Tensile Bond Strength Research Articles

The effects of different silicatization and silanization protocols on the bond durability of resin cements to new high-translucent zirconia.

The aim of this study was to assess the influence of different silicatization protocols with various silane treatment methods on the bond performance to high-translucent zirconia. High-translucent zirconia specimens were assigned to five groups according to mechanical surface pretreatment: as-sintered (Con), 0.2MPa alumina sandblasting (AB2), tribochemical silica coating (TSC), 0.2 and 0.4MPa glass bead air abrasion (GB2) and (GB4). Each group was subjected to 4 different cementation protocols: Panavia SA Universal (SAU), Panavia SA plus (SAP), silane + SAP (S-SAP), and Universal adhesive + SAP (U-SAP). Tensile bond strength (TBS) was measured after 24h and 10,000 thermocycling (TC). Surface topography, surface energy, and elemental composition of the abraded zirconia surface analyses were completed. TBS data was analyzed using the Weibull analysis method. Surface roughness and surface energy were compared by one-way ANOVA analysis of variance (α = 0.05). After 24h, higher TBS was achieved with all cementation protocols in AB2 and TSC, also, in GB2 with all protocols except U-SAP, and in GB4 with SAU and S-SAP. After aging, GB4/S-SAP, GB2/S-SAP, AB2/U-SAP, and TSC/S-SAP showed the highest bond strength. GB groups showed the lowest surface roughness and highest surface energy. Glass bead abrasion achieved the durable bond strength to high-translucent zirconia using a separate silane coupling agent while altered surface chemistry, surface energy, and roughness without effect on morphology. Glass bead air abrasion is an alternative to alumina sandblasting and tribochemical silica coating and improves bond strength to high translucent zirconia.

Various Mechanical Properties of Denture Liners Combined with Zirconium Oxide Nanoparticles

Debonding from the denture base, poor resistance to tearing, and increase in hardness are some of the problems with denture liners. This research purposed to analyze the changes in mechanical characteristics of the tissue conditioner and the denture liner concerning the interaction of the material with the zirconium oxide nanoparticles (ZrO2-NPs). The surface functionalization of ZrO2-NPs was done using a silane coupling agent as a modifier for better integration of them into the denture liners. Then, they were added into acrylic- and silicone-based denture liner in two different percentages (0.5% and 1% by weight; respectively). The performed tests were tear strength, tensile bond strength, and hardness (Shore A). 0.5% and 1% of ZrO2-NPs added tissue conditioner test groups displayed statistically significantly lower tensile bond strength values than tissue conditioners without ZrO2-NPs (p < 0.001). However, the tensile bond strength results of all subgroups for soft denture liner were statistically similar (p = 0.239). In all of the test groups of tissue conditioner and soft lining material, the highest tear strength values were obtained in 0.5% ZrO2-NPs added test groups (tissue conditioner; 0.58±0.11 N and soft denture liner; 4.10±0.58 N). The shore A hardness results of both tested groups determined no meaningful differences (p = 0.100). All subgroups of the tested silicone-based denture liners had satisfactory and clinically adequate bonding strength to the base of the prosthetic.

Evaluation of Helium Plasma Surface Modification on Tensile Bond Strength of Denture Base Materials: A Scanning Electron Microscope Study

The purpose of this study was to compare the effect of helium plasma treatment on tensile bond strength between polymethylmethacrylate and soft liner material. For the tensile test, acrylic samples (30 × 10 × 10 mm3; n = 100) were prepared. Acrylic samples were divided into five surface groups (n = 10/group) and treated by different concentrations of helium plasma: G I: Control group (untreated), G II: 100% Helium plasma-treated group, G III: 90% Helium plasma-treated group, G IV: 85% Helium plasma-treated group, G V: 80% Helium plasma-treated group. After plasma treatment, the soft liner was processed between two acrylic resin blocks according to the manufacturer’s instructions and polymerized. The surface properties were evaluated by scanning electron microscopy and atomic force microscopy. All samples were submitted to a tensile test using a universal testing machine. After failure, the surface properties were evaluated by stereomicroscope. One-way analysis of variance was used to compare the groups. p < 0.05 value was considered statistically significant. While the highest mean tensile bond strength value was obtained with the G III (1.56 ± 0.13 MPa), the lowest value was observed with the G I (0.95 ± 0.2 MPa). In addition, it was observed that the surface roughness increased the most in G III.

