Type Of Surface Treatment Research Articles

Effects of different etching methods and bonding procedures on shear bond strength of orthodontic metal brackets applied to different CAD/CAM ceramic materials.

To investigate the shear bond strength (SBS) of orthodontic metal brackets applied to different types of ceramic surfaces treated with different etching procedures and bonding agents. Monolithic CAD/CAM ceramic specimens (N = 120; n = 40 each group) of feldspathic ceramic Vita Mark II, resin nanoceramic Lava Ultimate, and hybrid ceramic Vita Enamic were fabricated (14 × 12 × 3 mm). Ceramic specimens were separated into four subgroups (n = 10) according to type of surface treatment and bonding onto the ceramic surface. Within each group, four subgroups were prepared by phosphoric acid, hydrofluoric acid, Transbond XT primer, and Clearfill Ceramic primer. Mandibular central incisor metal brackets were bonded with light-cure composite. The SBS data were analyzed using three-way analysis of variance (ANOVA) and Tukey HSD tests. The highest SBS was found in the Vita Enamic group, which is a hybrid ceramic, etched with hydrofluoric acid and applied Transbond XT Adhesive primer (7.28 ± 2.49 MPa). The lowest SBS was found in the Lava Ultimate group, which is a resin nano-ceramic etched with hydrofluoric acid and applied Clearfill ceramic primer (2.20 ± 1.21 MPa). CAD/CAM material types and bonding procedures affected bond strength ( P < .05), but the etching procedure did not ( P > .05). The use of Transbond XT as a primer bonding agent resulted in higher SBS.

Разработка компьютерных моделей баллистических тканей с поверхностной обработкой

Ballistic fabrics are widely used in protective armor structures. Minimizing the mass of armored structures, reducing the kinetic energy of the bullet transmitted to the object located behind the armored panel (for reducing the amount of deflection of the rear side of the panel) are actual tasks for today. A significant part of the energy of the bullet is dissipated due to the work of frictional forces when pulling yarns from the fabric. Ability to predict the work of ballistic fabric when pulling yarn from the fabric will allow designing high-performance armored structures. Therefore, low-parametric numerical models of pulling a yarn from aramid fabric P110 of plain weave, as well as for this fabric with different types of surface treatment (rosin, silicone grease) were developed using the LS-DYNA software package. Surface treatment of the fabric allows you to change the coefficient of friction between threads with minimal weight gain. In the model, the surface treatment was accounted for by changing one parameter of the coefficient of dry friction. Several methods of parallelizing the problem of pulling a yarn from a fabric are considered. Numerical experiments were conducted to study the scalability of problem. The calculated curves of the load from displacement when drawing a thread from a fabric with and without surface treatment were obtained. The calculated results are in the range of the scatter of the experimental data.

Bond Strength between Zirconia Y-TZP and Resin Cements: Evaluation of Surface Treatment, Cure Mode, and Failure Types

Purpose nbsp The aim of this study was to evaluate the effect of the type of curing and surface treatment with universal adhesive containing methacryloyloxydecyl dihydrogen phosphate MDP and sandblasting with aluminum oxide particles mu m on the bond strength between two resin cements RelyX Ultimate and U and yttria stabilized zirconia Y TZP Materials and methods nbsp Zirconia cylinders times times mm were divided into two groups according to the type of cement for dual and chemical curing Each group was divided into four subgroups n according to the surface treatment adhesive and sandblasting adhesive only sandblasting only and control no treatment After cementation specimens underwent shear bond strength testing in a universal testing machine A stereomicroscope was used to analyze the failure pattern Data were statistically analyzed considering p lt Results For both dual cure cements the highest values were found for the adhesive and sandblasting treatment group The results for dual curing were statistically different from the results for chemical curing Adhesive failure prevailed with both cements Conclusion The use of adhesive with MDP can be a favorable alternative to improve the bond strength between resin cements and zirconia Y TZP Sandblasting with aluminum oxide particles is not a key factor in improving bond strength

Effects of femtosecond laser and other surface treatments on the bond strength of metallic and ceramic orthodontic brackets to zirconia.

