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Silver-gold nanocrystalline films were sputtered on HDPE substrates by a physical vapour deposition process using alloys with a nominal composition of 65% silver/35% gold or 35% silver/65% gold by weight, with comparison to a 100% silver target. Novel process conditions were introduced to include both water and oxygen as reactive gases. X-ray diffraction and chemical digests were used to assess the structure and chemical composition of the films. Log reductions and corrected zone of inhibition tests were used to measure the biological properties. Despite a range of physical and chemical properties, biological tests showed that the bactericidal properties of all silver-gold films were comparable with silver-only films in the short term and 65% silver films made with Novel sputtering conditions had comparable bacteriostatic abilities to silver-only over a 7-day period. The benefit of including gold may be seen in future studies of anti-inflammatory activity., (© 2023 The Authors. International Wound Journal published by Medicalhelplines.com Inc and John Wiley & Sons Ltd.)

Detection of host integrated viral oncogenes are critical for early and point-of-care molecular diagnostics of virus-induced carcinoma. However, available diagnostic approaches are incapable of combining both cost-efficient medical diagnosis and high analytical performances. To circumvent this, we have developed an improved IDE-based nanobiosensor for biorecognition of HPV-16 infected cervical cancer cells through electrochemical impedance spectroscopy. The system is fabricated by coating gold (Au) doped zinc oxide (ZnO) nanorods interfaced with HPV-16 viral DNA bioreceptors on top of the Interdigitated Electrode (IDE) chips surface. Due to the concurrently improved sensitivity and biocompatibility of the designed nanohybrid film, Au decorated ZnO-Nanorod biosensors demonstrate exceptional detection of HPV-16 E6 oncogene, the cancer biomarker for HPV infected cervical cancers. This sensor displayed high levels of sensitivity by detecting as low as 1fM of viral E6 gene target. The sensor also exhibited a stable functional life span of more than 5 weeks, good reproducibility and high discriminatory properties against HPV-16. Sensor current responses are obtained from cultured cervical cancer cells which are close to clinical cancer samples. Hence, the developed sensor is an adaptable tool with high potential for clinical diagnosis especially useful for economically challenged countries/regions.

The nanomaterial landscape is so vast that a high-throughput combinatorial approach is required to understand structure-function relationships. To address this challenge, an approach for the synthesis and screening of megalibraries of unique nanoscale features (>10,000,000) with tailorable location, size, and composition has been developed. Polymer pen lithography, a parallel lithographic technique, is combined with an ink spray-coating method to create pen arrays, where each pen has a different but deliberately chosen quantity and composition of ink. With this technique, gradients of Au-Cu bimetallic nanoparticles have been synthesized and then screened for activity by in situ Raman spectroscopy with respect to single-walled carbon nanotube (SWNT) growth. Au 3 Cu, a composition not previously known to catalyze SWNT growth, has been identified as the most active composition., Competing Interests: Conflict of interest statement: K.A.B. and C.A.M. have financial interests in TERA-print, LLC, which could potentially benefit from the outcomes of this research. All other authors declare no competing interests.

Introduction: The efficacy of a chemotherapy drug in cancer therapy is highly determined by the ability to control the rate and extent of its release in vivo. However, the lack of techniques to accurately control drug release drastically limits the potency of a chemotherapy drug., Materials and Methods: Here, we present a novel strategy to precisely monitor drug release under magnetic stimulation. Methotrexate (MTX), an anticancer drug, was covalently functionalized onto iron-gold alloy magnetic nanoparticles (Fe-Au alloy nanoparticles or NFAs) through 2-aminoethanethiol grafting and the ability of this drug-nanoparticle conjugate (NFA-MTX) in limiting HepG2 (liver carcinoma) cell growth was studied. Well-dispersed NFAs were prepared through pyrolysis., Results and Discussion: Transmission electron microscopy revealed the average nanoparticle size to be 7.22±2.6 nm, while X-ray diffraction showed distinct 2θ peaks for iron and gold, confirming the presence of iron and gold nanoparticles. Inductively coupled plasma mass spectrometry revealed that the amount of NFA-MTX conjugate ingested by HepG2 cancer cells was 1.5 times higher than that ingested by L929 fibroblasts, thereby proving a higher selective ingestion by cancer cells compared to normal cells. Fourier-transform infrared spectroscopy revealed the breakage of Au-S bonds by the heat generated under magnetic field stimulation to release MTX from the NFA-MTX conjugate, triggering a 95% decrease in cellular viability at 100 µg/mL., Conclusion: The ability of NFA-MTX to dissociate under the influence of an applied magnetic field provides a new strategy to induce cancer cell death via hyperthermia. Applications in drug delivery, drug development, and cancer research are expected., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Aim: Herbs are used widely in medicine. The purpose of the present study was to assess the ion release from gold-plated orthodontic bracket compared with other stainless steel brackets, and based on the findings of the study, the orthodontists can choose the most biocompatible brackets and mouthwashes useful in the clinical practice., Materials and Methods: A total of 150 orthodontic brackets from Orthotechnology™ Company, USA (50 stainless steel one-piece brackets, 50 stainless steel two-piece brackets, and 50 gold brackets) were immersed in four mouthwashes in addition to distilled water. Ten of each type of brackets in every media were immersed under 37°C for 45 days. Ions released in these mouthwashes were measured, and comparisons among different bracket types and among various mouthwashes were done by one-way analysis of variance (ANOVA) and then with Games-Howell tests., Results: Increased amounts of ions released in herbal mouth-washes were recorded in gold and two-piece brackets in comparison with one-piece stainless steel brackets., Conclusion: Herbal mouthwashes must be used with caution as they showed an increased amount of ions released in comparison with chlorhexidine. One-piece stainless steel bracket system is the most compatible bracket type, as they released the least amount of ions., Clinical Significance: One-piece stainless steel brackets are better than two-piece brackets in terms of ions released.