Performance of sustainable self-compacting fiber reinforced concrete with substitution of marble waste (MW) and coconut fibers (CFs)

Self compacting concrete (SCC) is special type of concrete which is highly flowable and non-segregated and by its own mass, spreads into the formwork without any external vibrators, even in the presence of thick reinforcement. But SSC is also brittle nature like conventional concrete, which results in abrupt failure without giving any deformation (warning), which is undesirable for any structural member. Thus, self-compacting concrete (SCC) needs some of tensile reinforcement to enhance tensile strength and prevent the unsuitable abrupt failure. But fiber increased tensile strength of concrete more effectively than compressive strength. Hence, it is essential to add pozzolanic materials into fiber reinforced concrete to achieve high strength, durable and ductile concrete. This study is conducted to assess the performance of SCC with substitutions of marble waste (MW) and coconut fiber (CFs) into SCC. MW utilized as cementitious (pozzolanic) materials in percentage of 5.0 to 30% in increment of 5.0% by weight of binder and concrete is reinforced with CFs in proportion of 0.5 to 3.0% in increment of 0.5% by weight of binder. Rheological characteristics were measured through its filling and passing ability by using Slump flow, Slump T50, L-Box, and V-funnel tests while mechanical characteristics were measured through compressive strength, split tensile strength, flexure strength and bond strength (pull out) tests. Experimental investigation show that MW and CFs decrease the passing ability and filling ability of SCC. Additionally, Experimental investigation show that MW up to 20% and CFs addition 2.0% by weight of binder tend to increase the mechanical performance of SCC. Furthermore, statistical analysis (RSM) was used to optimize the combined dose of MW and CFs into SCC to obtain high strength self-compacting concrete.

Mechanical strengths, drying shrinkage and pore structure of cement mortars with hydroxyethyl methyl cellulose

This paper aims at investigating the long-term mechanical strengths and drying shrinkage, as well as pore structure of cement mortars with hydroxyethyl methyl cellulose (HEMC). The results show that the 3-d flexural strength and compressive strength of cement mortars tend to decrease with the HEMC content increasing. At 28 d to 360 d, the strengths keep decreasing with the HEMC content increasing at 0–1%, and then increase from the minimum value with the HEMC content increasing at 1–3%, still being much lower than those of the control (0% HEMC). Throughout the curing age, both the tensile bond strength and the drying shrinkage value gradually increase with the HEMC content, to be nearly twice at 3% HEMC than those of the control. HEMC significantly delays the 3-d hydration of cement pastes, but has negligible retardation effect on the hydration after 28 d, to bring the similar late hydration degree of cement pastes with HEMC or not. With the HEMC content increasing in the range of 0–1%, incorporating HEMC brings the sharp increase of macro pores, large capillary pores and porosity, and decreases the interconnected pores to bring many more closed pores. Further increasing the HEMC content to 3%, macro pores and porosity decrease, large capillary pores slightly increase and interconnected pores have a negligible change. Obviously, the understanding on the performance development of cement mortars with HEMC is conducive to the better application of HEMC in dry-mix mortars to meet different requirements.

Analysis of Changes in the Tensile Bond Strenght of Soft Relining Material with Acrylic Denture Material.