Femtosecond laser has been proposed as a method for conditioning zirconia surfaces to boost bond strength. However, metallic or ceramic bracket bonding to femtosecond laser-treated zirconia surfaces has not been tested. This study compared the effects of four conditioning techniques, including femtosecond laser irradiation, on shear bond strength (SBS) of metallic and ceramic brackets to zirconia.Three hundred zirconia plates were divided into five groups: 1) control (C); 2) sandblasting (APA); 3) silica coating and silane (SC); 4) femtosecond laser (FS); 5) sandblasting followed by femtosecond laser (APA+SC). A thermal imaging camera measured temperature changes in the zirconia during irradiation. Each group was divided into 2 subgroups (metallic vs ceramic brackets). SBS was evaluated using a universal testing machine. The adhesive remnant index (ARI) was registered and surfaces were observed under SEM. Surface treatment and bracket type significantly affected the bracket-zirconia bond strength. SBS was significantly higher (p<0.001) for ceramic brackets in all groups (APA+FS > APA > FS > SC > control) than metallic brackets (APA+FS > FS > SC > APA > control). For metallic brackets, groups SC (5.99 ± 1.86 MPa), FS (6.72 ± 2.30 MPa) and APA+FS (7.22 ± 2.73 MPa) reported significantly higher bond strengths than other groups (p < 0.05). For ceramic brackets, the highest bond strength values were obtained in groups APA (25.01 ± 4.45 MPa), FS (23.18 ± 6.51 MPa) and APA+FS (29.22 ± 8.20 MPa).Femtosecond laser enhances bond strength of ceramic and metallic brackets to zirconia. Ceramic brackets provide significantly stronger adhesion than metallic brackets regardless of the surface treatment method.

Evaluation of surface treatments of monolithic zirconia in different sintering stages

PurposeThis study evaluated the effect of surface treatment of zirconia in pre-sintered and post-sintered stages on its surface roughness, phase transformation, and biaxial flexural strength (BFS). MethodsZirconia ceramic discs (n=40) having a final dimensions of 12mm diameter and 1.2mm thickness were milled then divided into three main groups according to the type of surface treatment performed (Group 1 (n=16); air-abrasion using Al2O3 particles, Group 2 (n=16); silica coating using Rocatec soft, and Group 3 (n=8); a control group receiving no surface treatment). Groups 1 and 2 were divided into two subgroups each according to the stage in which the surface treatment was performed (Subgroup A; surface treatment performed in the pre-sintered stage and subgroup B; surface treatment performed in the post-sintered stage). Surface roughness, phase transformation, and biaxial flexural strength (BFS) were later assessed. Data was then analyzed using two-way ANOVA and Tukey post-hoc tests at a significance level of p≤0.05. ResultsSubgroups treated in the pre-sintered stage showed higher mean Ra in μm (1.81±0.36) when compared to the subgroups treated in the post-sintered (0.68±0.07) stage and the control group (0.51±0.10) (p≤0.05). The pre-sintered treated group and the control showed no monoclinic phase while the post-sintered group showed significantly higher portions of monoclinic phase. Regarding BFS the post-sintered treated group had statistically significant higher values in MPa (1228±81) when compared to the pre-sintered treated group (940±101) and the control (1019±82) (p≤0.05). ConclusionsAir abrasion in the pre-sintered stage might be a promising surface treatment method to produce promising surface roughness values of zirconia without subjecting it to early degradation.

Glass Masonry - Experimental Verification of Bed Joint under Shear

Glass is considered as a traditional material for building industry but was mostly used for glazing of the windows. At present, glass is an integral part of contemporary architecture where glass structural elements such as beams, stairs, railing ribs or columns became popular in the last two decades. However, using glass as structural material started at the beginning of 20th century, when masonry from hollow glass blocks were used. Using solid glass brick is very rare and only a few structures with solid glass bricks walls have been built in the last years. Pillars and walls made from solid glass bricks are mainly loaded by compression and/or bending from the eccentricity of vertical load or wind load. Due to high compressive strength of glass, the limiting factor of the glass masonry is the joint between the glass bricks as the smooth surface requires another type of mortar / glue compared to traditional masonry. Shear resistance and failure modes of brick bed joint was determined during series of tests using various mortars, two types of surface treatment and different thickness of the mortar joint. Shear tests were completed by small scale tests for mortar – determination of flexural and compressive strength of hardened mortar.