In this work, a novel electrochemical detection platform was established by integrating molecularly imprinting technique with microfluidic chip and applied for trace measurement of three therapeutic drugs. The chip foundation is acrylic panel with designed grooves. In the detection cell of the chip, a Pt wire is used as the counter electrode and reference electrode, and a Au-Ag alloy microwire (NPAMW) with 3D nanoporous surface modified with electro-polymerized molecularly imprinted polymer (MIP) film as the working electrode. Detailed characterization of the chip and the working electrode was performed, and the properties were explored by cyclic voltammetry and electrochemical impedance spectroscopy. Two methods, respectively based on electrochemical catalysis and MIP/gate effect were employed for detecting warfarin sodium by using the prepared chip. The linearity of electrochemical catalysis method was in the range of 5×10 -6 -4×10 -4 M, which fails to meet clinical testing demand. By contrast, the linearity of gate effect was 2×10 -11 -4×10 -9 M with remarkably low detection limit of 8×10 -12 M (S/N=3), which is able to satisfy clinical assay. Then the system was applied for 24-h monitoring of drug concentration in plasma after administration of warfarin sodium in rabbit, and the corresponding pharmacokinetic parameters were obtained. In addition, the microfluidic chip was successfully adopted to analyze cyclophosphamide and carbamazepine, implying its good versatile ability. It is expected that this novel electrochemical microfluidic chip can act as a promising format for point-of-care testing via monitoring different analytes sensitively and conveniently., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The purpose of the current study was to evaluate the bonding performance of two single-liquid primers, which contained 6-(4-vinylbenzyl-n-propyl) amino-1,3,5-triazine-2,4-dithione (VTD) or 6-methacryloyloxyhexyl 2-thiouracil 5-carboxylate (MTU-6), used for bonding between metals and an acrylic resin. A gold alloy and high-purity titanium were used as adherend materials, and a transparent acrylic resin initiated with tri-n-butylborane derivative was selected as the luting material. Both adherends were treated with one of the primers and bonded with the luting material, after which shear bond strength was determined. Fourier transform infrared spectroscopy was used to analyze debonded resin specimens. Shear bond strength to gold alloy was significantly greater than that to titanium for both the VTD and MTU-6 primers. A trace of thiol structure, probably derived from VTD and MTU-6, was detected on resin surfaces debonded from gold alloy. These results indicate that the two organic sulfur compounds, which are stable in an atmospheric environment, are tautomerized into a thiol structure, thus allowing adsorption onto noble metals. In addition, the adsorbed thiol compounds contribute to chemical bonding between the acrylic resin and noble metal alloy, as polymerizable adhesive functional monomers.

A facile and green strategy is reported here to synthesize gold (Au), silver (Ag) and gold-silver (Au-Ag) alloy nanoparticles (NPs) through bio-reduction reactions of aqueous corresponding metal precursors mediated by extracts of aerial parts of R. hypocrateriformis, which act as both reducing and stabilizing agents, under microwave irradiation. UV-vis spectrophotometer, XRD, FT-IR, FESEM/TEM, TGA and EDAX analysis were used to characterize the obtained NPs. The formation of NPs is evident from their surface plasmon resonance peak observed at λ max =∼550, 450 and 500nm for Au, Ag and Au-Ag alloy NPs respectively. XRD pattern revealed that fcc structure, while FT-IR spectra signify the presence of phytochemicals adsorbed on NPs. Such a biofunctionalized NPs were characterized by their weight loss, 30% due to thermal degradation of plant phytochemicals observed in TG analysis. The spherical shape of Au, Ag and Au-Ag alloy NPs (∼10-50nm) is observed by FE-SEM/TEM images. EDAX analysis confirms the expected elemental composition. Moreover, these NPs showed enhanced antimicrobial, antioxidant, and anticancer activities, though it is more pronounced for Au-Ag alloy NPs, which is due to the combining effect of phytochemicals, Au and Ag metals. Thus, the biosynthesized NPs could be applied as effective growth inhibitors for various biomedical applications., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: We examined safety issues related to the presence of various metallic dental materials in magnetic resonance (MR) imaging at 7 tesla., Methods: A 7T MR imaging scanner was used to examine 18 kinds of materials, including 8 metals used in dental restorations, 6 osseointegrated dental implants, 2 abutments for dental implants, and 2 magnetic attachment keepers. We assessed translational attraction forces between the static magnetic field and materials via deflection angles read on a tailor-made instrument and compared with those at 3T. Heating effects from radiofrequency during image acquisitions using 6 different sequences were examined by measuring associated temperature changes in agarose-gel phantoms with a fiber-optic thermometer., Results: Deflection angles of the metallic dental materials were significantly larger at 7T than 3T. Among full metal crowns (FMCs), deflection angles were 18.0° for cobalt-chromium (Co-Cr) alloys, 13.5° for nickel-chromium (Ni-Cr) alloys, and 0° for other materials. Deflection angles of the dental implants and abutments were minimal, ranging from 5.0 to 6.5°, whereas the magnetic attachment keepers were strongly attracted to the field, having deflection angles of 90° or more. Increases in temperature of the FMCs were significant but less than 1°C in every sequence. The dental implant of 50-mm length showed significant but mild temperature increases (up to 1.5°C) when compared with other dental implants and abutments, particularly on sequences with high specific absorption rate values., Conclusion: Although most metallic dental materials showed no apparent translational attraction or heating at 7T, substantial attraction forces on the magnetic attachment keepers suggested potential risks to patients and research participants undergoing MR imaging examinations.

Objective: The aim of this in vitro study was to determine the load and deflection at failure of different lingual retainers bonded with composite to enamel in a standardized three-point bending test. The results were rationalized with finite element analysis (FEA) models., Materials and Methods: Four types of multistranded wires, Dead Soft Respond, Twisted ligature, Penta-One, Gold-plated Penta-One, and two glass fibre-reinforced composite retainers, Fibre 07 and Fibre 09, were bonded to enamel with composite and submitted to a three-point bending test. The load and deflection at failure and the mode of debonding were recorded. The stiffness of the wires was determined and all experimental data were used in FEA models to rationalize the observed values and mode of debonding., Results: Significant higher load and deflection were found for the most flexible retainers Twisted ligature and Dead Soft Respond. All retainers failed between the wire and composite, which was confirmed by FEA showing the highest stress in the composite around the retainer. The FEA models showed that the amount of composite used for bonding the retainers should be 2-4mm., Conclusions: Based on the in vitro results, optimal bonding of lingual retainers can be achieved by flexible retainers, bonded with intrinsically strong composites. According to the FEA models the retainer should be bonded with 2-4mm composite, leaving the critical 'free-wire' length for the success of the retainer system., (© The Author 2014. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Widespread use of silver nanoparticles raises questions of environmental and biological impact. Many synthesis approaches are used to produce pure silver and silver-shell gold-core particles optimized for specific applications. Since both nanoparticles and silver dissolved from the particles may impact the biological response, it is important to understand the physicochemical characteristics along with the biological impact of nanoparticles produced by different processes. The authors have examined the structure, dissolution, and impact of particle exposure to macrophage cells of two 20 nm silver particles synthesized in different ways, which have different internal structures. The structures were examined by electron microscopy and dissolution measured in Rosewell Park Memorial Institute media with 10% fetal bovine serum. Cytotoxicity and oxidative stress were used to measure biological impact on RAW 264.7 macrophage cells. The particles were polycrystalline, but 20 nm particles grown on gold seed particles had smaller crystallite size with many high-energy grain boundaries and defects, and an apparent higher solubility than 20 nm pure silver particles. Greater oxidative stress and cytotoxicity were observed for 20 nm particles containing the Au core than for 20 nm pure silver particles. A simple dissolution model described the time variation of particle size and dissolved silver for particle loadings larger than 9 μg/ml for the 24-h period characteristic of many in-vitro studies.

