Displaying publications 1 - 20 of 136 in total

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  1. Abu Bakar NH, Abu Bakar M, Bettahar MM, Ismail J, Monteverdi S
    J Nanosci Nanotechnol, 2013 Jul;13(7):5034-43.
    PMID: 23901527
    A detailed study on the surface properties of oleic acid-stabilized PtNi nanoparticles supported on silica is reported. The oleic acid-stabilized PtNi nanoparticles were synthesized using NaBH4 as the reducing agent at various temperatures and oleic acid concentrations, prior to incorporation onto the silica support. X-ray diffraction studies of the unsupported oleic acid-stabilized PtNi particles revealed that the PtNi existed as alloys. Upon incorporation onto silica support, surface properties of the catalysts were investigated using H2-temperature reduction (H2-TPR), H2-temperature desorption (H2-TPD) and H2-chemisorption techniques. It was found that for the bimetallic catalysts, no oxides or very little oxidation occurred. Furthermore, these catalysts exhibited both Pt and Ni active sites on its surface though the availability of Ni active sites was dominant. A comparison of the surface properties of these materials with those prepared without oleic acid in our previous work [N. H. H. Abu Bakar et al., J. Catal. 265, 63 (2009)] and how they affect the hydrogenation of benzene is also discussed.
    Matched MeSH terms: Alloys/chemistry
  2. Adam Husein, Huwaina Abd. Ghani, Fazal Reza
    MyJurnal
    Replacing a single missing anterior tooth can be a challenge. Many factors need to be considered when choosing the appropriate treatment. Several treatment options are well established. This case report is to present the use of a cast cobalt chrome partial denture with custom made porcelain tooth to improve aesthetic. The overall shade of the artificial tooth were nicely matched with the adjacent teeth and definite enamel translucency could be achieved which would not be possible with acrylic or even with readymade porcelain tooth.
    Matched MeSH terms: Chromium Alloys
  3. 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*
  4. Akhtar MN, Khan M, Khan SA, Afzal A, Subbiah R, Ahmad SN, et al.
    Materials (Basel), 2021 May 18;14(10).
    PMID: 34070060 DOI: 10.3390/ma14102639
    In the present investigation, the non-recrystallization temperature (TNR) of niobium-microalloyed steel is determined to plan rolling schedules for obtaining the desired properties of steel. The value of TNR is based on both alloying elements and deformation parameters. In the literature, TNR equations have been developed and utilized. However, each equation has certain limitations which constrain its applicability. This study was completed using laboratory-grade low-carbon Nb-microalloyed steels designed to meet the API X-70 specification. Nb- microalloyed steel is processed by the melting and casting process, and the composition is found by optical emission spectroscopy (OES). Multiple-hit deformation tests were carried out on a Gleeble® 3500 system in the standard pocket-jaw configuration to determine TNR. Cuboidal specimens (10 (L) × 20 (W) × 20 (T) mm3) were taken for compression test (multiple-hit deformation tests) in gleeble. Microstructure evolutions were carried out by using OM (optical microscopy) and SEM (scanning electron microscopy). The value of TNR determined for 0.1 wt.% niobium bearing microalloyed steel is ~ 951 °C. Nb- microalloyed steel rolled at TNR produce partially recrystallized grain with ferrite nucleation. Hence, to verify the TNR value, a rolling process is applied with the finishing rolling temperature near TNR (~951 °C). The microstructure is also revealed in the pancake shape, which confirms TNR.
    Matched MeSH terms: Alloys
  5. Al-Makramani BMA, Razak AAA, Abu-Hassan MI
    J Prosthodont, 2008 Feb;17(2):120-124.
    PMID: 18047490 DOI: 10.1111/j.1532-849X.2007.00270.x
    PURPOSE: The current study investigated the effect of different luting agents on the fracture resistance of Procera AllCeram copings.

    METHODS: Six master dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Thirty copings (Procera AllCeram) of 0.6-mm thickness were manufactured. Three types of luting media were used: zinc phosphate cement (Elite), glass ionomer cement (Fuji I), and dual-cured composite resin cement (Panavia F). Ten copings were cemented with each type. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37 degrees C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.

    RESULTS: ANOVA revealed significant differences in the load at fracture among the three groups (p < 0.001). The fracture strength results showed that the mean fracture strength of zinc phosphate cement (Elite), glass ionomer cement (Fuji I), and resin luting cement (Panavia F) were 1091.9 N, 784.8 N, and 1953.5 N, respectively.

    CONCLUSION: Different luting agents have an influence on the fracture resistance of Procera AllCeram copings.