In Vitro Study Compared The Shear Bond Strength of HEMA-free and HEMA-containing Bonding Agents To Different Dentin Surface Treatments

This research was designed to investigate the effect of two dentin surface treatments on the shear bond strength of HEMA-free and HEMA containing bonding agent. A total of 90 freshly extracted, sound human molars, free from caries, extracted for pathological reasons was used in this study. The molars were randomly divided into two main equal groups (45 teeth each) according to the type of adhesive system; Group (A1) used HEMA-free adhesive (G-bond). Group (A2) used HEMA containing adhesive (One-up Bond F Plus). Each group was further subdivided into 3 equal subgroups(15teeth each) according to the type of dentin surface treatments applied as follows: Subgroup (I) used the bonding agent only without surface treatment as a control [AB], Subgroup (II) used 10% Sodium hypochlorite followed by the bonding agent [AB1], Subgroup (III) used 10% Sodium hypochlorite then 10% Sodium ascorbate followed by the bonding agent [AB2]. Each subgroup was further divided into three groups of (5 teeth each) according to the storage times; 24 hours, three months, and six months. A Flat dentin surface was prepared, different surface treatments and adhesive systems were applied then Composite was bonded to the treated surfaces according to the manufacturer’s instructions and the shear bond strength testing was done using universal testing machine. The recorded values were tabulated and statistically analysed. The result of this study revealed that; the highest mean shear bond strength (18.39 +/- 2 MPa) wasrecorded for those dentin specimens bonded to composite resin with HEMA-containing adhesive (One-up Bond F Plus) without surface treatment after 1 day storage time. While the lowest mean shear bond strength (10.7 +/- 1.6 MPa) was recorded for those dentin specimens bonded to composite resin with HEMA-free adhesive (G-bond) with sodium hypochlorite only after 6 months storage time. The results of this study revealed that 1- Sodium hypochlorite only has a significant adverse effect on the shear bond strength of both adhesives. 2- sodium hypochlorite followed by sodium ascorbate can render the adverse effect of sodium hypochlorite only on the shear bond strength of both adhesives.3- HEMA-containing adhesive (One-up Bond F Plus) without surface treatment showed better shear bond strength than HEMA-free adhesive (G-bond). 4-Storage in water for long periods has a highly significant adverse effect on the bondstrength especially of HEMA-containing adhesive.

Effect of the Type of Surface Treatment and Cement on the Chloride Induced Corrosion of Galvanized Reinforcements

The effect of a new passivation treatment, obtained by immersion of the galvanized reinforcements in a trivalent chromium salts based solution, on the chlorides induced corrosion has been investigated. To investigate also the effect of cement alkalinity on corrosion behaviour of reinforcements, concretes manufactured with three different European cements were compared. The obtained results show that the alternative treatment based on hexavalent chromium-free baths forms effective protection layers on the galvanized rebar surfaces. The higher corrosion rates of zinc coating in concrete manufactured with Portland cement compared to those recorded for bars in concrete manufactured with pozzolanic cement depends strongly on the higher chloride content at the steel concrete interface.

In Vitro Effect of Bleaching With 810 nm and 980 nm Diode Laser on Microhardness of Self-cure and Light-Cure Glass Ionomer Cements.

Introduction: This study sought to assess the effect of bleaching combined with irradiation of 810 nm and 980 nm diode laser on microhardness of 2 commonly used self-cure and light-cure glass ionomer cements (GICs) in comparison with conventional bleaching (without laser). Methods: In this in vitro, experimental study, 60 samples were fabricated of A2 shade of Fuji IX and Fuji II LC GICs (n=30) and each group was divided into 3 subgroups (n=10). The first subgroups were subjected to bleaching with Opalescence Xtra Boost plus 980 nm diode laser irradiation. The second subgroups were subjected to bleaching with Opalescence Boost plus 810 nm diode laser irradiation and the third subgroups were subjected to bleaching with Opalescence Xtra Boost without laser. Microhardness was measured at baseline and after the intervention using Vickers hardness tester. The data were analyzed using two-way analysis of variance (ANOVA) (P<0.05). Results: Microhardness decreased in all subgroups after the intervention (P<0.001) irrespective of the type of GIC (P=0.201) or surface treatment (P=0.570). The baseline microhardness of the three subgroups within each group of GIC was not significantly different (P=0.456), but the baseline microhardness of conventional GIC was significantly higher than that of resin modified GIC (P=0.004). Conclusion: Bleaching with/without laser irradiation decreases the microhardness of GICs. The baseline microhardness of conventional GIC is higher than that of resin modified GIC.