The catalytic reduction of methylene blue was studied using biosynthesised gold-silver (Au-Ag) alloy nanoparticles (NPs). The fungal biomass of Trichoderma harzianum was used as a reducing and stabilising agent in the synthesis of Au-Ag alloy NPs. The synthesised NPs were well characterised by UV-vis spectroscopy, dynamic light scattering, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The plausible synthesis mechanism involved in the formation of Au-Ag alloy NPs was also discussed with diagrammatic representation. A series of experiments was performed to investigate the catalytic activity of the as-prepared Au-Ag alloy NPs and found that the alloy NPs show excellent catalytic activity.

The present study was done to evaluate the effects of different types of abutments on the rate and distribution of stress on the bone surrounding the implant by dynamic finite element analysis method. In this study two ITI abutment models-one-piece and multi-piece-along with fixture, bone, and superstructure have been simulated with the help of company-made models. The maximum Von Mises stress (MVMS) was observed in the distobuccal area of the cortical bone near the crest of implant in two implant models. In the multi-piece abutment, MVMS was higher than the one-piece model (27.9 MPa and 23.3 MPa, respectively). Based on the results of this study, it can be concluded that type of abutment influences the stress distribution in the area surrounding the implant during dynamic loading.

Objectives: To investigate the composition and the microstructural and mechanical characterization of three different types of lingual brackets., Materials and Methods: Incognito™ (3M Unitek), In-Ovation L (DENTSPLY GAC) and STb™ (Light Lingual System, ORMCO) lingual brackets were studied under the scanning electron microscope employing backscattered electron imaging and their elemental composition was analysed by energy-dispersive X-ray microanalysis. Additionally, Vickers hardness was assessed using a universal hardness-testing machine, and the indentation modulus was measured according to instrumented indentation test. Two-way analysis of variance was conducted employing bracket type and location (base and wing) as discriminating variable. Significant differences among groups were allocated by post hoc Student-Newman-Keuls multiple comparison analysis at 95% level of significance., Results: Three different phases were identified for Incognito and In-Ovation L bracket based on mean atomic number contrast. On the contrary, STb did not show mean atomic contrast areas and thus it is recognized as a single phase. Incognito is a one-piece bracket with the same structure in wing and base regions. Incognito consists mainly of noble metals while In-Ovation L and STb show similar formulations of ferrous alloys in wing and base regions. No significant differences were found between ferrous brackets in hardness and modulus values, but there were significant differences between wing and base regions. Incognito illustrated intermediate values with significant differences from base and wing values of ferrous brackets., Conclusions/implications: Significant differences exist in microstructure, elemental composition, and mechanical properties among the brackets tested; these might have a series of clinical implications during mechanotherapy., (© The Author 2013. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To evaluate the effects of intraoral aging on surface properties of esthetic and conventional nickel-titanium (NiTi) archwires., Materials and Methods: Five NiTi wires were considered for this study (Sentalloy, Sentalloy High Aesthetic, Superelastic Titanium Memory Wire, Esthetic Superelastic Titanium Memory Wire, and EverWhite). For each type of wire, four samples were analyzed as received and after 1 month of clinical use by an atomic force microscope (AFM) and a scanning electronic microscope (SEM). To evaluate sliding resistance, two stainless steel plates with three metallic or three monocrystalline brackets, bonded in passive configuration, were manufactured; four as-received and retrieved samples for every wire were pulled five times at 5 mm/min for 1 minute by means of an Instron 5566, recording the greatest friction value (N). Data were analyzed by one-way analysis of variance and by Student's t-test., Results: After clinical use, surface roughness increased considerably. The SEM images showed homogeneity for the as-received control wires; however, after clinical use esthetic wires exhibited a heterogeneous surface with craters and bumps. The lowest levels of friction were observed with the as-received Superelastic Titanium Memory Wire on metallic brackets. When tested on ceramic brackets, all the wires exhibited an increase in friction (t-test; P < .05). Furthermore, all the wires, except Sentalloy, showed a statistically significant increase in friction between the as-received and retrieved groups (t-test; P < .05)., Conclusion: Clinical use of the orthodontic wires increases their surface roughness and the level of friction.

Objective: To test the hypothesis that there are no differences in mutans streptococci (MS) adhesion between esthetic and metallic orthodontic arch wires based on their surface characteristics., Materials and Methods: Surface roughness (Ra) and apparent surface free energy (SFE) were measured for six wires-four esthetic, one nickel-titanium (NiTi), and one stainless-steel (SS)-using profilometry and dynamic contact angle analysis, respectively. The amount of MS (Streptococcus mutans and Streptococcus sobrinus) adhering to the wires was quantified using the colony-counting method. The surfaces, coating layers, and MS adhesion were also observed by scanning electron microscopy. Statistical significance was set at P < .05., Results: The Ra values of the esthetic wires were significantly different from one another depending on the coating method (P < .05). The NiTi wire showed the highest SFE, followed by the SS wire and then the four esthetic wires. The NiTi wires produced a significantly higher MS adhesion than did the SS wires (P < .05). The esthetic wires showed significantly lower MS adhesions than did the NiTi wire (P < .05). Pearson correlation analyses found moderate significant positive correlations between the SFE and the S mutans and S sobrinus adhesions (r  =  .636/.427, P < .001/P  =  .001, respectively)., Conclusions: The hypothesis is rejected. This study indicates that some esthetic coatings on NiTi alloy might reduce MS adhesion in vitro in the short term.

When restoring a partially edentulous arch with an implant-supported fixed partial denture, the optimal fit and function of the final restoration depend on the fabrication of an accurate impression and the registration of the interocclusal relationship. The present case report presents a method for the fabrication of impressions and the registration of the interocclusal relationship for implant-supported partial dentures. The described method allows the accurate transfer of the implant position and the registration of the interocclusal relationship using transfer key and electroformed gold copings. The key and copings were used to transfer the intraoral implant position to the cast, to position the abutments intraorally, and to facilitate the fabrication of the final partial denture.

The study compared the marginal accuracy of premade and cast abutments. Premade titanium, stainless steel, and gold abutments formed the control groups. Plastic abutments were cast in nickel-chromium, cobalt-chromium and grade IV titanium. The abutment/implant interface was analyzed. Analysis of variance and Duncan's multiple range test revealed no significant difference in mean marginal microgap between premade gold and titanium abutments and between premade stainless steel and cast titanium abutments. Statistically significant differences (P < .001) were found among all other groups.

