MyMedR

Fulltext Enhancement of the wear resistance and microhardness of aluminum alloy by Nd:YaG laser treatment

Hussein HT, Kadhim A, Al-Amiery AA, Kadhum AA, Mohamad AB

ScientificWorldJournal, 2014;2014:842062.

PMID: 25136694 DOI: 10.1155/2014/842062

Influence of laser treatment on mechanical properties, wear resistance, and Vickers hardness of aluminum alloy was studied. The specimens were treated by using Nd:YaG laser of energy 780 mj, wavelength 512 nm, and duration time 8 ns. The wear behavior of the specimens was studied for all specimens before and after treatment by Nd:YaG laser and the dry wear experiments were carried out by sing pinon-disc technique. The specimens were machined as a disk with diameter of 25 mm and circular groove in depth of 3 mm. All specimens were conducted by scanning electron microscopy (SEM), energy-dispersive X-ray fluorescence analysis (EDS), optical microscopy, and Vickers hardness. The results showed that the dry wear rate was decreased after laser hardening and increased Vickers hardness values by ratio of 2.4:1. The results showed that the values of wear rate for samples having circular grooves are less than samples without grooves after laser treatment.

Matched MeSH terms: Alloys/chemistry*

Fulltext Effect of multipath laser shock processing on microhardness, surface roughness, and wear resistance of 2024-T3 Al alloy

Kadhim A, Salim ET, Fayadh SM, Al-Amiery AA, Kadhum AA, Mohamad AB

ScientificWorldJournal, 2014;2014:490951.

PMID: 24737973 DOI: 10.1155/2014/490951

Laser shock processing (LSP) is an innovative surface treatment technique with high peak power, short pulse, and cold hardening for strengthening metal materials. LSP is based on the application of a high intensity pulsed laser beam (I > 1 GW/cm(2); t < 50 ns) at the interface between the metallic target and the surrounding medium (a transparent confining material, normally water) forcing a sudden vaporization of the metallic surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. The shock wave induces plastic deformation and a residual stress distribution in the target material. In this paper we study the increase of microhardness and surface roughness with the increase of laser pulse energy in 2024-T3 Al alloy. The influence of the thickness of the confining layer (water) on microhardness and surface roughness is also studied. In addition, the effect of LSP treatment with best conditions on wear behaviors of the alloy was investigated.

Matched MeSH terms: Alloys/radiation effects*; Alloys/chemistry*

Multidisciplinary treatment approach to restore deep horizontally fractured maxillary central incisor

Patil PG, Nimbalkar-Patil SP, Karandikar AB

J Contemp Dent Pract, 2014 Jan 1;15(1):112-5.

PMID: 24939276

This case report demonstrates sequential periodontic, orthodontic and prosthodontic treatment modalities to save and restore deep horizontally fractured maxillary central incisor. The location of fracture was deep in the mucosa which reveals less than 2 mm of tooth structure to receive the crown. The procedures like surgical crown lengthening, endodontic post placement, orthodontic forced eruption, core build-up and metal-ceramic crown restoration were sequentially performed to conserve the fractured tooth. Forced eruption is preferred to surgical removal of supporting alveolar bone, since forced eruption preserves the biologic width, maintains esthetics, and at the same time exposes sound tooth structure for the placement of restorative margins.

Matched MeSH terms: Metal Ceramic Alloys/chemistry

The effect of the surface roughness of porcelain on the adhesion of oral Streptococcus mutans

Al-Marzok MI, Al-Azzawi HJ

J Contemp Dent Pract, 2009;10(6):E017-24.

PMID: 20020077

Dental plaque has a harmful influence on periodontal tissue. When a porcelain restoration is fabricated and refinishing of the glazed surface is inevitable, the increase in surface roughness facilitates the adhesion of plaque and its components. The aim of this in vitro study was to evaluate the effect of surface roughness of glazed or polished porcelain on the adhesion of oral Streptococcus mutans.