Fatigue behaviour improvement on notched specimens of two different steels through deep rolling, a surface cold treatment

Deep rolling is a type of surface treatment which allows increasing the lifetime under cyclic loads through compressive residual stress induced in the outer layers, improving this way the fatigue strength of the treated components. It is used in several sectors, such asaeronautic industry, wind turbines, as well as in vehicle components, among others. Deep rolling process enables to reduce the notch effect in those zones where fatigue damage could take place.Fatigue behaviour improvement is achieved through the enhancement of the surface finish, surface hardening and, mainly, due to the external layer of compressive residual stresses originated in the deep rolling process. In this way, fatigue crack initiation is retarded and the crack propagation rate is reduced.The increase of the endurance limit in two different D38MnV5S steels used in the manufacture of forged crankshafts was studied in this work. Notched specimens were employed in this study and the behaviour of those materials under cyclic loads before and after a deep rolling process was analysed and compared with the results obtained using smooth specimens. Furthermore, residual stress profiles were evaluated for different deep rolling process parameters by means of X-ray diffraction.

Surface Treatments for Controlling Solid Electrolyte Interphase Formation on Sn/Graphene Composite Anodes for High-Performance Li-Ion Batteries

Sn is a candidate anode material for high energy density Li-ion batteries, owing to its high specific capacity, low cost, and high electronic conductivity, but its practical applications are hindered by mechanical degradation induced by the large volume change during cycling. Graphene can be used as a buffer material for Sn volume expansion while also improving mechanical strength and electronic conductivity of the composite structure. We report here the synthesis of a composite of Sn nanoparticles and graphene through surface functionalization of graphene using diazonium grafting and subsequent Sn nanoparticle deposition. We further applied two types of surface treatments on the anode surface to improve the nucleation of the solid electrolyte interphase, which is formed due to the reduction of the electrolyte solution. These treatments include refunctionalizing the anode surface with graphene oxide sheets or sulfophenyl groups, which provide ample sites on the anode surface for the nucleation of the soli...

Shear bond strength of different surface treatments in bulk fill, microhybrid, and nanoparticle repair resins.

ObjectivesThe purpose of this study was to evaluate the influence of surface treatment and different types of composite resin on the microshear bond strength of repairs.Materials and methodsSeventy-two specimens (n=72) were prepared using a nanoparticle resin and stored in artificial saliva at 37 ± 1°C for 24 h. After this period, the specimens (n=24) were restored with microhybrid resin P60 (3M ESPE), nanoparticle resin Filtek Z350 (3M ESPE), and Bulk Fill Surefil SDR Flow (Dentsply) composite resins. Previously, the surfaces of the samples were treated, forming the following subgroups (n=12): (A) conditioned with 37% phosphoric acid for 30 s, and (B) abrasioned with a diamond tip for 3 s and conditioned with 37% phosphoric acid. In all groups, before insertion of the composite resin, the adhesive system Adper Single Bond 2 was actively applied and photopolymerized for 20 s.ResultsThe microshear test was executed to assess bond strength. Kruskal–Wallis (p<0.05) and Mann–Whitney statistical tests showed significant statistical difference considering that the bulk-fill resin turned out to have a lower bond strength than the conventional nanoparticle and microhybrid composites. With regard to the technique, the roughening with diamond bur followed by the application of phosphoric acid exhibited values higher than the exclusive use of acid.ConclusionThe microshear bond strength of the composite resin repairs varies in accordance with the type of composite resin utilized, and roughening the surface increased the bond strength of these materials.

Characterization of a Laser Surface-Treated Martensitic Stainless Steel.

