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Purpose: To evaluate the effect of two surface conditioning methods, namely conventional hydrofluoric acid vs self-etching primer, and the application of adhesive on the bond strength of composite cement to CAD/CAM glass-ceramics. Materials and Methods: Blocks (N = 96) (12 x 10 x 2.5 mm) were manufactured, 24 for each tested ceramic type: lithium silicate ceramic (LS), polymer-infiltrated ceramic (PIC), leucite-reinforced feldspathic ceramic (FD), and lithiumdisilicate glass-ceramic (LD). For bond strength testing, 64 blocks were randomly divided into 16 groups (4 blocks per group) according to the following factors: ceramic: 4 levels; etching: 2 levels (HFS: hydrofluoric acid + silane or Monobond Etch & Prime [MEP]); and adhesive application: 2 levels, with (signified as A) and without. Then for each group, 15 composite cement cylinders (AllCem Dual, FGM) were built up. All specimens were subjected to thermocycling (10,000 cycles) and to shear bonding strength testing (SBS) (100 kgf, 0.5 mm/min). Mean shear stresses (MPa) were statistically analyzed by three-way ANOVA, Tukey's test, and Weibull analysis. Results: The mean bond strength of group PIC-HFS-A (28.45 ± 7.6 MPa) was significantly higher than that of groups LS-HFS-A (12.11 ± 2.7 MPa) and FDHFSA (20.86 ± 2.0 MPa). Group PIC-HFS bond strength (25.02 ± 6.5 MPa) was significantly higher only when compared to group LS-HFS (15.82 ± 4.4 MPa). The LS group presented lower SBS compared to all other groups. No significant differences were found between HFS and MEP surface treatments. Conclusion: Surface treatment with MEP promotes adhesion similar to that of HFS. Additional application of adhesive after the surface treatments did not improve the bond strength. [ABSTRACT FROM AUTHOR]

This study evaluated the mechanical behavior and risk of failure of three CAD-CAM crowns repaired with different resin composites through a three-dimensional (3D) finite element analysis. Three-dimensional models of different cusp-repaired (conventional nanohybrid, bulk-fill, and flowable resin composites) crowns made of zirconia, lithium disilicate, and CAD-CAM resin composite were designed, fixed at the cervical level, and loaded in 100 N at the working cusps, including the repaired one. The models were analyzed to determine the Maximum Principal and Maximum Shear stresses (MPa). Complementary, an in vitro shear bond strength test (n = 10) was performed to calculate the risk of failure for each experimental group. The stress distribution among the models was similar when considering the same restorative material. The crown material affected the stress concentration, which was higher for the ceramic models (±9 MPa for shear stress; ±3 MPa for tensile stress) than for the CAD-CAM composite (±7 MPa for shear stress; ±2 MPa for tensile stress). The shear bond strength was higher for the repaired CAD-CAM resin composite (±17 MPa) when compared to the ceramics (below 12 MPa for all groups), while the repair materials showed similar behavior for each substrate. The stress distribution is more homogenous for repaired resin composite crowns, and a flowable direct resin composite seems suitable to repair ceramic crowns with less risk of failure. [ABSTRACT FROM AUTHOR]

Introduction -- Indirect restorations are frequently luted to the remaining tooth structure with new age self-adhesive resin cements. Use of these advanced single step cements reduce chair side time for the clinician. In clinical practice it is not possible to achieve complete isolation in the oral cavity. Contamination during bonding procedures is inevitable, however shorter the time taken to perform the bonding procedure more effective the moisture control by conventional means. This contamination may alter the binding capacity of the cement to the dentine and thus affect the retention of the prosthesis. Aim -- To compare and evaluate the Shear Bond Strength of Two Self adhesive Resin Cements and Dentin with and without salivary fluid contamination. The null hypothesis states that there is no difference exists in the SBS after salivary contamination at the dentine interface. Materials and Method -- 40 freshly extracted premolar teeth were grounded occlusally and embedded in acrylic blocks. The 40 blocks were randomized into 4 groups. Each group was bonded with either resin cement before or after salivary contamination. All samples were tested using the Universal Testing Machine at a cross head speed of 0.5mm/min. The force of dislodging was noted. The data was then subjected to paired and unpaired t test. Results -- On analysis no statistically difference in SBS was noted between A1,B1 and A2,B2. On comparing the groups A1 and A2(after salivary contamination) and B1 and B2(after salivary contamination) p<0.05 was noted which was of statistical significance. Conclusion -Salivary Contamination reduced the SBS between the resin cements and dentin. The individual resin cements showed no statistical difference in shear bond strength. [ABSTRACT FROM AUTHOR]

AIM: To evaluate the shear strength of Orthocem and BracePaste polymerizable cement light‑cured with light‑emitting diode (LED) units with different wavelengths (Bluephase N) with their high power, low power, and soft start programs in the bonding of metal brackets. MATERIALS AND METHODS: In vitro experimental research was performed. Mini Roth 0.022 metal brackets (Roth Orthometric brackets) were used. The adhesives were placed on the metal brackets with Orthocem and BracePaste resin cement. To compare the average strengths, the analysis of variance (ANOVA) test was used (P < 0.05). RESULTS: The average shear strength was better with Bracepaste polymerizable cement compared to Orthocem cement in all its high power, low power, and soft star programs; the highest was Bracepaste with soft start of 26.52 MPa, and the lowest was Orthocem with soft start of 13.92 MPa. When evaluating the differences, it was found that these were statistically significant in all groups (P < 0.05). CONCLUSIONS: Differences were found in the shear strength of light‑curing Orthocem and Bracepaste light‑curing cement cured with LED units with different wavelengths in bonding metal brackets to the tooth in vitro. [ABSTRACT FROM AUTHOR]

Aims: This study aims to evaluate the shear bond strength of three types of dual-cure self-adhesive resin cement (SARCs) bonded to three different substrates with detection types of failure, EDX analysis for substrates, control substrate, and after three resin cement applications. Materials and methods: Thirty specimens from enamel and the same number from dentin and zirconia are prepared. Zirconia discs prepared by CAD-CAM system. Dental specimens prepared from intact surface 3rd molar for enamel and premolar for dentin. After teeth sectioning, all specimens are embedded in auto-cure acrylic resin in a plastic tube. All specimens were polished with sandpaper and zirconia sandblasting, rubber mold was fixed on the surface of the specimen. Three types of dual-cures (SARCs) were applied on the surface of the specimens and after curing the specimens were kept in distilled water at 37 ºC inside the incubator for 24 hours. Then specimens subjected to shear bond strength on a universal test machine after the failure occurs specimens examined under a stereomicroscope to detect the mode of failure. Three control specimens enamel, dentin, and zirconia without any treatment, and nine were from failure specimens send to EDX analysis. Results: The results of this study analyzed with SPSS 25 edition, results showed no significant difference in shear bond strength (SBS) between the three (SARCs) bonds to enamel substrate, while in dentin and zirconia, there was a significant difference in SBS between self-adhesive resin cement. Failure mode detected under the stereomicroscope examination shows no significant difference between the three substrates in failure mode when the bond to BisCem® and TheraCem®Ca, but RelyX™U200 showed a significant difference. EDX analysis shows the presence of Calcium, Phosphorus ions on the zirconia surface when TheraCem®Ca was applied while not present when using the other two types of cement. The amount of calcium and phosphorus ions different from one specimen to another related to the type of substrate and the cement when compare with the control group. Conclusion: TheraCem ®Ca showed improvement in SBS to zirconia due to its composition such as acidic monomer MDP and calcium and phosphorus ions. BisCem and RelyXU200 show better performance with tooth structure and comparable results with zirconia.