Abrasions and pressure ulcers on the oral mucosa are most often caused by excessive pressure or incorrect fitting of the denture. The use of soft relining materials can eliminate pain sensations and improve patient comfort. The main functional feature of soft elastomeric materials is the ability to discharge loads from the tissues of the mucosa. (1) Background: The aim of the work was a comparative laboratory study of ten materials used for the soft lining of acrylic dentures. (2) Methods: There were materials based on acrylates (Vertex Soft, Villacryl Soft, Flexacryl Soft) and silicones (Sofreliner Tough Medium, Sofreliner Tough Medium, Ufi Gel SC, GC Reline Soft, Elite Soft Relining, Molloplast). Laboratory tests include the analysis of the tensile bond strength between the relining material and the acrylic plate of the prosthesis. The tests were conducted taking into account 90-day term aging in the distilled water environment based on the methodology presented in the European Standard ISO 10139-2. (3) Results: After three months of observation, the highest strength of the joint was characterized by Flexacryl Soft acrylic, for which the average value was 2.5 MPa. The lowest average value of 0.89 MPa was recorded for the GC Reline Soft silicone material. Over time, an increase in the value of the strength of the combination of acrylic materials and a decrease in these values in the case of silicone materials was observed. (4) Conclusion: Each of the tested silicone materials showed all three types of damage, from adhesive to mixed to cohesive. All acrylic-based materials showed an adhesive type of failure. Time did not affect the type of destruction.

Soft Denture Liner Adhesion to Conventional and CAD/CAM Processed Poly(Methyl Methacrylate) Acrylic Denture Resins-An In-Vitro Study.

This study aimed to evaluate the airborne-particle abrasion surface treatment effects on the tensile bond strength (TBS) between resilient denture liner and CAD/CAM or conventional heat polymerized poly (methyl methacrylate) (PMMA) acrylic denture resins. A total of 48 dumbbell-shaped specimens (70 mm in total length, and 12 mm and 7 mm in diameter at the thickest and thinnest section, respectively) were prepared from CAD/CAM and conventional acrylic resins. Before relining with denture liner, 12 specimens from each material were surface-treated by 110 µm Al2O3 airborne-particle abrasion, and the remaining specimens served as control (no treatment). Following relining, all the specimens were aged by thermal cycling (1000 cycles, 5–55 °C). The TBS of denture liner to acrylic denture resins was tested in a universal testing apparatus at a 5 mm/min crosshead speed. The debonded surfaces were visually examined for the failure modes. ANOVA and multiple comparisons posthoc analysis tests were applied to determine the significant difference in TBS between the study groups (α = 0.05). A significant difference in TBS was observed between the control and surface treated groups (p < 0.001) for both acrylic resins materials. However, there was no statistically significant difference in bond strength between the acrylic resins materials (p = 0.739). Surface treatment with airborne-particle abrasion demonstrated increased TBS of the soft denture liners to acrylic resins. The TBS of conventional and CAD/CAM acrylic resins to soft denture liners were not considerably different.

Mechanical and microstructural properties of 3D printable concrete in the context of the twin-pipe pumping strategy

To tackle the conflicts between the pumping and deposition process in 3D concrete printing, a twin-pipe pumping (TPP) system with a helical static mixer can be used. In this way, a cement-based mixture (without accelerator) and a limestone powder-based mixture (with a high dosage of accelerator) are transported separately and mixed within the helical static mixer just before extrusion. However, the helical static mixer will introduce striation patterns in the 3D printed concrete due to flow division and the effect of such a heterogeneous phenomenon on the mechanical behavior has not been studied yet. In this paper, the mechanical (compressive, flexural, and tensile bond strength) and the microstructural behavior of 3D printed specimens made using the TPP system was explored. During the mechanical tests, the cracks initiated within the limestone powder striation. In addition, the difference in the mechanical strength for the specimens under difference loading directions was observed. Microstructural investigations based on mercury intrusion porosimetry revealed that the pore size distribution of 3D printed specimens (critical pore size of 210.0 nm and 197.5 nm for the bulk and interface region, respectively) was distinct from that of the mould cast specimens (critical pore size of 62.7 nm). Although the mould cast specimens had higher porosity (19.75%), the volume of macropores was found to be higher in the 3D printed specimens, which was more detrimental to the compressive strength. Further, porosity analysis of micrographs showed that the macropores in the 3D printed specimens were primarily presented in the limestone powder-based striations. In addition, a small quantity of ettringite was also observed in the bulk of the limestone powder-based striation, which may be caused by ion migration between the two regions after the inline mixing process by the static mixer.