Matched MeSH terms: Metal Ceramic Alloys*

A comparative evaluation of cleaning efficacy (debris and smear layer removal) of hand and two NiTi rotary instrumentation systems (K3 and ProTaper): a SEM study

Reddy KB, Dash S, Kallepalli S, Vallikanthan S, Chakrapani N, Kalepu V

J Contemp Dent Pract, 2013 Nov 1;14(6):1028-35.

PMID: 24858745

The present study was conducted to compare the cleaning efficacy (debris and smear layer removal) of hand and two NiTi rotary instrumentation systems (K3 and ProTaper).

Matched MeSH terms: Dental Alloys/chemistry*

Dental Alloy Adhesive Primers and Bond Strength at Alloy-Resin Interface: A Systematic Review and Meta-analyses

Ajay R, JafarAbdulla MU, Sivakumar JS, Baburajan K, Rakshagan V, Eyeswarya J

J Contemp Dent Pract, 2023 Aug 01;24(8):521-544.

PMID: 38193174 DOI: 10.5005/jp-journals-10024-3514

AIM: The present systematic review aimed to report the studies concerning the primers in improving bond strength and identifying pertinent primers for a particular dental alloy by adhering to PRISMA precepts.

MATERIALS AND METHODS: PubMed and Semantic Scholar databases were scoured for articles using 10 search terms. In vitro studies satisfying the inclusion criteria were probed which were meticulously screened and scrutinized for eligibility adhering to the 11 exclusion criteria. The quality assessment tool for in vitro studies (QUIN Tool) containing 12 criteria was employed to assess the risk of bias (RoB).

RESULTS: A total of 48 studies assessing shear bond strength (SBS) and 15 studies evaluating tensile bond strength (TBS) were included in the qualitative synthesis. Concerning SBS, 33.4% moderate and 66.6% high RoB was observed. Concerning TBS, 26.8% moderate and 73.2% high RoB was discerned. Seventeen and two studies assessing SBS and TBS, respectively, were included in meta-analyses.

CONCLUSIONS: Shear bond strength and TBS increased for the primed alloys. Cyclic disulfide primer is best-suited for noble alloys when compared with thiol/thione primers. Phosphoric acid- and phosphonic acid ester-based primers are opportune for base alloys.

CLINICAL SIGNIFICANCE: The alloy-resin interface (ARI) would fail if an inappropriate primer was selected. Therefore, the selection of an appropriate alloy adhesive primer for an alloy plays a crucial role in prosthetic success. This systematic review would help in the identification and selection of a congruous primer for a selected alloy.

Matched MeSH terms: Dental Alloys*

Predicting graded young modulus values of Ti alloys modified by ion implantation

Hassan MH

Med J Malaysia, 2004 May;59 Suppl B:164-5.

PMID: 15468869

There has been, and is still, concern about the high elastic modulus of Ti alloys compared to bone. Any reduction in the Young's modulus value of the implant is expected to enhance stress redistribution to the adjacent bone tissues, minimize stress shielding and eventually prolong device lifetime. Dynamic Monte Carlo simulation is used to predict the gradual reduction in Young's modulus values between the bulk of Ti alloys and the modified surface layers due to Ca ion implantation. The simulation can be used as a screening step when applying new alloys and/or coatings.

Matched MeSH terms: Alloys/analysis; Alloys/chemical synthesis*

Metallic materials stimulating bone formation

Kokubo T

Med J Malaysia, 2004 May;59 Suppl B:91-2.

PMID: 15468833

Metallic materials implanted into bone defects are generally encapsulated by a fibrous tissue. Some metallic materials such as titanium and tantalum, however, have been revealed to bond to the living bone without forming the fibrous tissue, when they were subjected to NaOH solution and heat treatments. Thus treated metals form bone tissue around them even in muscle, when they take a porous form. This kind of osteoconductive and osteoinductive properties are attributed to sodium titanate or tantalate layer on their surfaces formed by the NaOH and heat treatments. These layers induce the deposition of bonelike apatite on the surface of the metals in the living body. This kind of bioactive metals are useful as bone substitutes even highly loaded portions, such as hip joint, spine and tooth root.