Objective: To compare the corrosion behavior of commercially available surface modified nickel titanium (NiTi) arch wires with respect to a conventional NiTi and to evaluate its association with surface characteristics., Materials and Methods: Five types of surface modified arch wires and a conventional NiTi arch wire, all from different manufacturers, were evaluated for their corrosion resistance from breakdown potential in an anodic polarization scan in Ringer's solution. Surface characteristics were determined from scanning electron microscopy, atomic force microscopy, and energy dispersive analysis. One-way analysis of variance and post hoc Duncan's multiple range tests were used to evaluate statistical significance., Results: Surface modified NiTi wires showed significant improvement in corrosion resistance and reduction in surface roughness values. Breakdown potentials increased in the order of group 6 (conventional; 204 mV) < group 1 (nitride; 333 mV) < group 5 (epoxy resin; 346mV) < group 3 (oxide; 523 mV) < group 2 (gold; 872 mV) < group 4 (Teflon; 1181 mV), but root mean square (RMS) roughness values, which indicated surface roughness, followed a different pattern: group 3 (oxide; 74.12 nm) < group 1 (nitride; 221.651 nm) < group 4 (Teflon; 278.523 nm) < group 2 (gold; 317.894 nm) < group 5 (epoxy resin; 344.236 nm) < group 6 (conventional; 578.555 nm)., Conclusions: Surface modification of NiTi wires proved to be effective in improving its corrosion resistance and decreasing surface roughness. However, neither factor could maintain a direct, one-to-one relationship. It meant that the type and nature of coating material can effectively influence the anticorrosive features of NiTi wires, compared with its surface roughness values.

This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Zirconia blocks (N=240; 6 mm×7 mm×7 mm) were manufactured from two materials namely, ICE Zirconia (Group 1) and Prettau Zirconia (Group 2). In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid (shade A2). Three different veneering ceramics with different TEC (ICE Ceramic, GC Initial Zr and IPS e.max Ceram) were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys (Esteticor Plus) veneered with ceramic (VM 13) (n=16) acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine (0.5 mm⋅min(-1)). Neither the zirconia core material (P=0.318) nor colouring (P=0.188) significantly affected the results (three-way analysis of variance, Tukey's test). But the results were significantly affected by the veneering ceramic (P=0.000). Control group exhibited significantly higher mean bond strength values (45.7±8) MPa than all other tested groups ((27.1±4.1)-(39.7±4.7) and (27.4±5.6)-(35.9±4.7) MPa with and without colouring, respectively) (P<0.001). While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering <1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered >1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.

Background: The final esthetic outcome of a metal-ceramic restoration is influenced by several factors including the type of the underlying metal as well as the brand of the ceramic., Settings and Design: An in vitro study., Aims: The purpose of the in vitro study was to investigate the influence of four types of metal-ceramic alloys and two porcelain systems on the color co-ordinates of the metal-ceramic complex. It also aimed at establishing a color index which correlated the color of the metal-ceramic combination to the yellow-blue axis., Materials and Methods: Twenty-four disc-shaped metal specimens of 12 mm × 1 mm were cast from base metal alloys, nickel-chromium (Ni-Cr) (Wiron 99), cobalt-chromium (Co-Cr) (Wirobond C), a palladium (Pd)-rich noble metal alloy (Spartan Plus), and a high noble gold (Au) alloy (Pontostar). These discs were covered with two commercially available feldspathic porcelains (Vita Omega and Shofu Vintage) of A3 shade to a total thickness of 1.2 mm. Each group had six specimens, of which three were coated with Vita Omega and the remaining with Shofu Vintage. Opaque and dentin layers were applied to a standardized thickness of 0.2 mm ± 0.05 mm and 1 mm ± 0.05 mm, respectively onto the metal surface after air abrasion with 50 μm alumina particles. The reflectance spectra were measured with a spectrophotometer and data were recorded in L*, a* and b* coordinates in the CIE Lab Color Order System., Statistical Analysis: Analysis of variance (ANOVA) and path analysis were the statistical tools employed to analyze the data. A critical difference (CD) value was calculated for each color co-ordinate to make comparisons between each metal-ceramic combination. A color index for each metal-ceramic complex was also calculated from the color co-ordinates obtained., Results: ANOVA revealed that significant differences existed between the metal-porcelain combination at 0.01 ( P < 0.01) level. The L* value was significantly higher for Au and Co-Cr alloys with Vita Omega porcelain. The a* value was highest for Ni-Cr alloy when combined with Shofu Vintage ceramic. The b* value of Au alloy with Vita Omega porcelain was significantly higher than any other metal-ceramic combination. The color co-ordinates of Pd alloy with both porcelain systems did not show any significant differences. Gold alloy with Vita Omega showed the highest color index value., Conclusion: The variations in metal-ceramic alloy and porcelain can influence the shade of a metal-ceramic restoration. Color index value was the highest for gold alloy.

Ab initio method based on density functional theory at PW91PW91 level has been applied in studying the geometrical structures, relative stabilities, and electronic properties of small bimetallic Au(n)Be(+) (n = 1-8) cluster cations. The geometrical optimizations indicate that a transition point from preferentially planar (two-dimensional) to three-dimensional (3D) structures occurs at n = 6. The relative stabilities of Au(n)Be(+) clusters for the ground-state structures are analyzed based on the averaged binding energies, fragmentation energies, and second-order difference of energies. The calculated results reveal that the AuBe(+) and Au(5)Be(+) clusters possess higher relative stability for small size Au(n)Be(+) (n = 1-8) clusters. The HOMO-LUMO energy gaps as a function of the cluster size exhibit a pronounced even-odd alternation phenomenon. Sequently, the natural population analysis and polarizability for our systems have been analyzed and compared further.

