivity. Two clinical cases are presented on the management of enamel infractions using a modified erosion-infiltration protocol for resin infiltration. Initially indicated for the treatment of early caries lesions, Icon (DMG) low-viscosity resin infiltrant has also been used to mask unesthetic developmental defects of enamel in anterior teeth. Treatment using this modified infiltration protocol immediately eliminated tooth sensitivity associated with the enamel infractions. Resin infiltration has the potential as a minimally invasive and effective treatment for the management of sensitivity associated with enamel infractions. [ABSTRACT FROM AUTHOR]

Background/purpose: The dental adhesive market is constantly evolving to meet the demands of dentists and patients, but new products and upgrades should be rigorously evaluated before being used in clinical practice. This study investigated the physicomechanical properties and dentin bonding efficacy of a newly upgraded universal adhesive compared to its predecessor. Materials and methods: Twenty-four molars were divided into four groups (n = 6/group) based on adhesive (new vs. predecessor) and application mode [self-etch (SE) vs. etch-and-rinse (ER)] for evaluating their dentin microtensile bond strength (μTBS), failure pattern, and bonding interface. Additional thirty-six molars’ crowns were perpendicularly sectioned to obtain flat mid-coronal dentin discs. The opposing dentin surfaces of each disc received contrasting treatments (new/predecessor adhesive applied in SE/ER mode), resulting in six interventions. The bonded discs (n = 6/intervention) were used to assess the adhesives’ survival probability employing a double-sided μTBS test. The other physicomechanical properties examined were adhesives’ oxygen inhibition layer (OIL), viscosity, hardness, elastic modulus, degree of conversion (DC), and in-situ DC. Results: Both adhesive versions showed similar μTBS (P > 0.05), failure pattern (P > 0.05), and survival probability (P > 0.008). ER mode promoted resin tag formation and exhibited a slender adhesive layer for both adhesives. The newer adhesive version showed a thinner adhesive layer in general with narrower OIL (P

Abstract Background Clinicians often utilize both flowable and packable composites concurrently in bonding fixed retainers. Thus, this study aimed to assess the synergistic effect of these composites in the bonding process. Methods This in vitro study divided specimens into three groups: flowable composite (nano-hybrid, Tetric N-Flow, Ivoclar Vivadent), packable composite (nano-hybrid, Tetric N-ceram, Ivoclar Vivadent), and combined use of flowable and packable composite. Shear bond strength (SBS), adhesive remnant index (ARI), and wire pull-out resistance were compared among the groups. Statistical analyses were conducted using ANOVA and Tukey tests to compare study groups. Additionally, Chi-square and Kruskal-Wallis tests were employed to analyze the ARI index among the groups. Results ANOVA results indicated no statistically significant differences among test groups (P = 0.129) regarding SBS. However, a significant difference existed between flowable and packable composite groups (P = 0.01) regarding ARI scores. Among the study groups, flowable composite exhibited the highest frequencies of ARI scores of 1 and 2, whereas packable composite showed the highest frequency of ARI scores of 0. The combined group had higher frequencies of ARI scores of 0 and 1 compared to the flowable composite. The wire pull-out test revealed that the combined application of flowable and packable composite resulted in significantly lower detachments compared to the packable composite alone (P = 0.008). However, no significant differences were observed in the comparisons between the flowable-packable (P = 0.522) and combined-flowable (P = 0.128) groups. Conclusion The combined use of flowable and packable composites for fixed retainers demonstrated adequate shear bond strength and ideal ARI scores, suggesting it as a suitable adhesive system for bonding orthodontic fixed retainers.

Fragment reattachment for crown root fractures has become a routinely employed treatment modality with the advancements in adhesive dentistry. Among the majority of documented dental trauma cases, this specific fracture type is one of the most prevalent and difficult fracture kinds. Due to its complexity, these fracture kinds are often not computationally modelled. Moreover, there is a lack of literature to understand the effect of different adhesive materials, used to re-attach this particular fracture, on traumatic injuries. In our work, 3D models of the permanent maxillary central incisor tooth were developed using cone beam computed tomography image of a patient. This model was systematically modified to represent a prominent crown root fracture and subsequently re-attached computationally using three different adhesives. A biting force and a traumatic load were applied, and the induced stresses were studied across the healthy and treated tooth models and compared for three different adhesives used for re-attachment of fractured fragments. Tooth reattached with resin adhesive performed better in all the loading conditions that were considered in the study as compared to flowable composite and resin cement.