Matched MeSH terms: Alloys

Properties of the tray adhesive of an addition polymerizing silicone to impression tray materials

Sulong MZ, Setchell DJ

J Prosthet Dent, 1991 Dec;66(6):743-7.

PMID: 1805022

Adhesive bond strength studies for the tray adhesive of an addition vinyl polysiloxane (President) impression material were conducted with an acrylic resin, chromium-plated brass, and plastic trays. Tensile and shear stress studies were performed on the Instron Universal testing machine. Acrylic resin specimens roughened with 80-grit silicon carbide paper exhibited appreciably higher bond strengths compared with different types of tray material and methods of surface preparation.

Matched MeSH terms: Alloys/chemistry

Metal-ceramic screw-retained implant fixed partial denture with intraoral luted framework to improve passive fit

Baig MR, Gunaseelan R

J Oral Implantol, 2012 Apr;38(2):149-53.

PMID: 20932151 DOI: 10.1563/AAID-JOI-D-09-00089

Passive fit of a long-span screw-retained implant prosthesis is an important criteria for the success of the restoration. This article describes a technique for fabricating a ceramometal implant fixed dental prosthesis (FDP) for a long-span partially edentulous situation by altering the conventional screw-retained design. The possibility of a passive fit is maximized by intraoral luting of the cast frame to milled abutments, and the potential framework distortion during fabrication is compensated to a major extent. Retrievability is ensured by screw retention of the prosthesis to the implants. Compared with conventional porcelain fused to metal screw-retained FDP, this prosthesis is relatively inexpensive to fabricate.

Matched MeSH terms: Metal Ceramic Alloys/chemistry*

Full-arch metal-resin cement- and screw-retained provisional restoration for immediately loaded implants

Baig MR, Rajan G

J Oral Implantol, 2010;36(3):219-23.

PMID: 20553176 DOI: 10.1563/AAID-JOI-D-09-00048

Abstract This article describes the clinical and laboratory procedures involved in the fabrication of laboratory-processed, provisional, screw-retained, implant-supported maxillary and mandibular fixed complete dentures incorporating a cast metal reinforcement for immediate loading of implants. Precise fit is achieved by intraoral luting of the cast frame to milled abutments. Effective splinting of all implants is attained by the metal substructure and retrievability is provided by the screw-retention of the prosthesis.

Matched MeSH terms: Chromium Alloys/chemistry; Dental Alloys/chemistry

Edentulous arch treatment with a CAD/CAM screw-retained framework and cemented crowns: a clinical case report

Baig MR, Rajan G, Rajan M

J Oral Implantol, 2009;35(6):295-9.

PMID: 20017646 DOI: 10.1563/AAID-JOI-D-09-00012R1.1

This article describes the rehabilitation of a completely edentulous patient using a milled titanium implant framework and cemented crowns. This combined approach significantly offsets unsuitable implant position, alignment, or angulation, while ensuring the easy retrievability, repair, and maintenance of the prosthesis. Hence, the dual advantage of cemented-retained crowns reproducing appropriate esthetics and function, irrespective of where the screw access openings are located in the substructure, can be obtained, along with the splinting effect and management of soft and hard tissue deficits achievable with a screw-retained framework.

Matched MeSH terms: Metal Ceramic Alloys/chemistry

Copper vapour laser ID labelling on metal dentures and restorations

Ling BC, Nambiar P, Low KS, Lee CK

J Forensic Odontostomatol, 2003 Jun;21(1):17-22.

PMID: 12793127

Denture marking is accepted as a means of identifying dentures and persons in geriatric institutions, or post-mortem during war, crimes, civil unrest, natural and mass disasters. Labelling on the acrylic resin component of the denture can easily be damaged or destroyed by fire but on cobalt-chromium components it would be more resistant. A copper vapour laser (CVL) can be used to label the cobalt-chromium components of dentures and metal restorations easily, and legibly, and miniaturised for the incorporation of more personal particulars necessary for the identification of the deceased person. The CVL beam is focussed by its optics and delivered to the material surface by the two-axis scanner mounted with mirrors. A personal computer controls the movement of the scanner and the firing of the CVL. The high peak power of the pulsed CVL is focussed to very high energy density producing plasma ablation of the alloy surface. Very fine markings of a few microns width can be produced enabling the storage of detailed information of the deceased person on a metal surface for the purpose of rapid identification.