Objective: To determine the effect of coating on the properties of two esthetic orthodontic nickel-titanium wires., Materials and Methods: Woowa (polymer coating; Dany Harvest) and BioForce High Aesthetic Archwire (metal coating; Dentsply GAC) with cross-section dimensions of 0.016 × 0.022 inches were selected. Noncoated posterior regions of the anterior-coated Woowa and uncoated Sentalloy were used for comparison. Nominal coating compositions were determined by x-ray fluorescence (JSX-3200, JOEL). Cross-sectioned and external surfaces were observed with a scanning electron microscope (SEM; SSX-550, Shimadzu) and an atomic force microscope (SPM-9500J2, Shimadzu). A three-point bending test (12-mm span) was carried out using a universal testing machine (EZ Test, Shimadzu). Hardness and elastic modulus of external and cross-sectioned surfaces were obtained by nanoindentation (ENT-1100a, Elionix; n  =  10)., Results: Coatings on Woowa and BioForce High Aesthetic Archwire contained 41% silver and 14% gold, respectively. The coating thickness on Woowa was approximately 10 µm, and the coating thickness on BioForce High Aesthetic Archwire was much smaller. The surfaces of both coated wires were rougher than the noncoated wires. Woowa showed a higher mean unloading force than the noncoated Woowa, although BioForce High Aesthetic Archwire showed a lower mean unloading force than Sentalloy. While cross-sectional surfaces of all wires had similar hardness and elastic modulus, values for the external surface of Woowa were smaller than for the other wires., Conclusions: The coating processes for Woowa and BioForce High Aesthetic Archwire influence bending behavior and surface morphology.

Aim: Thermal analysis of the temperature and stress distribution of parallel sided, threaded and non-threaded dowels and core materials under thermal loading within a maxillary central incisor using a three dimensional finite element study., Materials and Methods: 3D models of endodontically treated maxillary central incisor with parallel sided, threaded and non- threaded post and core materials were simulated using the ANSYS software. Materials simulated were parallel sided cast gold post and core, parallel sided fibre reinforced composite (FRC) post and core, and parallel sided, threaded, prefabricated stainless steel post and amalgam core. Thermal loads simulating hot (60 degree C/ 333K) and cold (15 degree C/288K) liquid were applied for 15 seconds at the incisal edge. The temperature changes at the selected nodes were obtained on the various post and core materials, interface between post and dentin, interface between core and dentin, within the dentin and within the cement layer., Results: Temperature and stress distribution pattern were represented in numerical and color coding and results interpreted. Thermal stresses arises as a result of temperature changes. A decreased temperature gradient of the metallic dowels and core (T1 hot - 0.002K, T3 hot - 1.071K, T1 cold -0.99K, T3 cold - 0K) were obtained than that of the FRC dowel and core of 1.982K(hot) and1.55K(cold) respectively due to the higher thermal conductivity of the metals. Higher thermal stress values of 3.567 Mpa(hot) and 3.092 Mpa(cold) respectively were obtained for the FRC dowels and higher stress values of 39.679 Mpa(hot) and 57.855 Mpa(cold) respectively were also obtained for the FRC cores. These values indicated that thermal stresses of the FRC dowel and core were greater than that of cast gold dowel and core and prefabricated stainless steel dowel and amalgam core due to its high coefficient of thermal expansion. Maximum stress values of the FRC dowel and core of 1.87 Mpa(hot) and 2.57 Mpa(cold) respectively were also generated in the cement layer, core and metal ceramic crown. The junction of the metal ceramic crown and dentin demonstrated the maximum stress. Higher thermal stress values of 59.162 ± 10 Mpa were obtained in the restoration and the coronal portion of the dentin than the stress levels of .0039 ± 10 Mpa in the supporting bone due to an increased thermal expansion., Conclusion: Non-metallic dowel and core materials such as fibre reinforced composite dowels (FRC) generate greater stress than metallic dowel and core materials. This emphasized the preferable use of the metallic dowel and core materials in the oral environment.

The objective of this study was to investigate the effects of precuring of primer coated on bracket bases on the strength of bonds between metal brackets and gold alloy. Square type III gold alloy plates were sandblasted with 30 μm silicon dioxide. After silica coating, excessive particles were removed gently with air. Silane was then applied, and maxillary central incisor metal brackets were bonded to each conditioned alloy surface with Transbond XT. Half of the specimens were precured at the bracket base after primer coating and the other half was not precured before bonding to the alloy surface. After bracket positioning, samples were cured using a light emitting diode (LED) for 40 seconds. Shear bond strengths were tested and adhesive remnant index (ARI) was evaluated after 1 hour and 24 hours. The primer precuring and 24 hours group exhibited highest bond strength (12.53 MPa) and the no precuring and 1 hour group showed lowest bond strength (5.58 MPa). Precured groups showed lower ARI scores. Due to the shallow curing depth of LED light and inhibition of transillumination at the metal surface, primer precuring at the bracket base is required for secure bracket bonding on gold alloy surfaces using LED curing units.

Objective: Intraoral corrosion of dental alloys has biological, functional, and esthetic consequences. Since it is well known that the salivary urea concentrations undergo changes with various diseases, the present study was undertaken to determine the effect of salivary urea concentrations on the corrosion behavior of commonly used dental casting alloys., Materials and Methods: Three casting alloys were subjected to polarization scans in synthetic saliva with three different urea concentrations., Results: Cyclic polarization clearly showed that urea levels above 20 mg/100 ml decreased corrosion current densities, increased the corrosion potentials and, at much higher urea levels, the breakdown potentials., Conclusion: The data indicate that elevated urea levels reduced the corrosion susceptibility of all alloys, possibly through adsorption of organics onto the metal surface. This study indicates that corrosion testing performed in sterile saline or synthetic saliva without organic components could be misleading.

The aim of this research was to evaluate the effect of individual metallic elements within experimental Au-Pt-based metal-ceramic alloys on in vitro biocompatibility. A binary Au-10 at.% Pt alloy (AP10) was designed as a parent alloy. Six ternary AP10-X (X = In/Fe/Sn/Zn) alloys and four quaternary (AP10-In2)-Y (Y = Fe/Sn/Zn) with different compositions were cast into square plates with size 10X10X0.5 mm(3) and subjected to porcelain-firing thermal cycling. A commercial alloy was used as a control. In vitro biocompatibility was investigated using L929 murine aneuploid fibrosarcoma cell line. The test samples and cells were incubated at 37°C in a 5% CO(2) atmosphere for 72 h. Alamar™ Blue Assay was carried out to determine the respiratory viability of cultures maintained in the presence of the different materials. The cell only control showed significantly higher levels of cell viability than all six of the ternary alloys and two of the four quaternary alloys, (AP10-In2)-Zn2.1 and (AP10-In2)-Sn1.0 (P < 0.05). The quaternary alloys showed slightly higher levels of cell viability than the ternary alloys, with the exception of AP10-Sn0.9. No statistical differences were seen between the ternary and quaternary alloy groups. Acceptable cell viability was observed on the surfaces of all the alloys.