Dental fluorosis, a condition characterized by enamel hypoplasia caused by excessive fluoride intake, can potentially affect the adhesion of dental materials. This systematic review aimed to assess the influence of dental fluorosis on shear bond strength (SBS) and to provide clinical recommendations. A comprehensive search of electronic databases was conducted, followed by a rigorous selection process to include relevant in vitro studies. The quality of the included studies was assessed and data were extracted for analysis. Based on these findings, it is recommended to consider alternative bonding techniques or to use specific dental materials for fluorosis-affected teeth. Further research is needed to elucidate the mechanisms underlying the potential impact of dental fluorosis on shear bond strength and develop more targeted clinical strategies.

Recently, renewable bio‐based materials have received more and more attention due to environmental issues such as global warming and ecosystem destruction. In the present work, a series of isosorbide‐based bioelastomers poly(isosorbide carbonate‐co‐butanediol aliphatic esters)s (PICBAs) are synthesized by a facile and economical two‐step melt polycondensation. Due to the slightly self‐crosslinking reaction of isosorbide, PICBAs exhibit excellent tensile strength and self‐healing ability, the mechanical properties of PICBAs can recover over 95% after 48 h under room temperature. In addition, PICBAs can stick different substances, such as glass, rubber, plastic, and stones, and show better adhesive performance than 3M commercially available double‐sided tape. Consequently, isosorbide‐based bioelastomers PICBAs are of great potential to be used as environmentally friendly pressure‐sensitive adhesives (PSA) in the future. [ABSTRACT FROM AUTHOR]

The self‐heating‐induced temperature rise in the adhesive layer under fatigue loading plays a significant role in influencing the fatigue behavior of riveted‐bonded hybrid joints in aluminum‐carbon fiber reinforced polymer composite structures. This study aims to investigate the impact of the self‐heating effect on the fatigue life of such hybrid joints. Experimental analysis was conducted to explore the interrelationships between temperature evolution and fatigue behavior at varying frequencies, adhesive thicknesses, and loading levels. Additionally, a theoretical model for predicting self‐heating temperature rise in hybrid joints with different parameters was developed. Results show that the self‐heating effect is notably affected by loading frequency, loading level, and adhesive thickness. The theoretical model accurately captures temperature variations and predicts critical frequencies for hybrid joints under different loading levels, which are identified as 10, 8, 3, and 1 Hz for loading levels of 35%, 40%, 50%, and 60%, respectively. Critical adhesive thicknesses ranging from 0.5 to 1 mm were also determined. Furthermore, the study predicts the fatigue life at specific self‐heating temperatures with an average error within 4%, offering valuable theoretical insights for evaluating the fatigue safety performance of hybrid joints and facilitating optimization strategies. Highlights: The interrelationship between the self‐heating effect and fatigue behavior was revealed.Quantitative influences of main process parameters on the self‐heating effect were discussed.A self‐heating temperature rise model considering process parameters was developed.The critical frequency and adhesive thickness of the hybrid joint were determined. [ABSTRACT FROM AUTHOR]

Objectives: The first aim of this study was to determine whether there is a difference in degree of conversion (DC) of touch-cure cements polymerized by self-curing with adhesive or dual-curing under reduced light. The second aim was to compare interfacial adaptation of zirconia restoration cemented using touch-cure cements self-cured or dual-cured by reduced light. Methods: The DC of touch-cure resin cements with adhesive was measured continuously using Fourier transform infrared spectrometry. Experimental groups differed depending on touch-cure cement. Each group had three subgroups of polymerization method. For subgroup 1, the DC was measured by self-curing. For subgroups 2 and 3, the DCs were measured by dual-curing with reduced light penetrating 3 mm and 1 mm zirconia blocks, respectively. For interfacial adaptation evaluation, Class I cavity was prepared on an extracted third molar, and zirconia restoration was fabricated. The restoration was cemented using the same cement. Groups and subgroups for interfacial adaptation were the same as those of the DC measurement. After thermo-cycling, interfacial adaptation at the tooth-restoration interface was evaluated using swept-source optical coherence tomography imaging. Results: The DC of touch-cure cement differed depending on the measurement time, resin cement, and polymerization method (p < 0.05). Interfacial adaptation was different depending on the resin cement and polymerization method (p < 0.05). Conclusion: For touch-cure cement, light-curing with higher irradiance presented a higher DC and superior interfacial adaptation than light-curing with lower irradiance or self-curing. Clinical relevance: Although some adhesives accelerate the self-curing of touch-cure cement, light-curing for touch-cure cement is necessary for zirconia cementation. [ABSTRACT FROM AUTHOR]