Aim: Clinicians and researchers have always made every effort to achieve proper bonding between the surface of the tooth and the rebonded orthodontic brackets in order to prevent the re-fracture failure of orthodontic pressures throughout treatment. The aim of this study was to determine the bond strength of rebonded brackets by four adhesive removal methods.Materials and methods: Seventy-five orthodontic brackets were bonded to the extracted first premolar teeth and then debonded. Fifteen of these teeth were rebonded to new brackets after adhesive removal and were named as the control group. Sixty debonded brackets were divided into four groups by means of resin-removal: laser, burr, sandblast, and direct flame. These recycled brackets were re-bonded to the teeth with the same basic bonding methods. The shear bond strength (SBS) was measured at the speed of 0.5 mm/min and the data were analyzed using ANOVA and post hoc tests (α=0.05).Results: SBS was significantly different in all four groups compared to the control group (p

In recent years, offshore wind power has been developing rapidly, and single piles are among the commonly used foundations for wind turbines. Presently, experimental studies of the grouted connections of pile foundations are limited to the study of scaler models. Numerical simulations are more suitable for the mechanical analysis of the full-size structure instead of experimental ones. In numerical simulations, the linear elasticity model is widely adopted, but the plastic damage is studied scarcely. So, shear bond parameter research concerning grouted joints needs to be supplemented. In this paper, a bilinear random-motion reinforcement model based on the classical metal plasticity theory is adopted for steel, and the model for the grouting material is based on the Sidiroff energy equivalence principle. The plastic damage model for the grouted connecting section is established; the stresses and deformation distribution of the steel pipes and grout in the connecting section are analyzed using the changed shear bond parameters. The results show that the rectangular and triangular shear bonds are more reasonable than the semicircular shear bond transfer. Increasing the height of the shear bond may reduce the maximum stress and the maximum vertical displacement of the grout, and the shear bond width change has less influence on the joint bond stress and displacement. [ABSTRACT FROM AUTHOR]

This study evaluated the mechanical behavior and risk of failure of three CAD-CAM crowns repaired with different resin composites through a three-dimensional (3D) finite element analysis. Three-dimensional models of different cusp-repaired (conventional nanohybrid, bulk-fill, and flowable resin composites) crowns made of zirconia, lithium disilicate, and CAD-CAM resin composite were designed, fixed at the cervical level, and loaded in 100 N at the working cusps, including the repaired one. The models were analyzed to determine the Maximum Principal and Maximum Shear stresses (MPa). Complementary, an in vitro shear bond strength test (n = 10) was performed to calculate the risk of failure for each experimental group. The stress distribution among the models was similar when considering the same restorative material. The crown material affected the stress concentration, which was higher for the ceramic models (±9 MPa for shear stress; ±3 MPa for tensile stress) than for the CAD-CAM composite (±7 MPa for shear stress; ±2 MPa for tensile stress). The shear bond strength was higher for the repaired CAD-CAM resin composite (±17 MPa) when compared to the ceramics (below 12 MPa for all groups), while the repair materials showed similar behavior for each substrate. The stress distribution is more homogenous for repaired resin composite crowns, and a flowable direct resin composite seems suitable to repair ceramic crowns with less risk of failure.

Composite slabs comprised of profiled steel sheets and concrete topping are the most common floor solution in composite building construction. The main advantages of this structural system are expected to be faster construction, removal of standard replaceable shuttering, and a reduction in the number of props required. The profiled steel sheets serve during the construction stage as a formwork instead of the traditional formwork. Later, when the concrete is cured, the profiled steel sheets work as the main reinforcement in the composite slabs. Longitudinal shear bond resistance is an important factor when designing composite slabs. PSC and m-k design approaches are considered the most often utilized methods for determining the shear bond capacity of the composite slabs. Four specimens of composite slabs in simply supported conditions were cast and tested in this study using a four-point bending test. In addition, shear span and thickness effects were studied. In this study, the shear bond capacity of the composite slabs was calculated using the m-k method. The experimental test data used in the linear regression analysis were plotted to predict the m-k values. The structural performance of composite slab specimens was evaluated using failure modes, load-deflection behavior, load-end slip behavior, and horizontal shear bond strength. The results suggested that specimens with greater thickness and shorter shear spans can withstand greater loads than specimens with greater thickness and longer shear spans, which may indicate that slenderness is a critical factor impacting the ultimate capacity of composite slabs. [ABSTRACT FROM AUTHOR]

This paper investigates the possible benefits and difficulties of using composite slabs, consisting of galvanized steel decks and in situ concrete, in reinforced concrete (RC) framed structures. Three different test arrangements were used. A four-point static test (quasi-test) has compared the flexural behavior of the proposed composite slab with traditional solid slab used with a RC beam under gravity load. The m–k values arrangement measures longitudinal shear to evaluate the composite action between the steel deck and the RC slab. The composite action between the RC beam and the composite slab has been examined by using a slip capacity test through four different cases. Results of the quasi-test, showed that both slabs had similar flexural behavior and capacity, while the proposed composite flange had higher total deflection but smaller crack widths than solid concrete flanges. The composite slab's m–k values were found acceptable compared to those in the literature. Longitudinal shear stress with a ductile mode of failure was observed in all specimens. In the slip capacity test, the concrete's shear forces were transferred by the concrete itself since the beam and slabs were monolithic, where no slip between the slabs and the beam was observed. Comparing the proposed composite slab with commonly known slabs (solid concrete one-way, two-way, joist, and flat slabs) emphasizes the proposed slab's ability to reduce the overall weight with the same load-carrying capacity, while speeding up the construction process. [ABSTRACT FROM AUTHOR]

This paper investigates the structural performance of a new two-way profiled steel decking system for steel-concrete composite slabs. Several studies have investigated steel decking for steel-concrete composite slabs and focused on utilising the conventional deck as a one-way floor system. The newly developed deck consists of top-hat sections formed by bending corrugated sheets at 90°, which are attached to a corrugated base sheet. The deck is designed for improved composite and two-way action contributed by its unique geometry due to corrugations in the transverse and longitudinal directions. This paper experimentally tested a novel steel decking geometry under construction stage loading. It was in the absence of concrete to establish the deck's suitability for construction and contribution towards loading capacity and performance for future use as a two-way composite slab. Ultimate load, two-way action, and failure modes were identified. A finite element model was also developed, and parameters assessed that could influence the performance when the deck is potentially used in the composite stage. It was concluded that, while increasing the thickness of the corrugated base sheet significantly affects the load-carrying capacity, the thickness of the top hats has no significant impact. Improved load transfer with two-way behaviour is observed when the bottom flanges of the top hats are continuously connected to the bottom flanges of the adjacent top hats to form a deck. This contrasts with the concept deck, where individual top hats are attached to a corrugated base sheet. In this case, decks with a corrugated base sheet perform 54% better in ultimate load capacity than decks without a corrugated base sheet. [ABSTRACT FROM AUTHOR]