The aim of this study was to investigate the clinical outcome of removable partial dentures (RPDs) designed to minimize denture mobility during function. Using archived files of the undergraduate program between 2003 and 2005 at Tokyo Medical and Dental University, a list of 169 patients treated with 184 RPDs was created. The RPDs had either an acrylic resin-base or a cobalt-chrome framework-base. Two examiners telephoned all the listed patients and interviewed 118 patients (70%) regarding the use of their RPDs. Of 118 patients, 42 (36%) had stopped using, mainly due to problems with abutment teeth in resin-based dentures, and replacement in cobalt-chrome-based dentures. There was no significant difference in mean age, gender distribution, mean number of remaining/abutment teeth, distribution of denture arch, and Kennedy classification between denture use and nonuse groups (p>0.05). The nonuse group showed a significantly higher percentage of resin-base compared to the use group (p = 0.006). Logistic regression analysis indicated that resin-base was a significant risk factor for nonuse (p = 0.008). The present findings suggest that abutment teeth should be selected carefully, especially in this type of resin-based RPDs, and that the denture base material may be a critical factor which determines denture use.

The question whether Au can alloy with Pt at the nano-scale size is still controversial. By performing density functional theory calculations for several small Au/Pt bimetallic clusters Au(m)Pt(n) (m + n = 4-6, 13), we find that, in all the most stable geometries, Pt atoms prefer to assemble together to form the core while Au atoms like to surround the Pt atoms to form the shell, and that evenly mixed clusters are structurally unstable. The unique geometric characteristics can be explained by analyzing the different electronic properties of Pt-Pt, Au-Pt and Au-Au bonds, and is expected also to apply to larger Au/Pt bimetallic clusters.

The density functional method with relativistic effective core potential has been employed to investigate systematically the geometrical structures, relative stabilities, growth-pattern behaviors, and electronic properties of small bimetallic M(2)Au(n) (M = Ag, Cu; n = 1-10) and pure gold Au(n) (n ≤ 12) clusters. The optimized geometries reveal that M(2) substituted Au(n+2) clusters and one Au atom capped M(2)Au(n-1) structures are dominant growth patterns of the stable alloyed M(2)Au(n) clusters. The calculated averaged atomic binding energies, fragmentation energies, and the second-order difference of energies as a function of the cluster size exhibit a pronounced even-odd alternation phenomenon. The analytic results exhibit that the planar structure Ag(2)Au(4) and Cu(2)Au(2) isomers are the most stable geometries of Ag(2)Au(n) and Cu(2)Au(n) clusters, respectively. In addition, the HOMO-LUMO gaps, charge transfers, chemical hardnesses and polarizabilities have been analyzed and compared further.

The aim of this in vitro study was to investigate the influence of enamel moisture on the shear bond strength (SBS) of a hydrophobic resin cement, Maximum Cure (MC), and a self-adhesive resin cement, Multilink Sprint (MLS), after etching of the enamel. Forty cylindrical gold alloy rods were used to simulate the Incognito lingual bracket system. They were bonded to the enamel of 40 human teeth embedded in self-cured acrylic resin. Twenty were bonded with MC (10 on dry and 10 on wet enamel) and 20 with MLS (10 on dry and 10 on wet enamel). The SBS of MC and MLS was determined in a universal testing machine and the site of bond failure was defined by the adhesive remnant index (ARI). A Kruskal-Wallis test was performed followed by Games-Howell post hoc pairwise comparison tests on the SBS results (P < 0.05) and a chi-square test was used for the analysis of ARI scores (P < 0.05). On dry enamel, no significant differences between MC (58 +/- 5 MPa) and MLS (64 +/- 13 MPa) were noted. On wet enamel, the adherence of MC (6 +/- 8 MPa) and MLS (37 +/- 13 MPa) significantly decreased but to a lesser extent for MLS. The ARI scores corroborated these results. In conclusion, MC did not tolerate moisture. MLS was also affected but maintained sufficient adherence.

Objective: Evaluation of the color change of a semileucent ceramic system with different core-veneer thicknesses and backgrounds., Materials and Methods: Thirty disk-shaped specimens with different thicknesses of core-veneer were prepared with IPS-Empress 2 and IPS-Eris glass ceramic and four backgrounds were prepared., Results: Color differences were significantly influenced by total ceramic thicknesses and backgrounds (p < 0.001)., Conclusion: Thickness and backgrounds caused a detectable color mismatch in clinically relevant core-veneer thicknesses of IPS Empress 2.

In this study, the corrosion resistance of Ag-Au-Cu-Pd system alloys consisting of 5 or 10 mass% indium was evaluated. Levels of element release and tarnish were determined and electrochemical measurements performed. Results were compared with those for commercial silver-palladium-gold alloy. In terms of electrochemical behavior, the transpassive potential of these experimental alloys was 168-248mV. Experimental alloys with 25 mass% Au showed similar corrosion resistance to control gold-silver-palladium alloy. Amount of released elements was 14-130microg/cm(2) at 7 days, which is in the allowable range for dental alloys. Addition of indium to Ag-Au-Cu-10mass%Pd system alloys was effective in increasing resistance to tarnish and alloys containing 10 mass% of indium showed a minimal decrease in L(*) values after immersion. These findings indicate that 25Au-37.5Ag-15Cu-10Pd-2Zn-10In-0.5Ir alloy is applicable in dental practice.

This study evaluated the influence of retorque on loosening torque (Lt) of prosthetic screws in implant-supported dentures with different fit levels. Ten mandibular implant-supported dentures were fabricated and then 20 cast models were then prepared using prosthetic structures to create 2 fit levels: passive fit (Pf) and misfit (Mf). Two tightening techniques were also evaluated: initial torque only (T1); and initial torque and retorque after 10 min (T2). Gold or titanium screws were used, resulting in 4 groups to each one: Pf/T1, Pf/T2, Mf/T1, Mf/T2. The Lt was measured 24 h after the tightening torque using digital torque meter. Data were analyzed statistically by two-way ANOVA and Tukey's test (alpha=0.05), separately for each screw material. For titanium screws, no significant difference (p>0.05) was found between Pf/T1 and Pf/T2, or between Pf/T2 and Mf/T2. However, statistically significant difference (p<0.05) was found between Pf/T1 and Mf/T1, and between Mf/T1 and Mf/T2. Mf reduced the Lt using T1, while and T2 increased the Lt for Mf. Retorque and fit were shown to have no significant influence on the Lt of the gold screws. Retorque application made insignificant the misfit effect on the Lt of the titanium screws, suggesting that this procedure should be performed routinely during the screw tightening in multi-unit dentures.