Estimation of bond strengths and design parameters for precast concrete-UHPC shear key interface in box beam bridge

Adjacent precast prestressed concrete box beam bridge is often the choice for short-to-medium span bridges. However, it has been reported that box beam bridges experienced reoccurring longitudinal cracks at beam-shear key interfaces. The interface experiences a complex stress state represented by tensile/compressive stress perpendicular to the interface and longitudinal and vertical shear stress parallel to it. In this study, small-scaled specimens were cast together with the box beams and UHPC shear keys of a real bridge and were tested using four different test methods that try to replicate the actual stress conditions. The interface experienced satisfactory bond strength under different stress scenarios even at early age. The cohesion and friction coefficients were determined based on analysis of the experimental data and can be used to estimate the interfacial bond capacity at early age of UHPC. The interfacial bond capacity of a typical bridge was also determined and compared with the stress due to design truck load. The results indicate that the early age shrinkage and thermal load on the interface is more critical compared to the effects of the truck load. When subjected to the design truck load specified by current code, only 4.9% of the bond capacity was used, while the interfacial bond strength during the early age was exceeded. This indicates that the load is not the critical factor that causes bond failure at beam-shear key interface in box beam bridges. Furthermore, the cohesion value is sufficient to resist the applied load and the shear reinforcement can be optimized in the future application of UHPC in box beam bridges. Meanwhile, the early age tensile bond strength was exceeded and therefore the use of shear reinforcement to carry the early age tensile stress is necessary to prevent cracking.

Effectiveness of dentin pre-treatment on bond strength of two self-adhesive resin cements compared to an etch-and-rinse system: an in vitro study.

Statement of problemIt has been shown that selective etching improves the bond strength of some self-adhesive resin cements to enamel. The same has yet to be determined with dentin pre-treatment.PurposeTo evaluate the tensile bond strength of two self-adhesive resin cements after two dentin surface pre-treatments, and also to analyze the cement/dentin interface.Material and MethodsOne hundred and twelve human third molars were extracted. The teeth were distributed into seven groups (n = 16). Maxcem Elite Chroma (MAX) (Kerr, Scafati, Italy) and Relyx U200 (RLX) (3M ESPE, Neuss, Germany) were used without pre-treatment or with two dentin pre-treatments (polyacrylic acid or phosphoric acid). A conventional etch-and-rinse (EAR) luting cement, NX3 Nexus (NX3) (Kerr, Scafati, Italy), was used as an external control group. Before testing, all specimens were stored in distilled water for 24 hours. Three specimens from each group were prepared for scanning electron microscopy observation (SEM). A tensile bond strength test (TBS) was performed for the remaining samples. The data were statistically analyzed using the Kruskal–Wallis test and Pairwise comparisons using the Wilcoxon rank sum test.ResultsMAX without pre-treatment and with phosphoric acid etching attained statistically similar bond strengths to NX3 (P > 0.05). There was a statistical difference (P = 0.00488) between RLX without pre-treatment (5.62 MPa) and NX3 (10.88 MPa). Phosphoric acid pre-treatment increases the bond strength values of RLX to a strength that is comparable to NX3 (P > 0.05). The lowest tensile bond strength (TBS) was attained after the application of polyacrylic acid with MAX (1.98 MPa). No statistical differences were found between the RLX bond strength values after polyacrylic acid treatment and RLX without pre-treatment or NX3 (P > 0.05). SEM observations disclosed an enhanced potential of the self-adhesive cements to infiltrate into dentin tubules and form resin tags when applied after phosphoric acid pre-treatment. The failure mode was dominantly adhesive.ConclusionsOn dentin, the self-adhesive resin cement MAX might be an effective alternative to conventional resin cement. Etching the dentin with phosphoric acid does not have a negative effect on the bond strength of MAX to dentin. On the other hand, phosphoric acid improved the bond strength of RLX when compared to EAR cement.