Background: Bonding is an integral part of orthodontic treatment. Orthodontic bonding could be accomplished without the use of primer, it might be possible to reduce the risk of occupational exposure to primer and will save time. So it is very important to know whether primer is required or not. Aim: The aim of this study is to evaluate and compare the shear bond strength (SBS) of metallic and ceramic brackets bonded with and without primer application and to check for residual adhesive post debonding. Material and Method: A total of 100 extracted human premolar teeth were divided into 2 main groups A and B which were further subdivided into: Group A1 - metallic brackets bonded with primer; Group A2 - ceramic brackets bonded with primer; Group B1 - metallic brackets bonded without primer; group B2 - ceramic brackets bonded without primer. The SBS of these brackets was measured. Result: The SBS of group A2 was significantly higher than the other groups, group A1 was the second highest, group B3 was the third highest and group B4 was the least significant. The adhesive remnant index was lowest on failure of ceramic brackets bonded with primer. Conclusion: SBS of ceramic brackets bonded without primer is superior to SBS of metallic bracket bonded without primer and metallic brackets bonded with primer was superior than metallic bonded without primer. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of five porcelain repair systems on shear bond strength in composite and zirconia infrastructures and to identify the bond failure mode after thermocycling. Materials and Methods Disk-shaped zirconia samples (n=50) were divided into five groups (n=10) according to repairing system type. Each repair system was applied to the zirconium samples and a hybrid composite was used for repairing. Shear bond testing of all groups was carried out using a universal testing machine after thermocycling. Results Repair systems demonstrated no significant difference in repairing zirconia except Single Bond. Single Bond was the weakest in repairing the infrastructures. The highest and lowest mean bond strength values for the zirconia groups were 18,91 MPa and 3,63 MPa, respectively. Conclusion The three repair systems, Ivoclar, Clearfil, and Bisco, were more effective than the Single Bond and Ultradent repair systems in repairing zirconia, and their bond failure modes were both mixed and adhesive. [ABSTRACT FROM AUTHOR]

Introduction: The bond strength can be described as the most well-known success factor in layered all-ceramic crowns whereas the most common failure reason in the core-veneer interface is delaminating. This study aims at investigating the impact of various particle sizes of sandblasting on the roughness of the heat press (lithium di-silicate) core and shear bond strength between veneering ceramic and lithium disilicate core. Methods: Forty ceramic samples were divided into 4 types of surface treatments groups; 10without treatment (Control), the other 3 groups were treated by 50 µm AL2O3, 150 µm AL2O3, and 250 µm AL2O3 air borne particle abrasion respectively. The estimation of the roughness (nm) was made before and after treatment. Shear bond strength (MPa) and the mode of failure test was performed for all groups. In order for the data to be analyzed, a one-way ANOVA test and (LSD Test) were made for that purpose. Results:Sandblast group with 250µm AL2O3 had superior roughness and shear bond strength value, followed by the group treated with150µm AL2O3, the roughness of the group treated with50µm AL2O3 lower than 150µm AL2O3 and 250µm AL2O3. The control and sandblast with 50µm AL2O3 groups showing the same mean value in shear bond strength. Conclusion: Surface roughness and shear bond strength increased in group sandblast with 250µm AL2O3.The adhesive mode of failure was produced in (control, sandblast with 50 µm AL2O3) groups. The cohesive failure in (lithium di-silicate) core specimens produced in (sandblast with 250 µm AL2O3 and sandblast with 150 µm AL2O3) groups. [ABSTRACT FROM AUTHOR]

Aim: To analyze the influence of different surface pretreatments of zirconium dioxide reinforced lithium disilicate ceramics on the shear bond strength of self-adhesive resin cement. Materials and methods: Eighty-four zirconium reinforced lithium disilicate disc Vita suprinity (Vita Zahnfabrick, Bad Säckingen, Germany) 14x12x2 mm specimens were fabricated according to the manufacturer’s recommendations. The specimens were embedded in acrylic resin blocks and randomly divided in seven groups (n=12/each) accorrding to the treatment: Group 1- 10% hydrofluoric acid; Group 2- silane; Group 3- hydrofluoric and silane; Group 4- sandblasting with silane; Group 5- Er: YAG laser+ silane; Group 6- Nd: YAG laser + silane; and the control group, in which the specimens were not treated. Round shape composite discs (Filtek Bulk fill, 3M ESPE, St.Paul, Minnesota, USA) with 3.5 mm diameter, were made for shear bond strength testing, and then cemented to the ceramic sample surface using composite cement (RelyX U200 Automix, 3M ESPE, Neuss, Germany). After cementing the composite disc on the sample, the samples were subjected to shear bond strength test of 10 N with a “stress rate” of 1 MPa / s. To determine the nature of the fracture (adhesive, cohesive or adhesivecohesive), the broken samples were examined under a stereomicroscope. The ANOVA test and the Tukey test were used to compare the values of the bond strength characteristics between different types of materials. All tests were performed with a significance level of α = 0.05. Results: There was a significant difference in the shear bond strength of self-adhesive cement to dental lithium-disilicate ceramics reinforced with zirconium dioxide after different preparation protocols (p

Introduction: Intraoral repair has been suggested as a treatment option to repair the chipping or fracture of veneered zirconia; the success of the procedure is mainly determined by the bonding between zirconia and composite resin. The present study aimed to investigate and compare the shear bond strength (SBS) of two intraoral repair systems to zirconia ceramic treated with a laser or air-abrasion surface modification. Methods: Ninety tube-shaped samples (diameter of 10 mm and height of 4 mm) were divided into three main groups: Group I (zirconia 100%, n = 30); Group II (veneer ceramic 100% n = 30); Group III (zirconia with a veneer ceramic n = 30). Each main group was subdivided into two subgroups (n = 15): Subgroup A: samples repaired with Ceramic Repair N; Subgroup B: samples repaired with the Cimara Repair System. The subgroup samples were further subdivided based on the treated surface (n = 5 samples): Control (no surface modification), Er,Cr:YSGG laser surface modification, and air-abrasion surface modification. The SBS was employed using a universal testing machine. The mode of failure was observed using a stereomicroscope. Results: Significant differences were observed in the mean SBS values between the different surface modifications (P 0.05). Tukey's post hoc test showed that the air-abrasion surface modification of the veneer ceramic repaired with the Ceramic repair N system had the highest mean value (13.74 MPa) among the different groups, while no surface modification of zirconia repaired with the Cimara repair system had the lowest mean value (2.84 MPa). The control group (no surface modification) had the lowest mean value among all the treated groups. Conclusion: The SBS is surface modification-dependent, and higher SBS is obtained by air-abrasion than Er, Cr:YSGG laser surface modifications with the selected parameters. The Ceramic repair N system had significantly higher SBS for all surface-treated substrates than the Cimara repair system. [ABSTRACT FROM AUTHOR]

In recent years, offshore wind power has been developing rapidly, and single piles are among the commonly used foundations for wind turbines. Presently, experimental studies of the grouted connections of pile foundations are limited to the study of scaler models. Numerical simulations are more suitable for the mechanical analysis of the full-size structure instead of experimental ones. In numerical simulations, the linear elasticity model is widely adopted, but the plastic damage is studied scarcely. So, shear bond parameter research concerning grouted joints needs to be supplemented. In this paper, a bilinear random-motion reinforcement model based on the classical metal plasticity theory is adopted for steel, and the model for the grouting material is based on the Sidiroff energy equivalence principle. The plastic damage model for the grouted connecting section is established; the stresses and deformation distribution of the steel pipes and grout in the connecting section are analyzed using the changed shear bond parameters. The results show that the rectangular and triangular shear bonds are more reasonable than the semicircular shear bond transfer. Increasing the height of the shear bond may reduce the maximum stress and the maximum vertical displacement of the grout, and the shear bond width change has less influence on the joint bond stress and displacement.