This report addresses maxillary restoration with removable telescopic crown-retained palatal free dentures. One patient with 7 natural teeth (PERIO), a second patient with 6 dental implants (IMPL), and a third patient with 2 natural teeth and 4 dental implants (IMPL-PERIO) were treated. Zirconia copings for natural teeth and individual zirconia implant abutments were fabricated in CAD/CAM and used as primary crowns. Electroformed gold copings were used as secondary telescopes. All maxilla supraconstructions were fabricated with zirconia and CAD/CAM. Patients were monitored during a 3-year period; all teeth and implants survived, and no biological or mechanical complications occurred. The peri-implant and periodontal conditions were healthy. While recognizing the limitations of this report, results showed that fabricating removable zirconia structures by means of CAD/CAM can yield highly functional and esthetic results. Galvanoforming technology is the preferable means of fabricating secondary crowns. The combination of these techniques and materials results in a prosthetic reconstruction of high quality, good fit, and biocompatibility. Long-term studies of large populations are necessary to investigate the clinical properties of the material utilized in this type of construction.

Near infrared (NIR) absorbing Au-Au(2)S nanoparticles were modified with surfactants of different hydrocarbon chain lengths to allow loading of anticancer drug, cisplatin. The interfacial interactions and surfactant chain length effects on drug loading, optical properties and cytotoxicity were discussed in this work. Short-chain surfactants were oriented closer to the surface normal and were adsorbed at higher densities. Surface modification also changed the optical properties of the particles. Notably, particles modified with short-chain surfactants exhibited a red shift, whereas particles modified with long-chain surfactants showed a blue shift. The in vitro cytotoxicity of drug-loaded surface-modified particles was dependent on the surfactants' chain length. Significant cytotoxicity was observed for 1 mg/ml of drug-loaded particles using surfactants with the shortest chain length. After NIR triggered drug release, the released Pt compounds were observed to be cytotoxic, while remaining nanoparticles did not exhibit any cytotoxicity. Also, the released Pt compounds upon NIR irradiation of drug-loaded particles were observed to be more toxic and had a different molecular structure from cisplatin.

Objectives: As the choice of suprastructure alloy to be combined with titanium for the oral cavity is still a much debated issue, the aim of this study was to investigate the electrochemical interaction of the suprastructure/implant couples under the determined experiment conditions., Material and Methods: The potentiodynamic polarization curves and open-circuit potentials (OCP) of four UCLA type suprastructures coupled with straight Swiss Plus implant fixtures were taken in Afnor type artificial saliva solution at 37 degrees C. The concentration of ions leached into artificial saliva solutions was estimated with ICP-MS. SEM images of the margins of suprastructure/implant couples were obtained before and after the electrochemical tests., Results: The OCP value of titanium became passive at the most negative potential. The lowest difference between the initial and constant OCP value was exhibited by the Au based suprastructure. Suprastructures made greater contributions to the potentiodynamic polarization curves of the implant/suprastructure couples. According to the ICP-MS results, Pd based and Au based couples dissolved less than Co-Ni based and Co-Cr based couples., Conclusions: Within the conditions this study, it may be concluded that the titanium implant forms a stable passive oxide layer in artificial saliva exposed to open air and does not affect the corrosion properties of the suprastructures. Pd based and Au based couples have been found to be more corrosion-resistant than base alloy couples.

This study evaluated the influence of water storage conditions and the effect of metal priming agents on bond strength and durability of four luting agents joined to gold alloy. Disk specimens were cast from a gold alloy (Degudent U), and the surfaces were ground flat with abrasive paper. Three surface conditions employed were: unprimed, primed with Alloy Primer, and primed with Metaltite. Three resin-modified glass ionomers (RMGIs; Vitremer Luting Cement, Fuji Lute, and Xeno Cem Plus) and a resin adhesive (Super-Bond C&B) were used for bonding the gold alloy. Unprimed specimens bonded either with Fuji Lute or with Super-Bond C&B were immersed in water at 5, 37, and 55 degrees C for 7 days, or subjected to thermocycling (5,000 cycles; 5 degrees C, 1 min and 55 degrees C, 1 min). In addition, specimens were bonded with 12 combinations comprising three surface conditions and four luting agents, and thermocycled for 20,000 cycles. Shear bond strengths were then determined and analyzed statistically. Thermocycling was useful for evaluation of the bonding durability of RMGIs. Application of two metal priming agents combined with RMGIs considerably enhanced the bond strength to the gold alloy.

The aim of the present study was to design and fabricate a maxillary posterior fixed partial denture (FPD) made of a type 4 gold alloy and an indirect composite. Unlike the conventional framework design of a resin veneered restoration, cut-back was extended approximately 1/4 to 1/3 width in the occlusal table of the buccal cusp. Multiple retentive beads 150-200 mum in diameter were placed on the metal surface to be veneered. The gold alloy was cast in a cristobalite mold using a centrifugal casting machine. The cut surface with the retentive beads was air-abraded with alumina, and a priming agent (Alloy Primer) that contained triazine dithione monomer (VTD) was applied. A tooth-colored veneer was then fabricated with a highly loaded light- and heat-cured composite material (Estenia). This design and procedure can be applied as a standardized laboratory technique for fabrication of maxillary posterior restorations and FPDs.

Several authors still consider the mechanical problems of fracture and component loosening as the main causes of failure of implant-supported restorations. The purpose of this in vitro study was to compare the preload of three types of screw for transmucosal abutment attachment used in single implant-supported prosthesis through strain gauge and removal torque measurements. Three external hex fixtures were used, and each received a transmucosal abutment (Cera One), which was fixed to the implant with its respective screw: Group A- gold screw, Group B- titanium screw and Group C- surface-treated titanium screw (Ti-Tite). Ten screws of each type were attached applying a 30.07+/-0.28 Ncm torque force and maintained in position for 5 minutes. After this, the preload values were measured using strain gauges and a measurement cell. Gold screws presented higher preload values (131.72+/-8.98 N), followed by surface-treated titanium screws (97.78+/-4.68 N) and titanium screws (37.03+/-5.69 N). ANOVA (p<0.05) and Tukey's test (p<0.05) were applied. Statistically significant differences were found among the groups for both preload and removal torque values. In conclusion, gold screws may be indicated to achieve superior longevity of the abutment-implant connection and, consequently, prosthetic restoration due to greater preload values yielded.

Understanding how clinical variables affect stress distribution facilitates optimal prosthesis design and fabrication and may lead to a decrease in mechanical failures as well as improve implant longevity. In this study, the many clinical variations present in an implant-supported prosthesis were analyzed by a 3-dimensional finite-element method. The anterior segment of a human mandible treated with 5 implants supporting a curved beam was created to perform the tests. The variables introduced in the computer model were cantilever length, elastic modulus of cancellous bone, abutment length, implant length, and framework alloy (AgPd or CoCr). The computer was programmed with physical properties of the materials as derived from the literature, and a 100-N vertical load was used to simulate the occlusal force. Images with fringes of stress were obtained, and the maximum stress at each site was plotted in graphs for comparison. Stresses tended to be concentrated at the cortical bone around the neck of the implant closest to the load, whereas stresses in cancellous bone were considered low. In general, the stress distribution was better with stiffer cancellous bone, longer abutments and implants, and shorter cantilevers. The use of a CoCr alloy framework appears to contribute to a better stress distribution.