Matched MeSH terms: Chromium Alloys/chemistry

Finite element analysis of zygomatic implants in intrasinus and extramaxillary approaches for prosthetic rehabilitation in severely atrophic maxillae

Ishak MI, Kadir MR, Sulaiman E, Kasim NH

Int J Oral Maxillofac Implants, 2013 May-Jun;28(3):e151-60.

PMID: 23748334 DOI: 10.11607/jomi.2304

To compare the extramaxillary approach with the widely used intrasinus approach via finite element method.

Matched MeSH terms: Dental Alloys

Remaining tooth structure associated with various preparation designs for the endodontically treated maxillary second premolar

Seow LL, Toh CG, Wilson NH

Eur J Prosthodont Restor Dent, 2005 Jun;13(2):57-64.

PMID: 16011232

Existing literature suggests a relationship between the amount of remaining tooth structure and the fracture resistance of the restored endodontically treated tooth. This study investigated the amount of tooth structure remaining following various tooth preparations used in the restoration of the endodontically treated maxillary second premolar. Illustrations of the maxillary second premolar in buccopalatal, mesiodistal and occlusal sections were drawn to scale. Outlines of various intra- and extracoronal preparations were superim-posed on the illustrations to reveal the amount of tooth tissue remaining in each case. Preparations for a ceramic inlay, inlay with palatal cusp coverage and onlay left 2.0-2.5mm of tooth structure buccally and palatally. Following preparation for a metal-ceramic crown, approximately 1.0mm of tooth structure remained buccally, and between 1.6mm-1.8mm palatally. Preparation for an all-ceramic crown was observed to leave 1.0mm-1.2mm of tooth structure surrounding what remained of the endodontic access cavity. It was concluded that decisions as to the type of definitive restoration to restore the endodontically treated maxillary second premolar may be influenced, amongst other factors, by information on the amount of tooth tissue remaining following preparation.

Matched MeSH terms: Metal Ceramic Alloys

Determination of silver, bismuth, cadmium, copper, iron, nickel and zinc in lead- and tin-base solders and white-metal bearing alloys by atomic-absorption spectrophotometry

Chong C

Talanta, 1986 Jan;33(1):91-4.

PMID: 18964038

A simple atomic-absorption spectrophotometry method is described for the determination of silver, bismuth, cadmium, copper, iron, nickel and zinc in lead- and tin-base solders and white-metal bearing alloys, with use of a single sample solution. The sample is dissolved in a mixture of hydrobromic acid and bromine, then fumed with sulphuric acid. The lead sulphate is dissolved in concentrated hydrochloric acid. The method is particularly suitable for the determination of silver and bismuth, which are co-precipitated with lead sulphate. The other elements can also be determined after removal of the lead sulphate by filtration.

Matched MeSH terms: Alloys

Fulltext Response Ant Colony Optimization of end milling surface roughness

Kadirgama K, Noor MM, Abd Alla AN

Sensors (Basel), 2010;10(3):2054-63.

PMID: 22294914 DOI: 10.3390/s100302054

Metal cutting processes are important due to increased consumer demands for quality metal cutting related products (more precise tolerances and better product surface roughness) that has driven the metal cutting industry to continuously improve quality control of metal cutting processes. This paper presents optimum surface roughness by using milling mould aluminium alloys (AA6061-T6) with Response Ant Colony Optimization (RACO). The approach is based on Response Surface Method (RSM) and Ant Colony Optimization (ACO). The main objectives to find the optimized parameters and the most dominant variables (cutting speed, feedrate, axial depth and radial depth). The first order model indicates that the feedrate is the most significant factor affecting surface roughness.