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This paper investigates the structural performance of a new two-way profiled steel decking system for steel-concrete composite slabs. Several studies have investigated steel decking for steel-concrete composite slabs and focused on utilising the conventional deck as a one-way floor system. The newly developed deck consists of top-hat sections formed by bending corrugated sheets at 90°, which are attached to a corrugated base sheet. The deck is designed for improved composite and two-way action contributed by its unique geometry due to corrugations in the transverse and longitudinal directions. This paper experimentally tested a novel steel decking geometry under construction stage loading. It was in the absence of concrete to establish the deck’s suitability for construction and contribution towards loading capacity and performance for future use as a two-way composite slab. Ultimate load, two-way action, and failure modes were identified. A finite element model was also developed, and parameters assessed that could influence the performance when the deck is potentially used in the composite stage. It was concluded that, while increasing the thickness of the corrugated base sheet significantly affects the load-carrying capacity, the thickness of the top hats has no significant impact. Improved load transfer with two-way behaviour is observed when the bottom flanges of the top hats are continuously connected to the bottom flanges of the adjacent top hats to form a deck. This contrasts with the concept deck, where individual top hats are attached to a corrugated base sheet. In this case, decks with a corrugated base sheet perform 54% better in ultimate load capacity than decks without a corrugated base sheet.

Semi-precast-reinforced concrete slab system offers more economic method of construction as it minimises the need of formwork at site. The assembly of semi-precast slab system involves two steps: (1) casting of semi-precast slab at the yard and (2) overtopping of concrete at the site. One of the main factors that influence the performance of such slab system is the interface bonding between precast and overtopping concrete. Therefore, in order to better understand the performance of this slab system, a research was carried out to investigate the influence of surface treatment methodologies to the overall flexural behaviour through experimental and numerical studies. In total, five representative semi-precast slabs were constructed and tested to assess the flexural performance with different surface preparation methods and concrete overtopping. Further small-scale precast with overtopped concrete couplets and triplets were casted and tested as the representative semi-precast concrete slab types to examine the interface shear and tensile bond strength characteristics with those different surface treatments. The experimental results revealed that the surface treatment methods have influenced the flexural behaviour of the slabs, where the interface shear bond strength exceeds more than 1.0 MPa and the slab system behaves monolithically under flexural action. Moreover, numerical modelling technique for this slab system was developed based on the finite element framework to further analyse the overall flexural behaviour. Subsequently, good agreements between experimental and developed numerical model results were found. Finally, parametric analyses were performed to further assess the influences of concrete strengths, spans and reinforcement ratios on the safe imposed pressure applicable for this slab system. [ABSTRACT FROM AUTHOR]

One of the causes of dental caries that occurs due to orthodontic treatment is the lack of antibacterial properties in orthodontic adhesive. This study was designated to investigate the effect of orthodontic resin modified by incorporating Nano Cinnamon powder on the shear bond strength of orthodontic brackets. Heliosit Orthodontic Resin, a photo-activated light cure resin was modified by the addition of Cinnamon in the form of Nano particle powder. Twenty uniform disks were made, 5 as a control and 5 for each concentration of the 1%, 3% and 5% wt/wt Cinnamon modified resin. Their antimicrobial activity against Streptococcus Mutans was tested using the disk diffusion method. Then, the most effective concentration of the modified resin was used to bond metal orthodontic brackets to human extracted premolars. The universal testing machine was used to record the shear bond strength of the control and the modified resin. Also, the adhesive remnant index was measured. Disc diffusion method showed that the 3% wt/wt Cinnamon powder modified resin was more effective than 1% with a larger bacterial inhibition zone. Shear bond strengths of the control were 8.50 MPa and 7.20 MPa for the 3% Cinnamon modified resin with no significant difference between them. Also, no significant difference was recorded in the adhesive remnant index scores between the control and the modified resin groups. Findings of this study revealed that the incorporation of 3% Cinnamon Nano particles in orthodontic resin produced an antibacterial effect against Streptococcus mutans without compromising the shear bond strength. Incorporation of Cinnamon Nano particles in orthodontic resin may reduce caries formation around brackets during treatment course. [ABSTRACT FROM AUTHOR]

Purpose: This study was conducted to investigate the surface effects on dentin following laser "etching" with an Nd:YAG laser, and to determine the shear bond strengths of composite to untreated and laser-treated dentin. Materials and Methods: Dentin surfaces from freshly extracted permanent molars were subjected to laser treatment with an Nd:YAG laser. The results were analyzed using an SPSS/PC multiple range test. The shear bond strengths of laser-treated dentin/composite and untreated dentin/composite by dentin bonding were also determined. These results were also compared using the SPSS/PC multiple range test. Results: Shear bond strength in laser and acid groups were 6.70 ± 2.86 and 15.24 ± 8.51 MPa, respectively. Bond strength in the laser group was significantly lower than in the other group (p < 0.01). Conclusion: The Nd:YAG dental laser tested produced weaker shear bond strength than conventional acid etching. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effect of different adhesive luting systems on the shear bond strength of all-ceramic restorations to dentin surfaces. Materials and Methods: Forty-eight all-ceramic disks (2 x 3 mm; IPS e.max Press) were fabricated. Forty-eight noncarious extracted human molars were divided into 4 groups. In groups 1 to 4, IPS e.max Press disks were luted with Variolink 2/Excite DSC (etch-and-rinse), Clearfil Esthetic Cement/Clearfil Protect Bond (antibacterial and self-etching), Multilink/Multilink Primer (self-etching), or Multilink Sprint (self-adhesive). All specimens were subjected to 5000 thermocycles (5°C to 55°C, 30-s dwell time). Shear bond strengths were tested using a universal testing machine until failure. The analysis of the fractured dentin surfaces was performed using an optical microscope at 10X and 1000X magnification; the images were analyzed with an image analyzer. Data were analyzed with one-way ANOVA and Tukey's test at a significance level of p < 0.05. Results: Mean shear bond strength data of the groups in MPa were: Variolink 2/Excite DSC: 25.89 ± 3.71; Clearfil Esthetic Cement/Clearfil Protect Bond: 17.21 ± 2.71; Multilink/Multilink Primer: 11.6 ± 3.51; Multilink Sprint: 10.4 ± 3.15. According to the one-way ANOVA, there were significant differences in shear bond strength (p < 0.001). According to Tukey's test, statistically significant differences were observed in shear bond strength between groups 1 and 2 (p < 0.001), groups 1 and 3 (p < 0.001), groups 1 and 4 (p < 0.001), groups 2 and 3 (p = 0.003), and groups 2 and 4 (p < 0.001). Conclusion: The etch-and-rinse dentin bonding system produced higher bond strengths of all-ceramics to dentin surfaces than did the self-etching bonding systems and self-adhesive luting system. [ABSTRACT FROM AUTHOR]

• Formation of shear bond layer during FSAM of copper is analyzed. • Effects of shear bond layer on mechanical properties of FSAMed copper is evaluated. • Effects of shear bond layer on fracture morphology of FSAMed copper is evaluated. This study investigates the influence of the shear bond in friction stir additive manufacturing (FSAM) on the quality of printed copper sample. The shear bond is a mixture of thermo-mechanical affected zone (TMAZ) and re-heat affected zone (RAZ), formed around the ultra-fine grain region during FSAM. The shear bond is plays a crucial role in modifying the microstructure and mechanical properties of the printed layers. It is demonstrated that the presence of the shear layer enhances material strength, ductility, and fracture resistance, leading to improved overall quality of the printed samples. The microstructure size of the shear bond is 67.5% smaller than that of copper. This distinctive layer contributes to a notable 20% enhancement in the FSAM sample's performance. [ABSTRACT FROM AUTHOR]