Laser surface treatment was carried out on AISI 416 machinable martensitic stainless steel containing 0.225 wt.% sulfur. Nd:YAG laser with a 2.2-KW continuous wave was used. The aim was to compare the physical and chemical properties achieved by this type of selective surface treatment with those achieved by the conventional treatment. Laser power of different values (700 and 1000 W) with four corresponding different laser scanning speeds (0.5, 1, 2, and 3 m·min−1) was adopted to reach the optimum conditions for impact toughness, wear, and corrosion resistance for laser heat treated (LHT) samples. The 0 °C impact energy of LHT samples indicated higher values compared to the conventionally heat treated (CHT) samples. This was accompanied by the formation of a hard surface layer and a soft interior base metal. Microhardness was studied to determine the variation of hardness values with respect to the depth under the treated surface. The wear resistance at the surface was enhanced considerably. Microstructure examination was characterized using optical and scanning electron microscopes. The corrosion behavior of the LHT samples was also studied and its correlation with the microstructures was determined. The corrosion data was obtained in 3.5% NaCl solution at room temperature by means of a potentiodynamic polarization technique.

Laser surface structuring of Ti6Al4V substrates for adhesion enhancement in Ti6Al4V-PEEK joints

PEEK is a promising polymer possessing high mechanical strength and biocompatibility and therefore it can be associated to titanium for biomedical applications. This study aimed at producing Ti6Al4V-PEEK joints with enhanced adhesion through laser-structuring Ti6Al4V treatments. Ti6Al4V cylindrical substrates were prepared by two types of surface treatments: alumina blasting and laser structuring. The holes number and size in laser-structured surfaces was varied. PEEK was then hot pressed against the metallic substrate to completely filling the surface cavities. The adhesion of the PEEK/Ti6Al4V joint was assessed by a shear bond strength test. Fracture surfaces and interfaces were investigated by SEM/EDS. Significant differences were found in the shear bond strength between alumina blasted and laser-structured samples. Bond strength improvement (exceeding 300%) was registered for the laser-structured specimens relative to grit-blasted ones. The laser-structuring technique showed to be very promising in the production of specifically designed surfaces for high strength and mechanically stable Ti6Al4V/PEEK joints.

Comparison of Shear Bond Strength of Silorane and Methacrylate-Based Composites to IPS Empress 2 Ceramic with Various Surface Treatments

Objectives Treatment of chipped or fractured porcelain with composite resin is considered as an economic treatment for minor fractures in ceramics. The aim of this study was to evaluate the effect of different ceramic surface treatments on bond strength of methacrylate-based and silorane-based composite resin to IPS Empress 2.Methods Sixty IPS Empress 2 ceramic discs were fabricated and after etching with 9.6% hydrofluoric acid, they were divided into six groups:(1) P90 primer and bonding agent + Filtek P90 composite resin; (2) Single Bond + Filtek Z250 composite resin; (3) similar to the first group+ silane pretreatment; (4) similar to the second group + silane pretreatment; (5) silane pretreatment + Filtek P90 composite resin; (6) silane pretreatment + Filtek Z250 composite resin. Each specimen was subjected to shear load until fracture occurred. Statistical analysis was performed using one-way ANOVA, Tukey’s test and t-test.Results Regardless of the type of surface treatment, Z250 composite demonstrated significantly higher shear bond strength than P90 composite (P < 0.05). Group 4 showed the highest shear bond strength values with statistically significant difference with other groups while the fifth group showed the least values (P < 0.05).Conclusion Silane coating along with the application of adhesive system and etching in methacrylate-based composite was the most efficient surface treatment in terms of bond strength.

INVESTIGATION THE EFFECT OF RELATION BETWEEN CEMENT TYPE AND SURFACE TREATMENTS OF DIFFERENT CERAMIC TYPES ON THEIR SHEAR BOND STRENGTH WITH TOOTH STRUCTURE