Effect of crumb rubber powder on mechanical properties and pore structure of polyurethane-based polymer mortar for repair

In this study, the effect of crumb rubber powder (CRP) on the mechanical properties and internal pore structure of polyurethane-based polymer mortar (PUM) were investigated. According to the principle of volume fractions replacement of sand by 0 to 15% (5% interval), the CRP with a particle size of 0.25 mm was incorporated in the various mixture of polyurethane-based polymer mortar. For each PUM mixture were tested for compressive and flexural strengths, bond tensile strength. Mercury intrusion porosimetry (MIP) was used to analyze the distribution of pore size inside the material. The results show that the addition of 5% CRP was beneficial to improve the mechanical performances and the internal pore diameter distribution of PUM. No reduction in compressive and flexural strengths and the bond tensile strength was effectively increased by 7.9% and 17.3%, respectively. The total pore volume and porosity were reduced. Overall, the PUM contenting 5% CRP was recommended for repair.

Composite Cement Components Stabilize the Bond between a Lithium-Disilicate Glass-Ceramic and the Titanium Abutment.

To evaluate the effect of composite cement components and thermocycling on the bond strength of monolithic lithium-disilicate (LS2) glass-ceramic implant-supported restorations bonded to titanium (Ti) abutments. Eighty LS2 blocks were treated with five types of composite cement and primer, then divided accordingly into groups: M (Multilink hybrid abutment), G (G-CEM LinkAce), GP (G-CEM LinkAce with G-Multi PRIMER), P (Panavia F2.0), and U (RelyX U200). Half of the 16 specimens from each group were subjected to thermocycling (groups T-M, T-G, T-GP, T-P, and T-U). The tensile bond strength (TBS) of all specimens was measured using a pull-off test. The cross section of the LS2 block from which the Ti abutment was removed was examined for mode of failure. Two-way ANOVA and Tukey's HSD test (significance level = 0.05) were used to determine the effect of composite cement composition and thermocycling on TBS. There was no difference in TBS between the five groups before thermocycling (p = 0.16). However, groups M (p < 0.001) and G (p = 0.014) showed significantly lower TBS than the corresponding thermocycled groups. Groups T-GP, T-P, and T-U did not show significant changes in TBS after thermocycling (p > 0.05). All failures occurred at the interface between the composite cement and Ti abutment and not between the cement and the LS2 block. Thermocycling can reduce the bond strength between the composite cements and Ti abutment. The composite cements containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) or methacrylate phosphate ester monomers stabilize bonding.

Assessment Of Tensile Bond Strength Of Ceramic Restoration Material Comparing Two Immediate Dentin Sealing Protocols

ABSTRACT Aim: The aim of this study was to evaluate the effect of two immediate dentin sealing protocols including sealed dentin surface refreshment with air abrasion versus sealed dentin surface refreshment with pumice on tensile bond strength of ceramic restoration material. Materials and methods: Twenty extracted human molars were used. The prepared teeth were randomly divided into two groups according to the surface refreshment method into group (C): Air abrasion using Cojet and group (P) using pumice slurry. Twenty ceramic discs were sliced into standard thickness of 2mm ceramic slices. The teeth were immediately sealed using single bond universal adhesive it was then covered using a layer of provisional filling material directly after cutting. The provisional filling was then removed and dentin was cleaned using either airborne-particle abrasion (CoJet, 3M ESPE) (Group (C) or Pumice (group (P). The specimens in each group were then thermo-cycled and tensile bond strength test was done, using Universal Testing Machine. One-way ANOVA was used to study the effect of different tested variables and their interaction. Results: Samples done using air abrasion with Cojet, showed higher tensile bond strength than those using pumice. Conclusions: Immediate dentin sealing treatment would be recommended within high tensile stresses, when surface refreshment done by air abrasion to the tooth structure.

Hybrid geopolymer-cement coating mortar optimized based on metakaolin, fly ash, and granulated blast furnace slag