Highlights • Finite element (FE) modeling of profiled steel composite slab with engineered cementitious composite (ECC) • Develop FE models using test results for novel ECC and self-consolidating concrete (SCC) slabs. • Parametric simulations by varying material/geometric and numeric parameters. Abstract This paper presents nonlinear finite element (FE) modeling of composite slab system comprising of profiled steel deck and high performance concrete namely, Engineered Cementitious Composite (ECC) and Self-Consolidating Concrete (SCC). FE models were developed and their performance validated based on experimental results of composite slabs subjected monotonic loading to failure. Parametric studies were conducted to investigate the influence of numerical/material/geometric parameters (such as mesh size, loading constraints, strain increment factor, steel sheet-concrete interaction contact types, concrete types, total/shear span length etc.) on FE model performance. Developed FE models were used to determine behavior of twenty two experimental composite slabs in validation and further validation with performance evaluation stages. The simulated load-deflection response, strength and shear bond capacity of FE model slabs were found to be in good agreement with those obtained from their experimental counterparts. [ABSTRACT FROM AUTHOR]

Background and Aim: Considering the increasing use of antibiotics in root canal therapy and the possible effects of intracanal medicaments on the bond strength of composite restorations, the aim of this study was to evaluate the effect of triple antibiotic paste (TAP) on shear bond strength of three types of composite resins to dentin. Materials and Methods: In this in-vitro, experimental study, the enamel of 60 extracted premolars was ground parallel to the longitudinal axis of the teeth in order to produce flat dentin surfaces (5 mm2 minimum surface area). The samples were divided into six groups. In the control group, dentin surfaces were stored in saline solution and in the experimental groups dentin surfaces were exposed to TAP for 10 days. After washing and drying, Single Bond was applied for dentin bond to Z100 and Z350 composites. Adhesive resin was used for bond to P90 composite. Composites were applied on the dentin surfaces in six groups and cured in four directions. The shear bond strength was measured by Instron machine. The data were analyzed by t-test, one-way ANOVA and Tukey’s test. Results: The highest mean shear bond strength was found in Z350 composite group following the use of TAP (38.75 MPa) and the lowest mean strength was found in Z100 composite group following the use of TAP (14.64 MPa). The mean shear bond strength of P90 and Z100 composites (in contrast to Z350 composite) was higher in the saline compared to the TAP groups (p=0.1). The differences between saline and antibiotic groups were not significant (p=0.959) but the difference in this regard among the three types of composites was significant. Conclusion: The results of this study showed that use of TAP has no effect on the shear bond strength of composite to dentin but the type of composite significantly affects the shear bond strength.

The study aimed to investigate the influence of surface treatments of Y-TZP on its topography and their impact on shear bond strength (SBS) of Y-TZP to veneering porcelain. Thirty-four zirconia cubes (Cercon) (10 × 10 × 10 mm3) were divided randomly into 3 groups (n = 11) according to the different surface treatments, Silica Coating (SC); Hot Solution Etching (HE); and Heat Treatment after porcelain glaze and powder application (GP). Porcelain application (IPs e.max) was performed after surface treatment using a standardized technique. Porcelain application (Ceramco-3) was also performed on 10 metal cubes (I BOND 2) as controls (MC). Specimens were subjected to thermocycling (5–55 °C, 20,000 cycles) followed by SBS testing in a universal testing machine. Surface topography was assessed by scanning electron microscopy and surface roughness (Image J). SC developed significantly higher SBS (42.10 ± 5.84 MPa) of Y-TZP to veneering ceramics compared to treatment by HE (24.0 ± 6.4 MPa), GP (23.30 ± 4.72), and the MC (29.3 ± 5.4 MPa) control (p < 0.05). SBS among HE, GP and MC specimens was comparable (p > 0.05). Y-TZP specimens treated with SC and HE showed high surface roughness compared to GP. Silicoating of Y-TZP prior to veneering can potentially reduce the high failure rates of zirconia-based restorations by enhancing the chemical bond between the core and the veneer materials. [ABSTRACT FROM PUBLISHER]

is to evaluate the effect of three different disinfectant solutions on shear bond strength of artificial acrylic teeth for retention to flexible denture base material at three different periods of time. Materials and Methods: The total number of samples was (60) divided into 4 groups according to the three chemical disinfectant solution which used and the control distilled water group: Group( I) vinegar group, Group( II) salt group , Group(III) Chlorohexidine group , Group (IV ) the control distilled water group, where each group was subdivided into three subgroups according to disinfection periods which are 1week, 1month and 3month where each group contain five samples. The samples of shear bond strength test were consist of acrylic teeth with T-shape design for retention attached to rod of valplast The test was performed using a Universal testing machine. ANOVA, DuncunP,Ps multiple range and Post Hoc Tests were carried out to determine the significant difference at p ≤ 0.01%. Results: The results appeared that control distilled water group has the highest value for the three periods of disinfection (1 week,1month,3months), while vinegar solution group has the least value. The results showed that there were significant differences between the four tested groups and also there were significant differences among all periods of time of disinfections. Conclusion: There was a significant difference of shear bond strength between artificial teeth and flexible denture base material after disinfection in the four disinfectant solutions for all periods of time of immersion. Vinegar group had highest effect on the bond strength while the distilled water group had the least effect after all periods of time of disinfections. Shear bond strength decreased with increasing the time immersion. The shear bond strength was lowest in chloherxidine group as the time of immersion increase when compared with the two other groups of disinfection solutions in this study.

Introduction: Adult patients typically require high-quality orthodontic treatment for ceramic brackets, but some clinicians remain concerned about the bond strength of these brackets. Therefore, the aim of this study was to determine the shear bond strength and de-bonding characteristics of metallic and ceramic brackets bonded with two types of bonding agents. Methods: In an experimental study done in 2013 in Babol, Iran, 120 extracted human maxillary premolar teeth were randomly divided into four groups as follows: HM group: metallic bracket/conventional bonding agent; SM group: metallic bracket/Transbond self-etching primer; HC group: ceramic bracket/conventional bonding agent; SC group: ceramic bracket/Transbond self-etching primer. Twenty-four hours after thermocycling (1000 cycle, 5 °C-55 °C), the shear bond strength values were measured. The amount of resin remaining on the tooth surface (adhesive remnant index: ARI) was determined under a stereomicroscope. Enamel detachment index was evaluated under a scanning electron microscope. To perform statistical analysis, ANOVA, Kruskal-Wallis, and Tukey post-hoc tests were applied. The level of significance was set at p <0.05. Results: The mean shear bond strength values (MPa ± SD) were group HM=12.59, group SM=11.15, group HC=7.7, and group SC=7.41. Bond strength differences between groups HM and SM (p=0.063) and between HC and SC (p=0.091) were not statistically significant. There were significant differences between HM and HC and between SM and SC groups (p < 0.05). Insignificant differences were found in ARI among all groups. Conclusion: Our findings indicated that the metallic brackets had higher bond strengths in comparison with ceramic brackets. In addition, self-etching primer was able to produce fewer bonds compared with the conventional technique. Many samples showed the bracket-adhesive interface failure or failure inside the adhesive. [ABSTRACT FROM AUTHOR]

Background and Aim : Development of new composite resins is one of the most important technological advances in the field of cosmetic dentistry. The aim of this study was to investigate the effectiveness of different light curing units and composite thicknesses on the shear bond strength composite to dentin . Materials and Methods : In this experimental in-vitro study, the test groups were composed of 80 dentinal samples, prepared on occlusal surfaces of 80 maxillary premolar teeth and routinely divided into 8 groups of 10. Two cylindrical molds (2×2 and 2×5 mm) were filled in bulk using P60 and Ceram X composites and light cured with LED and QTH light curing units .After curing and 3 months aging in 370c water, shear bond strength of all samples were obtained using a universal testing machine with 1mm/min crosshead speed. One- and three-way ANOVA were used for statistical analysis using SPSS software . Results : The highest mean of shear bond strength (31.75 MPa) was in group (P60, QTH, 2) and the lowest (15.34 MPa) was recorded in (Ceram X, LED, 5). Type and thickness of composites had significant effects on the value of shear bond strength and no significant differences were obtained between two light curing units . Conclusion : The shear bond strengths of P60 and CeramX composites tested were much lower when cured in a 5-mm than in a 2-mm increment. The two types of light curing units tested did not show any significant differences in the amount of shear bond strengths .