Statement of problem: The clinical success of the ceramic restoration system that is strongly bonded to the tooth structure in order to prevent microleakage, marginal fracture, discoloration, and secondary caries. Which do types of cements and surface treatment considerably influence. Purpose: This study investigated the shear bond strength between three all ceramic systems (CAD-CAM CEREC type, The VM7( VITADURVEST) powder, and IPS Empress II) treated by air abrasion and hydrofluoric acid, then cemented to tooth structure by two types of adhesive resin cements.Material and methods: Ninety freshly extracted human lower third molar teeth were used. Each tooth was free of caries or restorations. Teeth were embedded into autopolymerizing resin limited to their cervical line using dental surveyor. The occlusal third of the molars was grounded using diamond stones under water coolant to make dentin discs with smooth and flat surface. Ceramic discs with 5mm diameter and 3mm thickness of three types of all ceramics and two types of chemically cured resin cements were used.All specimens were randomly divided into three groups of 30 teeth eachaccording to the ceramic used. Each group are divided into three subgroup(n=10). The bonding surfaces of each ceramic discs of each subgroup are treated with one of the following: 9% hydrofluoric acid, Airborne particle abrasion with 50 μm grain sized aluminum oxide particles and Air abraded with 50 μm grain sized aluminum oxide particles and etched in 9% hydrofluoric acid .The ceramic disks were bonded to the flattened molars using one of the two types of the resin cement used in this study. All samples were mounted on a computer controlled materials testing machine with a load cell of 5KN and their data were recorded using computer software. Results: The results of the present study showed the following mean loads at fracture: the Cerec type (7.56+1.96 N), VM7 (6.21+0.99 N) and Empress II (6.96+1.72 N) .ANOVA and Tukey’s post-hoc test showed that the differences between these all ceramics types were statistically nonsignificant(p>0.05). However the CAD-CAM Cerec blocs gave the highest mean of shear bond strength .on the other hand, Statically analysis of the results showed that the differences between the three types of surface treatment were statistically significant (p<0.05). Hydrofluoric acid etching produced the highest mean shear bond strength. Panavia dental adhesive is better than Dyract cem plus as it produced higher mean shear bond strength values in all cases of this study. Conclusions: The three types of All ceramic used in this study have no clear effect in the Shear bond strength of ceramic to tooth structure, Hydrofluoric acid etching produced the higher mean shear bond strength than air abrasion(AA) with aluminum oxides, and according to this study Panavia dental adhesive is better than Dyract cem plus in Shearbond strength.

Effect of Surface Conditioning with Airborne-Particle Abrasion on Certain Properties of Nano-Ceramic Material

Purpose: This study was conducted to evaluate the influence of air born-particle abrasion using three sizes of AL2O3; (50 μm, 110 μm, 150μm) on translucency and flexure strength of resin nano-ceramic (Lava Ultimate) material. Materials andMethods Forty samples were divided into 4 groups (n=10) according to the type of surface treatment conducted: Group (1): Lava Ultimate samples with no surface treatment (control group), Group (2): Lava Ultimate samples air- abraded withAL2O3 particle size 50μm, Group (3): Lava Ultimate samples air- abraded with AL2O3 particle size 110μm and Group (4): Lava Ultimate samples air-abraded with AL2O3 particle size 150μm, Translucency was determined using a portable reflective spectrophotometer and biaxial flexure strength test with a ball on ring was conducted.Data were statistically analyzed. Results: Samples treated with 110 um particle size (group 3), recorded the highest mean translucency value, meanwhile the lowest mean value was recorded for 150 um particle size treated samples (group 4). Regarding biaxial flexural strength 150 um particle size treated samples (group 4), recorded the highest mean value, meanwhile the lowest mean value was recorded the control group. Conclusions: Air- abrasion can be done with different particle size without affecting translucency and biaxial flexural strength of Lava Ultimate.