The use of wastes for new binders aims to reduce the environmental impact caused by the manufacture of Portland cement (PC) given the advance of urbanization. In this work, the main effects of the use of Geopolymer Cement (GC) in partial replacement to PC in mortars for coating were investigated. The GC was obtained from mixtures of industrial wastes, fly ash (FA), granulated blast furnace slag (GBFS), and metakaolin (MK), activated by a solution composed of alkaline sodium silicate (SS) and potassium hydroxide (KOH). The factors used for the experimental planning were the cement replacement content, T (10, 30, and 50%, by weight) and the aggregate-cement ratio, A/C (6.11, 6.90, and 7.69, by weight). Some properties were evaluated initially: consistency, compressive strength, durability (sulfate attack) and microstructural analysis (SEM, XRD, DSC, and TG). For optimized mixture and reference were tested: consistency, setting time, the heat of hydration, water retention, compressive strength, flexural tensile strength, tensile bond strength, dimensional variation, water absorption, voids content, elastic modulus, and thermal conductivity. The results are promising for the use of GC in mortars. The optimized mortar reached values of compressive strength and flexural tensile strength of 5.65 MPa and 1.73 MPa, respectively. The results showed the feasibility of using as eco-friendly mortar for internal and external coating, or as a mortar to repair degraded coatings. Hybrid mortars did not show good performance for attack by sulfates.

Long-term performance and hydration of cement mortars with hydroxyethyl methyl cellulose cured at 5℃ low temperature

As one of the special curing regimes, low temperature environment is considered to be crucial to the development of various properties of cementitious materials. This work focuses on the long-term performance and hydration of cement mortars with hydroxyethyl methyl cellulose (HEMC) cured at 5℃. The results show that the mid-late flexural and compressive strengths decrease with the HEMC content increasing, to get the lowest values at 1% HEMC. Afterwards, with the HEMC content increasing to 3%, the above strengths gradually increase, still being lower than those of the control. The tensile bond strength increases with the HEMC content increasing, to reach the maximum value at 0.3–0.5% HEMC, and then decreases with the HEMC content increasing to 3%, which is still much higher than that of the control. The drying shrinkage presents a significant increase with the HEMC content increasing. Moreover, HEMC significantly retards the early hydration of cement pastes. But the final hydration degree of cement pastes with HEMC tends to be close to that of the control. In addition, macro pores and the total porosity increase with the HEMC content increasing at 0–1%, and then decrease to some extent at 3% HEMC. Obviously, due to its better long-term properties at 5℃, the cement mortars with HEMC are still applicable at low temperatures.

Property comparison of steel slag cement mortar with hydroxyethyl methyl cellulose having different degrees of substitution and PAAm modification

The aim of this study is to explore the influence of HEMC with different total substitution degrees and polyacrylamide (PAAm) modification on the properties of steel slag cement mortar. The results show that HEMC increases the water retention rate, consistency, tensile bond strength, and flexibility of all types of steel slag cement mortars. The addition of HEMC, however, leads to a decrease in compressive strength and flexural strength. The total substitution degree or PAAm modification of HEMC has a minor effect on the water retention rate, compressive strength, flexibility, and pore size distribution of steel slag cement mortar. HEMC with a higher total substitution degree is more beneficial to the development of tensile bond strength except for SL1 cement mortar at an early age (3 days and 7 days), whereas PAAm weakens the positive effect of HEMC on the tensile bond strength. Mercury intrusion porosimeter (MIP) tests show that the addition of HEMC increases the porosity of steel slag cement mortar.

Improving bond strength and mass transport properties of spacer-concrete interface with textured spacers

Spacers are important devices used in all concrete structures to support reinforcing steel and achieve the required cover. However, spacers induce a weak, porous and microcracked interface that facilitates ingress of aggressive agents. This paper aims to address the problem by developing a method to produce cementitious spacers with a range of small-scale surface textures including grooves, squares, rectangles, hemispheres and pyramids. The textured spacers were cast in Portland cement mortar or concrete, cured up to 28 days, and tested for tensile bond strength, accessible porosity and mass transport properties. The properties were correlated to surface characteristics to establish the effects of texture on spacer-concrete interface. Results show that textured spacers promote mechanical interlocking with concrete, thereby increasing bond strength, resistance against microcracking and pressure-induced flow. The use of certain textures can compensate for the negative effects of spacers, achieving similar bond strength and permeability to monolithic concrete without the interface.