The aims of this in vitro study was to assess the effectiveness of various bur types and bonding agents on the shear bond strength of composite resin to dentin. Eighty non carious, extracted human molars were mounted in acrylic resin, the occlusal surface of all the teeth were grounded to obtain flat dentin surface. After that the teeth were randomly divided into four groups (n=20) according to the bur types that will be used to prepare the dentin surface. After preparation of dentin each group was divided into two subgroups (n=10) according to the type of adhesive systems used (Excite & I-Bond), the adhesive systems were applied to the dentin surface and light-cured according to manufacturers instructions. A 4mm high composite cylinder was incrementally built up. After that, specimens stored for one month at 37ºc in distilled water and thermo cycled for 500 cycles between (5ºc & 55ºc) and then tested in a universal testing machine. The results of this study demonstrated that the method of surface prepa-ration affected the shear bond strength of I-Bond and this is not true for Exit system, when the dentin surface prepared with fissure burs the shear bond strength greater than when the surface prepared with round burs. The results of this study also showed that the groups in which Excite bonding agent used have greater value of shear bond than the groups treated with I-Bond.

This research includes a theoretical investigation about the behaviour ofsimply supported composite slim floor beams with partial interaction. For thepurpose of analysis, the slim floor slab system is simplified to a multi-layeredcomposite beam. The slim floor beam is embedded in concrete. Therefore, thelayers of the slim floor are connected together by natural shear bondgenerated between the steel and concrete and distributed uniformly along theinterface without using shear connectors. Linear behaviour with one degree offreedom of the slim floor (slip only) without separation is studied according toJohnson and May approach using different material properties and differenttypes of loading.Equilibrium and compatibility are satisfied for the forces and displacementsat an assumed element to arrive at two differential equations of second-orderin terms of slip and axial force. The equations are solved numerically usingthe finite difference method. A computer program is written in Visual Basiclanguage to solve the problem.The current model is applied to three typical simply supported slim floorbeams tested experimentally by “Corus Construction Center”. The modelshowed close prediction with the observed results.

Eurocode 4 design provisions specify two methods for the design of composite slabs, namely the m-k and the partial shear connection (PSC) methods. Currently, the m-k method includes the concrete thickness and the shear span of the slab as variables while the PSC method does not. This has resulted in a better accuracy for the m-k method when slabs with varying dimensions are considered. It is demonstrated in this paper that the horizontal shear bond stress varies with the ratio of shear span to effective depth of slab, defined as the slenderness. To include such an effect, a linear shear bond-slenderness equation is proposed. Using the proposed relationship, a linear interpolation of shear bond strength based on two configurations, determined from the outcomes of the bending tests for compact and slender slabs, has been satisfactorily performed. The shear bond strength obtained from this interpolation can be used in collaboration with the existing PSC method, such that the accuracy of the prediction of the composite slab capacity can be considerably improved, the validity of which has been verified with published results from literatures.

Composite slab/flooring system known as fast track construction with profiled steel deck and regular concrete topping is very popular. This paper presents the development and performance evaluation of a new high performance composite flooring system incorporating emerging green cost-effective Engineered Cementitious Composites (ECCs). The high strain capacity while maintaining low crack widths makes fiber reinforced an ideal durable material for the composite floor construction. The proposed ECC based composite floors can resolve the problems associated with regular concrete based composite floors. Experimental investigations as per current Standard Specifications accompanied by Code based theoretical investigations were conducted to evaluate the structural performance of such flooring system in the construction and service stages. Thirty full-scale composite slabs were fabricated and tested under simply supported four-point loading conditions. The variables in the tests included: two types of concrete (a green cost-effective ECC and a commercial self-consolidating concrete ‘SCC’), two types of profiled steel sheet/deck, five different shear span and presence/absence of stud shear connectors. The structural performance of ECC based composite slabs was compared with their SCC counterparts based on load-displacement response, shear load resistance, failure modes, strain development in concrete/steel, load-slip behaviour, ductility, energy absorbing capacity and steel-concrete shear bond resistance. ECC composite slabs have shown superior performance compared with their SCC counterparts in terms of strength, ductility, energy absorbing capacity and shear bond resistance. [ABSTRACT FROM AUTHOR]

Ductility of reinforced structures is a desirable property where resistance to brittle failure during flexure is required. The most influential parameter towards the ductility value is the ratio of steel area to concrete area. However, the study on ductility performance of TWCF beam is still lacking. This paper aims is to reveal the ductility performance of Thin-Walled Composite-Filled Beam under flexural test. This paper presents a laboratory work which involves three samples of TWCF beams with different strength-enhancement devices. The effects of various modes interface connections are co-related to the generation of shear bond between sheeting and concrete, using both experimental and theoretical results. The strength and failure modes of the beams are found to be dependent on the interface connections. Analytical models for the ductility design of beams are developed and their performance is validated through experimental results using partial shear connection. The beams were designed by considering whether the strength will be governed by buckling or yielding of the steel plate. The analytical ductility model of TWCF beam shows a good agreement with the experimental result. [ABSTRACT FROM AUTHOR]

Aim: This study has compared the Shear Bond Strengths (SBSs) of ceramic brackets and metal brackets. Materials and Method: Forty freshly extracted, human maxillary first premolars were selected for bonding. They were equally bonded with ceramic brackets (Transcend series 6000) and metal brackets (Mini Dynalock Straight wire brackets). A no – mix orthodontic adhesive system was used. Their shear bond strengths were measured by using the Instron universal machine. Results: The mean bond strength of the ceramic brackets was 20.68 ± 3.89 Mpa and that of the metal brackets was 12.15 ± 1.32 MPa. Conclusion: The shear bond strength of the ceramic brackets was found to be superior than that of the metal brackets.