Carbon supported Pt-Au catalysts with different bimetallic compositions were prepared by water in oil (w/o) microemulsion. Carbon Vulcan XC-72 was added during the synthesis of particles in order to obtain their good dispersion and a mean particle size distribution of 5.02 +/- 0.56 nm. Structural characterization was performed using XRD at wide angles (WAXS), which showed that Pt-Au particles exhibited alloy properties. Electrochemical characterization allowed to estimate the surface composition of Pt-Au alloys, which was close to that of the bulk material Pt(20)Au(80). This catalyst composition displayed the best catalytic activity in steady-state conditions in comparison with Pt(50)Au(50) or Pt and Au alone. Moreover, a Pt-Au/C catalyst with a metal loading of 40 wt % was immobilized onto a carbon porous tube as anode. A membrane-less biofuel cell was tested using laccase/ABTS biocathode in phosphate buffer (pH 5).

Age-hardening behavior during continuous heating in commercial dental casting gold alloys was investigated by means of electrical resistivity measurements, hardness tests and X-ray diffraction. Two distinguishable behaviors were detected. It is considered that the difference was attributed to the amount of platinum, and the atomic ratio of gold and copper in each alloy. The phase transformations during continuous heating progressed into two steps (stages I and II). Increase of the platinum addition in gold-based alloys retards the rate of the reaction and decreases remarkably the amount of stage I.

The age-hardening behaviors of a low gold dental alloy were studied by means of differential scanning calorimetry, hardness testing, X-ray diffraction, optical microscopy and transmission election microscopy. Two distinct hardening behaviors were found at two different aging temperatures. Age-hardening at 290 degrees C was attributed to the formation of the metastable AuCuI' ordered phase, and the gradual softening in the overaging stage resulted from the slow growth of this phase. The rapid increase in hardness in the early stage at 495 degrees C was due to the precipitation of the metastable AuCuI' or/and AuCuII' ordered phases, and the rapid decrease in hardness in the overaging stage was a consequence of the growth of these phases and the loss of the coherency strain at the interface between the spindal-like AuCuI platelets and the matrix.

Automatic qualitative analysis for peak identification is a standard feature of virtually all modern computer-aided analysis software for energy dispersive X-ray spectrometry with electron excitation. Testing of recently installed systems from four different manufacturers has revealed the occasional occurrence of misidentification of peaks of major constituents whose concentrations exceeded 0.1 mass fraction (10 wt%). Test materials where peak identification failures were observed included ZnS, KBr, FeS2, tantalum-niobium alloy, NIST Standard Reference Material 482 (copper-gold alloy), Bi2Te3, uranium-rhodium alloys, platinum-chromium alloy, GaAs, and GaP. These misidentifications of major constituents were exacerbated when the incident beam energy was 10 keV or lower, which restricted or excluded the excitation of the high photon energy K- and L-shell X-rays where multiple peaks, for example, Kalpha (K-L2,3)-Kbeta (K-M2,3); Lalpha (L3-M4,5)-Lbeta (L2-M4)-Lgamma (L2-N4), are well resolved and amenable to identification with high confidence. These misidentifications are so severe as to properly qualify as blunders that present a serious challenge to the credibility of this critical analytical technique. Systematic testing of a peak identification system with a suite of diverse materials can reveal the specific elements and X-ray peaks where failures are likely to occur.

Purpose: The aim of our study was to explore the effects of different loading positions on the movements of the abutment tooth and denture base of removable partial denture with unilaterally designed framework (RPD-U)., Materials and Methods: The experiment was carried out with a simulation model of a mandible without left molars. The movements of abutment tooth and denture base of the unilateral and bilateral designs were due to 30N vertical load on 12 loading positions determined with a strain gauge circuitry. The effects of loading positions on the movements of the abutment tooth and denture base were compared between two designs., Results: During the loading on buccal, lingual positions, and the most disto-central position the movements of the abutment tooth and denture base of the unilateral design were significantly greater than those of the bilateral design (P < 0.01). During the loading on the three mesio-central positions the movements of the abutment tooth and denture base were equal between designs, and were significantly lower than during the loading on the other positions (P < 0.01)., Conclusion: Ending the denture teeth at the mesial cusp of second molar and positioning the occlusal contacts over the ridge crest adequately stabilize the abutment tooth and denture base of RPD-U.

Commercial low-gold dental casting alloy composed of Ag-Pd-In-Au-Zn was studied to clarify the age-hardening mechanism and related microstructural changes. The hardness of solution-treated specimen began to increase and reached the maximum value with ageing time, and then the maximum hardness value decreased by further ageing. The changes of X-ray diffraction (XRD) pattern during isothermal ageing revealed that the age hardening was not caused by phase transformation. By comparing the age-hardening curve with the changes in full-width at half-maximum of the XRD peaks at each ageing time, it was revealed that the coherency strains were formed in the Ag-rich matrix, which contributed to the hardness increase during ageing. From scanning electron microscopic observation and electron probe microanalysis, it was clarified that fine particle-like structures composed of InPd containing small amount of Zn gathered by diffusion in the Ag-rich matrix, and the coherency strains which formed during that time caused the hardness increase in the early stage of age-hardening process. The coherency strains were released by the progress of coarsening of Zn-containing InPd dendrite during further ageing, which caused the overaging in the later stage of age-hardening process.

Synthesis of the novel Cu@Au alloy nanoparticle and its application in an electrochemical DNA hybridization detection assay is described in this article. We report a low-temperature method for generating core-shell particles consisting of a core of Cu and a thin layer of Au shell that can be readily functionalized with oligonucleotides. Core-shell Cu@Au particles were successfully labeled to a 5'-alkanethiol capped oligonucleotides probe that is related to the colitoxin gene. The DNA genetic sensing assay relies on the electrostatic adsorption of target oligonucleotides onto conducting polypyrrole (PPy) surface at the glassy carbon electrode (GCE), and its hybridization to the alloy particle-oligonucleotides DNA probe. Hybridization events between probe and target were monitored by the release of the copper metal atoms anchored on the hybrids by oxidative metal dissolution and the indirectly determination of the solubilized Cu2+ ions by sensitive anodic stripping voltammetry (ASV). The detection limit is 5.0 pmol l(-1) of target oligonucleotides. The Cu@Au core-shell nanoparticles combining the surface modification properties of Au with the good electrochemical activity of Cu core shows their perspective application in the electrochemical DNA hybridization analysis assay.