Matched MeSH terms: Alloys/chemistry

Fulltext Gold-Hybridized Zinc Oxide Nanorods as Real-Time Low-Cost NanoBiosensors for Detection of virulent DNA signature of HPV-16 in Cervical Carcinoma

Ramesh T, Foo KL, R H, Sam AJ, Solayappan M

Sci Rep, 2019 11 19;9(1):17039.

PMID: 31745139 DOI: 10.1038/s41598-019-53476-9

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.

Matched MeSH terms: Gold Alloys/chemistry

Fulltext An investigation of microstructural, magnetic and microwave absorption properties of multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4

Mustaffa MS, Azis RS, Abdullah NH, Ismail I, Ibrahim IR

Sci Rep, 2019 Oct 29;9(1):15523.

PMID: 31664142 DOI: 10.1038/s41598-019-52233-2

The enhancement of microwave absorbing properties in nickel zinc ferrite (Ni0.5Zn0.5Fe2O4) via multiwall carbon nanotubes (MWCNT) growth is studied in this research work. Ni0.5Zn0.5Fe2O4 was initially synthesized by mechanical alloying followed by sintering at 1200 °C and the microstructural, electromagnetic and microwave characteristics have been scrutinized thoroughly. The sintered powder was then used as a catalyst to grow MWCNT derived from chemical vapor deposition (CVD) method. The sample was mixed with epoxy resin and a hardener for preparation of composites. The composite of multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 shown a maximum reflection loss (RL) of -19.34 dB at the frequency and bandwidth of 8.46 GHz and 1.24 GHz for an absorber thickness of 3 mm for losses less than -10 dB. This acquired result indicates that multi-walled carbon nanotubes/Ni0.5Zn0.5Fe2O4 could be used as a microwave absorber application in X-band.

Matched MeSH terms: Alloys

Fulltext Tailoring bismuth borate glasses by incorporating PbO/GeO2 for protection against nuclear radiation

Kumar A, Jain A, Sayyed MI, Laariedh F, Mahmoud KA, Nebhen J, et al.

Sci Rep, 2021 Apr 08;11(1):7784.

PMID: 33833308 DOI: 10.1038/s41598-021-87256-1

Nuclear radiation shielding capabilities for a glass series 20Bi2O3 - xPbO - (80 - 2x)B2O3 - xGeO2 (where x = 5, 10, 20, and 30 mol%) have been investigated using the Phy-X/PSD software and Monte Carlo N-Particle transport code. The mass attenuation coefficients (μm) of selected samples have been estimated through XCOM dependent Phy-X/PSD program and MCNP-5 code in the photon-energy range 0.015-15 MeV. So obtained μm values are used to calculate other γ-ray shielding parameters such as half-value layer (HVL), mean-free-path (MFP), etc. The calculated μm values were found to be 71.20 cm2/g, 76.03 cm2/g, 84.24 cm2/g, and 90.94 cm2/g for four glasses S1 to S4, respectively. The effective atomic number (Zeff)values vary between 69.87 and 17.11 for S1 or 75.66 and 29.11 for S4 over 0.05-15 MeV of photon-energy. Sample S4, which has a larger PbO/GeO2 of 30 mol% in the bismuth-borate glass, possesses the lowest MFP and HVL, providing higher radiation protection efficiency compared to all other combinations. It shows outperformance while compared the calculated parameters (HVL and MFP) with the commercial shielding glasses, different alloys, polymers, standard shielding concretes, and ceramics. Geometric Progression (G-P) was applied for evaluating the energy absorption and exposure buildup factors at energies 0.015-15 MeV with penetration depths up to 40 mfp. The buildup factors showed dependence on the MFP and photon-energy as well. The studied samples' neutron shielding behavior was also evaluated by calculating the fast neutron removal cross-section (ΣR), i.e. found to be 0.139 cm-1 for S1, 0.133 cm-1 for S2, 0.128 cm-1 for S3, and 0.12 cm-1 for S4. The results reveal a great potential for using a glass composite sample S4 in radiation protection applications.

Matched MeSH terms: Alloys

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