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

BackgroundFor success of any indirect metal restoration, a strong bond between cement and the intaglio surface of metal is imperative. The aim of this study is to evaluate and compare the effect of different surface treatment on the tensile and shear bond strength of different cements with nickel–chromium alloy.Material and Methods120 premolars were sectioned horizontally parallel to the occlusal surface to expose the dentin. Wax patterns were fabricated for individual tooth followed by casting them in nickel chromium alloy. 60 samples were tested for tensile bond strength, and the remaining 60 for shear bond strength. The samples were divided into three groups (of 20 samples each) as per the following surface treatment: oxidation only, oxidation and sandblasting, or oxidation, sandblasting followed by application of alloy primer. Each group was subdivided into 2 subgroups of 10 samples each, according to the bonding cement i.e RM-GIC and resin cement. Samples were subjected to thermocycling procedure followed by evaluation of bond strength.ResultsTwo-way analyses of variance (ANOVA) was performed to compare the means of tensile and shear bond strength across type of surface treatment and cement, followed by post hoc parametric analysis. For all tests ‘p’ value of less than 0.05 was considered statistically significant.ConclusionsThe surface treatment of oxidation and sandblasting followed by application of alloy primer offered the maximum tensile and shear bond strength for both RM GIC and resin cement. Resin cement exhibited greater tensile and shear bond strength than RM-GIC for all the three surface treatment methods. Key words:Resin cement, resin modified glass ionomer cement, oxidation, sandblasting, alloy primer, tensile bond strength, shear bond strength, universal testing machine.

EFFECT OF DIFFERENT SURFACE TREATMENTS AND RESIN TYPES ON BONDING TO TRANSLUCENT ZIRCONIA

Purpose: This in vitro study measured the adhesive properties of 10-MDP and MPE containing resin cements, using two types of zirconia surface treatments; selective infiltration etching(SIE) and airborne particle abrasion (APA) to translucent zirconia (3M, ESPE) .Statement of Problem: Due to translucent zirconia modified composition (alumina content reduced to tenth of its weight) bonding strength to different resin cements after different surface treatments should be investigated adequately . Materials and Methods:Sixty sintered Lava plus high translucency disks(3M,ESPE)were randomly divided into three study groups according to their surface treatment: (a) polished surface (control group); (b) air borne particle abraded (grit blasted) with 50 µm aluminum trioxide (APA); and (c) selective infiltration etching (SIE). Zirconia disks (15x2mm) were then bonded to 60 composite resin disks (8x4mm) using two different resin composite cements (Clearfil SA and Rely X). Resin-zirconia adhesion strength was evaluated using the microshear bond strength test (MSBS) after 24 hour of storage in deionized water at 37˚C. One way ANOVA and Scheffe s post-hoc tests were used to analyze the data (p<0.001). Then fractured samples were studied under SEM and classified according to failure pattern.Results: Different types of resin cement and surface treatment significantly influenced the MSBS (P<0.001). The highest mean MSBS values were recorded with MDP containing resin cement (Clearfil SA) in both SIE (26.18 ±1.12 MPa) and APA (21.67±1.34) groups. Bond strength values were reduced significantly in control group when using the two types of cements. Regarding failure pattern, MDP groups showed cohesive and MPE and control groups showed adhesive type.Conclusion: SIE and APA in combination with 10-MDP containing resin cement established a strong durable bond to zirconia substrates than MPE groups. SIE and APA showed significant higher bond strength values than control groups.

Influence of nano-structured alumina coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements.

PURPOSEThe purpose of this study was to evaluate the effect of nano-structured alumina surface coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements.MATERIALS AND METHODSA total of 90 disk-shaped zirconia specimens (HASS CO., Gangneung, Korea) were divided into three groups by surface treatment method: (1) airborne particle abrasion, (2) tribochemicalsilica coating, and (3) nano-structured alumina coating. Each group was categorized into three subgroups of ten specimens and bonded with three different types of dual-cured resin cements. After thermocycling, shear bond strength was measured and failure modes were observed through FE-SEM. Two-way ANOVA and the Tukey's HSD test were performed to determine the effects of surface treatment method and type of cement on bond strength (P<.05). To confirm the correlation of surface treatment and failure mode, the Chi-square test was used.RESULTSGroups treated with the nanostructured alumina coating showed significantly higher shear bond strength compared to other groups treated with airborne particle abrasion or tribochemical silica coating. Clearfil SA Luting showed a significantly higher shear bond strength compared to RelyX ARC and RelyX Unicem. The cohesive failure mode was observed to be dominant in the groups treated with nano-structured alumina coating, while the adhesive failure mode was prevalent in the groups treated with either airborne particle abrasion or tribochemical silica coating.CONCLUSIONNano-structured alumina coating is an effective zirconia surface treatment method for enhancing the bond strength between Y-TZP ceramic and various dual-cured resin cements.