Effect of Remineralisation with Nano-hydroxyapatite (nHAp) and Non-collagenous Protein Analogues (PAA and STPP) on the Micro Tensile Bond Strength of the Resin Composites to Dentin – An In vitro Study

Background: Resin-dentin bonds are less durable than enamel as they rely on organic part for mineralisation. Bond denaturation mainly takes place because of hydrolysis of polymerized resin or degradation of water-rich, resin-sparse collagen by collagenolytic endogenous matrix metalloproteinase and cysteine cathepsins. Hence, this limited stability of dentin bonding tenaciously reduces the longevity of tooth-coloured restorations. One of the strategies adopted to encounter this shortcoming is to induce biomimetic remineralisation.&#x0D; Aim: To assess the microtensile bond strength of resin composites to dentin following remineralisation using an experimental paste containing nano-hydroxyapatite (nHAp) and biomimetic analogues, Poly Acrylic Acid (PAA) and Sodium Tri Polyphosphate (STPP).&#x0D; Methodology: Nine intact freshly extracted third molar were used for this study to evaluate the microtensile bond strength after treating with three different groups; Group I with paste containing nano hydroxyapatite nHAp Group II paste containing nHAp and non-collagenous protein analogues such as (Polyacrcrylic acid and Sodium tripolyphosphate) and the control groups containing adhesive and resin composite with no additional treatment. The samples were observed over a period of 24 hours and 1 week the inter group data analysis was done using ANOVA and paired sample t test and the intra-group data analysis over period of 24 hours the post HOC Bonferroni test was used for the statistical analysis.&#x0D; Results: After 24 hours the group with nHAp group showed highest value for microtensile bond strength among other groups, however after one week the group with nHAp +NCP analogues(PAA+STPP) showed highest value for microtensile bond.&#x0D; Conclusion: The treatment with the experimental paste [nHAp+NCP] analogues (PAA+STPP)] can bring about remineralisation to improve bonding to dentin.

Lapisan Plasma Spray Ni-Al dan Al-Si Pada Tabung Baja Tahan Karat Austenitik Dengan Jarak Semprot Terbatas (Atmospheric Plasma Spray Coating of Ni-Al and Al-Si on Austenitic Stainless-Steel Tube with Limited Short Spray Distance)

Atmospheric Plasma Spray (APS) coating is a widely used thermal spray coating process in industrial applications. High density and high bond strength coating are the main features of this process that is required in almost coating properties for specific applications. The geometrical condition of the workpiece substrate dictates the parameter needed to achieve a certain quality of the coating. Changes in the geometry require modification on the parameter of the process to maintain the quality of the coating. Aluminum Silicon and Nickel Aluminum coating were applied on Stainless Steel substrate casing. Due to the limitation of spray distance between nozzle gun and substrate surface of the casing, modified several parameters of the process were taken. Several parameters were investigated to find out the optimum result of coating and verified with tensile bond strength test, hardness test, and microscopic analysis examination. These activities that involved modification of parameters, mechanical testing, and visual inspection informed that power as a function of voltage and ampere, powder feed rate, the surface speed of substrate (the particular amount of workpiece rotation per minute), and traverse speed of gun, contribute to the result of the optimum coating.

COMPARATIVE STUDY OF THE TENSILE BOND STRENGTH OF RENDERING MORTARS IN CERAMIC AND CONCRETE STRUCTURAL BLOCKS

The tensile bond strength is one of the main properties of rendering mortars. It represents the adhesiveness ability between the mortar itself and the substrate. This property depends on several factors, such as the proportion and characteristics of the mortar materials and the substrate, along with the mode of application and climate conditions. The purpose of this paper was to analyze the tensile bond strength between three rendering mortar proportions in volume – 1: 1: 6, 1: 2: 9, and 1: 6 (with plasticizer additive) – each one applied on two substrates, ceramic structural blocks with roughcast and concrete structural blocks. The rendering mortars had their physical properties evaluated in fresh and hardened stages, as well as their compressive and tensile strengths in flexure. The tensile bond strength was determined by a pullout test on ceramic and concrete masonry walls exposed to external weather. The results showed that the 1: 1: 6 mixed mortar exhibited higher tensile bond strength in both substrates of ceramic blocks with roughcast and concrete blocks without preparation. Besides, among 1: 2: 9 and 1: 6 mortars there is no significant difference in tensile bond strength considering both substrates. Another conclusion was that the substrate type did not affect the final bond strength between the mortars.