Eurocode 4 design provisions specify two methods for the design of composite slabs, namely them-kand the partial shear connection (PSC) methods. Currently, them-kmethod includes the concrete thickness and the shear span of the slab as variables while the PSC method does not. This has resulted in a better accuracy for them-kmethod when slabs with varying dimensions are considered. It is demonstrated in this paper that the horizontal shear bond stress varies with the ratio of shear span to effective depth of slab, defined as the slenderness. To include such an effect, a linear shear bond-slenderness equation is proposed. Using the proposed relationship, a linear interpolation of shear bond strength based on two configurations, determined from the outcomes of the bending tests for compact and slender slabs, has been satisfactorily performed. The shear bond strength obtained from this interpolation can be used in collaboration with the existing PSC method, such that the accuracy of the prediction of the composite slab capacity can be consider-ably improved, the validity of which has been verified with published results from literatures. [ABSTRACT FROM AUTHOR]

Resin-bonded fixed partial dentures (F.P.D) can be used for conservative treatment of partially edentulous"npatients. There are numerous studies regarding the strength of resin composite bond to base meta! alloys. Shear bond"nstrength of three resin systems were invistigated. In this study these systems consisted of: Panavia Ex, Mirage FLC and"nMarathon V. Thirty base metal specimens were prepared from rexillium III alloy and divided into three groups. Then each"ngroup was bonded to enamel of human extracted molar teeth with these systems. All of specimens were stored in water at"n37ac for 48 hours. A shear force was applied to each specimen by the instron universal testing machine. A statistical"nevaluation of the data using one-way analysis of variance showed that there was highly significant difference (P

Zirconium dioxide as core ceramic material for dental crowns and bridges, possess high strength, chemical stability and superior aesthetics after veneering. Veneering ceramic is considered to be the weakest part of all-ceramic restorations. The adhesion between the core and veneering porcelain is based on the manner in which the connection occurs in metal-ceramic structures. Standard procedures for connecting zirconia to hard dental tissues and veneering materials do not achieve the required strength of bonding. The aim of the paper is to investigate different surface treatments of the zirconium dioxide ceramic core and find the best, for achieving highest adhesive bonding values to veneering porcelain. The study was primarily designed to investigate the bonding strength of the veneering porcelain to zirconia with in vitro Macro shear bond strength test. The specimens with different surface treatment of the zirconia were divided in five groups of twelve according to the treatment of zirconium surface and results showed highest bonding values for specimens treated with Rocatec system. [ABSTRACT FROM AUTHOR]

Statement of Problem: The increase in the use of metal-ceramic restorations and a high prevalence of porcelain chipping entails introducing an alloy which is more compatible with porcelain and causes a stronger bond between the two. This study is to compare shear bond strength of three base-metal alloys and one noble alloy with the commonly used VMK Master Porcelain. Materials and Method: Three different groups of base-metal alloys (Ni-cr-T3, Super Cast, and VeraBond) and one group of noble alloy (X-33) were selected. Each group consisted of 15 alloy samples. All groups went through the casting process and change from wax pattern into metal disks. The VMK Master Porcelain was then fired on each group. All the specimens were put in the UTM; a shear force was loaded until a fracture occurred and the fracture force was consequently recorded. The data were analyzed by SPSS Version 16 and One-Way ANOVA was run to compare the shear strength between the groups. Furthermore, the groups were compared two-by-two by adopting Tukey test. Results: The findings of this study revealed shear bond strength of Ni-Cr-T3 alloy was higher than the three other alloys (94 MPa or 330 N). Super Cast alloy had the second greatest shear bond strength (80. 87Mpa or 283.87 N). Both VeraBond (69.66 MPa or 245 N) and x-33 alloys (66.53 MPa or 234 N) took the third place. Conclusion: Ni-Cr-T3 with VMK Master Porcelain has the greatest shear bond strength. Therefore, employment of this low-cost alloy is recommended in metalceramic restorations. [ABSTRACT FROM AUTHOR]

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Abstract: Relining of ill-fitting denture is often required to establish the fit of denture base, hence better retention and stability of the prostheses. However clinical success depends on the ability of reline resin to bond with denture base. The effect of surface preparations of urethane dimethacrylate (UDMA) denture base resin (Eclipse) on the shear bond strength (SBS) to auto-polymerizing polyethyl methacrylate reline material was evaluated. Eclipse specimens were mechanically prepared using two different tungsten carbide burs and submitted to chemical treatments either with dichloromethane (Secure adhesive) or methyl acetate (Eclipse Bonding Agent). Reline resin was then applied to the prepared surface and shear bond strength was tested after 24h. Data was analyzed using two-way ANOVA and post-hoc Tukey HSD test at p=0.05. The morphological changes of Eclipse surfaces after preparations were also observed under SEM. The results showed that SBS was significantly affected by mechanical roughening, chemical treatment and their interactions. Higher reline SBS values were observed for Eclipse specimens without mechanical roughening compared to those with roughening. Both chemical agents improved reline SBS with the highest bond strength shown when chemically treated using Secure adhesive. For mechanically roughened specimens, Eclipse Bonding Agent (BA) resulted in significantly higher reline bond strength than Secure adhesive. SEM showed different surface appearance of Eclipse resin with various mechanical and chemical preparations. [Copyright &y& Elsevier]

Objective: To evaluate the shear bond strength of precoated orthodontic brackets bonded with self-etching primer relative to that of noncoated conventionally-bonded brackets at two different time intervals. Methods: Twenty-one subjects were selected for randomized split-mouth bonding of two types of brackets to the maxillary arch. Half of the teeth had precoated brackets bonded using selfetching adhesive, and the other half had regular brackets bonded using Transbond XT adhesive. Nitinol wires were tied to the upper arch and were left until the time of debonding. The patients were randomly divided into two groups: one debonded after one hour and the other debonded two weeks after the initial wire placement. The shear bond strength was directly recorded from the patients' mouths using an in vivo debonding device. Results: There were no significant differences in shear bond strength between the precoated and conventional groups or within each group at different time intervals. There were significant differences between anterior and posterior teeth in both the precoated and conventional groups. Conclusion: Pre-coated brackets bonded with self-etching adhesive have the same bonding strength as the conventionally bonded brackets. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the shear bond strengths of light-polymerized urethane dimethacrylate (Eclipse) and heat-polymerized polymethylmethacrylate (Meliodent) denture base polymers to intraoral and laboratory-processed reline materials. Materials and Methods: Thirty disks measuring 15 mm diameter and 2 mm thick were prepared for each denture base material following the manufacturers’ recommendation. They were relined with Meliodent RR, Kooliner, and Secure reline materials after 1 month of water immersion. Ten additional Eclipse specimens were relined using the same Eclipse resin. A shear bond test was carried out on an Instron machine at a crosshead speed of 1.0 mm/min 24 hours after relining. Data were analyzed using two-way and one-way ANOVAs and post hoc Dunnett's T3 test ( p= 0.05). The nature of failure was analyzed under a stereomicroscope. The effect of dichloromethane adhesive on the two denture polymer surfaces and the failed interfaces of mixed and adhesive failures were analyzed under a SEM (scanning electron microscope). Results: Two-way ANOVA showed significant differences in the shear bond strength values as a function of the denture base polymers, reline materials, and their interaction ( p < 0.05). One-way ANOVA showed significant differences in shear bond strength values among denture base-reline combinations ( p < 0.05) except for Meliodent-Kooliner and Eclipse-Meliodent RR relines. Meliodent showed the highest shear bond strength value when relined with Meliodent RR (14.5 ± 0.5 MPa), and Eclipse showed the highest value with Eclipse relining (11.4 ± 0.6 MPa). Meliodent denture base showed adhesive, cohesive, and mixed failure, while all Eclipse showed adhesive failure with various reline materials. Conclusion: The two chemically different denture base polymers showed different shear bond strength values to corresponding reline materials. [ABSTRACT FROM AUTHOR]

Abstract: The Rankine formula has been adopted by many natural codes for designing columns and frames at ambient temperature. The method had recently been adapted for structural fire resistance prediction by Tan and co-workers [Tang CY, Tan KH. Basis and application of a simple interaction formula for steel frames under fire conditions. J Struct Engrg ASCE 2001;127(10):1206–13; Tang CY, Tan KH, Ting SK. Basis and application of a simple interaction formula for steel columns under fire conditions. J Struct Engrg ASCE 2001;127(10): 1214–20; Tan KH, Tang CY. Interaction formula for reinforced concrete columns in fire conditions. ACI Struct J 2004;101(1):19–28; Tan KH, Tang CY. Interaction model for unprotected concrete filled steel columns under standard fire conditions. J Struct Eng 2004;130:1405–13]. The conventional Rankine method considers a linear interaction of two failure modes: plastic squashing and linear elastic buckling, ignoring the coupling interaction between the two modes. Consequently, the conventional method gives lower bounds to actual failure loads. This paper discusses the physical meanings of the Rankine approach and the effect of coupling interaction (termed “shear bond” for consistency with our earlier publications) between the collapse modes on the ultimate failure load. The purpose is to demonstrate that the Rankine method is a conservative, robust, and rational method for the structural design of columns under either ambient or elevated temperatures. The approach can be further adapted to provide more accurate failure load predictions by incorporating the shear bond effect into the Rankine formula. Material deterioration at elevated temperature and the resulting effects on the strength and stability of columns are also quantified. A computer code (SAFIR), developed at the University of Liege, was used to calibrate the modified Rankine method. [Copyright &y& Elsevier]

Objective: To determine if a new premixed self-etch adhesive can be used to successfully bond orthodontic brackets to enamel. Materials and Methods: Forty human molars were cleaned, mounted, and randomly divided into two groups. In group 1, 20 teeth were conditioned using the self-etching primer Transbond Plus (3M Unitek, Monrovia, Calif). In group 2, 20 teeth were conditioned using a new premixed self-etching adhesive, AdheSE One (Ivoclar Vivadent Inc, Amherst, NY). Both groups were bonded using brackets precoated with a composite adhesive. The teeth were debonded within half an hour following initial bonding using a universal testing machine. After debonding, the enamel surface was examined under 10x magnifications to determine the amount of residual adhesive remaining on the tooth. A Student's t-test was used to compare the shear bond strength (SBS) of the two groups, and the Chi-square test was used to compare the adhesive remnant index (ARI) scores for the two adhesive systems. Results: The mean SBS of the brackets bonded to the teeth using AdhesSE One was 3.6 ± 1.3 MPa and was significantly lower (t = 2.80, P = .01) than the SBS of the brackets bonded using Transbond Plus (x̄ = 5.9 ± 3.2 MPa). The comparisons of the ARI scores between the two groups (χ² = 19.26) indicated that bracket failure mode was also significantly different (P < .001), with more adhesive remaining on the teeth bonded using Transbond Plus. Conclusions: The SBS of the new premixed self-etching adhesive needs to be increased for it to be successfully used for bonding orthodontic brackets. [ABSTRACT FROM AUTHOR]

Objective: To determine the influence of self-etching primer (SEP) application time on the shear bond strength of orthodontic brackets. Materials and Methods: Forty human molars were cleaned, mounted, and randomly divided into two groups. The same SEP, adhesive, and brackets were used in both groups. Twenty teeth were conditioned following the manufacturers' recommendations by rubbing the SEP on the enamel surface for 3 to 5 seconds. The remaining 20 teeth were conditioned using the same SEP, but the application time was increased to 15 seconds. The teeth were debonded within half an hour following initial bonding using a universal testing machine. After debonding, the amount of residual adhesive remaining on the tooth was determined. Student's t-test was used to compare the shear bond strength (SBS) of the two groups, and the χ² test was used to compare the Adhesive Remnant Index (ARI) scores for the two adhesive systems. Results: The mean SBS of the brackets bonded to the teeth subjected to the SEP for 3 to 5 seconds was 8.0 ± 4.6 MPa and was not significantly different (t = -0.69, P = .494) from the SBS of the brackets bonded using a 15-second SEP application time (x̄ = 8.9 ± 3.4 MPa). The comparisons of the ARI scores between the two groups (χ² = 2.16) indicated that bracket failure mode was not significantly different (P = .340) for both groups, and most failures were at the bracket-adhesive interface. Conclusion: The present findings indicate that increasing the SEP application from 3 to 5 seconds to 15 seconds does not result in a significant increase in SBS. [ABSTRACT FROM AUTHOR]

We present the results of experimental and numerical-analytic investigations of thin hardening films and discuss some methodological problems encountered in this case. We propose the relations for the evaluation of fracture stresses under cyclic bending and residual stresses taking into account the specific features of thin coatings, as well as a computational model for the prediction of cyclic strength depending on the thickness and type of the coatings. The accumulated experimental data confirm the indicated dependences. [ABSTRACT FROM AUTHOR]

Objectives. In this in vitro study, the effect of various drying (surface reaction) times of a commercial silane, other than that recommended by the manufacturer (at least 5 min), on the bond strength between the resin composite and silica coated base and noble alloys was evaluated.Methods. A total of 112 disc specimens (9 mm diameter and 0.5 mm thickness) were cast out of two types of alloy designed for ceramic firing, one of which was a noble (Degunorm) (gold–silver–platinum) and the other a base alloy (Wiron 99) (nickel–chromium–molybdenum). The specimens were assigned to two main groups according to each alloy type. These two main groups were further divided into seven subgroups, having eight specimens each. The specimens of both alloy types were air-abraded with 30 μm silica (SiO2) coated alumina (Al2O3) (CoJet®-Sand, ESPE, Seefeld, Germany). The conditioned surfaces were coated with 3-methacryloxypropyltrimethoxysilane (MPS) and were allowed to react and dry for 1, 2, 3, 4, 5, 6, and 7 min, respectively, before the opaquer was applied. Immediately after the waiting periods for the silane to dry, first opaquer and then resin composite were applied. After storage in water for 30 days at 37 °C and thermocycling (5000 cycles, 5–55 °C), shear tests were performed using the universal testing machine at a crosshead speed of 0.5 mm/min.Results. Analysis of data showed no significant difference in bond strength for any silane drying and reaction period for both base and noble alloys between 1 and 7 min (ANOVA, P=0.05) (Degunorm: 5.8–7.4 MPa and Wiron 99: 7.2–10.2 MPa, respectively). Bond strengths of resin composite to base alloys were significantly higher than those to noble alloys at 2, 3 and 5 min (P=0.0045, P=0.05, P=0.002, respectively).Significance. In order to optimize the flow of laboratory work, the silane solution drying time might be reduced to 1 min for both base and noble alloys. [Copyright &y& Elsevier]

With the introduction of photosensitive (light-cured) restorative materials in dentistry, various methods were suggested to enhance their polymerization and to shorten the curing time including layering and the use of more powerful light-curing devices. The purpose of this study was to determine the effect of using a new light-curing apparatus that uses a light-emitting diode (LED) on the shear bond strength of an orthodontic adhesive. The new light-curing apparatus used in the study was UltraLume 2 (Ultradent USA, South Jordan, Utah) that has an 8-mm footprint and can simultaneously cure two orthodontic brackets. Forty teeth were etched with 37% phosphoric acid, washed and dried, and sealant applied, and then precoated brackets with the Transbond adhesive (APC II, 3M Unitek, Monrovia, Calif) were placed. The teeth were randomly divided into two groups according to the curing light used. In group I (control), 20 brackets were cured using an Ortholux (3M Unitek) halogen curing light for 20 seconds. In group II, 20 brackets were cured using the new LED light for 20 seconds. The findings indicated no significant (P = .343) differences in the shear bond strength between the Ortholux halogen light (5.1 ± 2.5 MPa) and the UltraLume 2 LED light when the two groups were compared using Student's t-test (t = -0.961). In conclusion, the advantages of the new unit include the ability to cure two brackets at a time and a smaller light-emitting apparatus for the clinician to handle. [ABSTRACT FROM AUTHOR]