    Matched MeSH terms: Chromium Alloys/chemistry
  6. Al-Maqtari AA, Lui JL
    J Prosthodont, 2010 Jul;19(5):347-56.
    PMID: 20456026 DOI: 10.1111/j.1532-849X.2010.00593.x
    The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging.
    Matched MeSH terms: Dental Alloys/chemistry; Metal Ceramic Alloys/chemistry*
  7. 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*
  8. Ali B, Tasirin SM, Aminayi P, Yaakob Z, Ali NT, Noori W
    Nanomaterials (Basel), 2018 Dec 14;8(12).
    PMID: 30558256 DOI: 10.3390/nano8121053
    Porous Ni, Ni-Co, Ni-Fe, and Ni-Cu magnetic alloys with a morphology similar to a giant barrel sponge were synthesized via a facile co-precipitation procedure and then by hydrogen reduction treatment. For the first time, the non-supported alloys with their unique morphology were employed in catalytic biogas decomposition (CBD) at a reaction temperature of 700 °C and 100 mL min-1 to produce syngas and carbon bio-nanofilaments, and the catalysts' behavior, CH₄ and CO₂ conversion, and the carbon produced during the reaction were investigated. All of the equimolar alloy catalysts showed good activity and stability for the catalytic biogas decomposition. The highest sustainability factor (0.66) and carbon yield (424%) were accomplished with the Ni-Co alloy without any significant inactivation for six hours, while the highest carbon efficiency of 36.43 was obtained with the Ni-Co catalyst, which is considered relatively low in comparison with industry standards, indicating a low carbon production process efficiency, possibly due to the relatively high biogas flow rate. The higher activity of the Ni-Co alloy catalyst was associated with the synergistic impact between nickel and cobalt, allowing the catalyst to maintain a high stability throughout the reaction period. Moreover, highly uniform, interwoven carbon bio-nanofilaments with a parallel and fishbone structure were achieved.
    Matched MeSH terms: Alloys
  9. Ali RM, Degenhardt R, Zambahari R, Tresukosol D, Ahmad WA, Kamar Hb, et al.
    EuroIntervention, 2011 May;7 Suppl K:K83-92.
    PMID: 22027736 DOI: 10.4244/EIJV7SKA15
    Coronary lesions in diabetics (DM) are associated with a high recurrence following percutaneous coronary intervention (PCI), even after drug-eluting stent (DES) deployment. Encouraging clinical data of the drug-eluting balloon catheter (DEB) SeQuent Please warrant its investigation in these patients.
    Matched MeSH terms: Chromium Alloys*
  10. Alp S, Baka ZM
    Am J Orthod Dentofacial Orthop, 2018 Oct;154(4):517-523.
    PMID: 30268262 DOI: 10.1016/j.ajodo.2018.01.010
    INTRODUCTION: In this study, we aimed to determine the effect of regular probiotic consumption on microbial colonization in saliva in orthodontic patients and to comparatively evaluate the difference between the systemic consumption of probiotic products and the local application.

    METHODS: This study included 3 groups with 15 orthodontic patients in each. The control group included patients who had no probiotic treatment, the subjects in the kefir group consumed 2 × 100 ml of kefir (Atatürk Orman Ciftligi, Ankara, Turkey) per day, and the subjects in the toothpaste group brushed their teeth with toothpaste with probiotic content (GD toothpaste; Dental Asia Manufacturing, Shah Alam, Selangor, Malaysia) twice a day. Samples were collected at 3 times: beginning of the study, 3 weeks later, and 6 weeks later. The salivary flow rate, buffer capacity, and Streptococcus mutans and Lactobacillus levels in the saliva were evaluated. Chair-side kits were used to determine the S mutans and Lactobacillus levels.

    RESULTS: A statistically significant decrease was observed in the salivary S mutans and Lactobacillus levels in the kefir and toothpaste groups compared with the control group (P <0.05). A statistically significant increase was observed in the toothpaste group compared with the control and kefir groups in buffer capacity. Changes in the salivary flow rate were not statistically significant.

    CONCLUSIONS: The regular use of probiotics during fixed orthodontic treatment reduces the S mutans and Lactobacillus levels in the saliva.

    Matched MeSH terms: Dental Alloys/chemistry
  11. Amjad M, Badshah S, Rafique AF, Adil Khattak M, Khan RU, Abdullah Harasani WI
    Materials (Basel), 2020 May 16;13(10).
    PMID: 32429420 DOI: 10.3390/ma13102299
    Implants are widely used in the human body for the replacement of affected bones. Fatigue failure is one of the serious concerns for implants. Therefore, understanding of the underlying mechanism leading to fatigue failure is important for the longevity of biomaterial implants. In this paper, the fracture toughness and fatigue crack growth of titanium alloy biomaterial Ti-27Nb has been experimentally investigated. The Ti-27Nb material is tested for fatigue crack growth in different environmental conditions representing the ambient and in vitro environments for 504 hours and 816 hours, respectively. Fractography of the tested specimen is conducted using Scanning Electron Microscope (SEM). The results of the fatigue crack growth propagation of the ambient and in vitro samples are similar in the Paris crack growth region. However, in the threshold region, the crack growth rate is higher for the Simulated Body Fluid (SBF) treated specimen. The fracture surface morphology of in vitro samples shows brittle fracture as compared to ambient specimens with significant plasticity and striations marks. It is proposed that a similar investigation may be conducted with specimens treated in SBF for prolonged periods to further ascertain the findings of this study.
    Matched MeSH terms: Alloys
  12. Arif, M.A.M., Omar, M.Z., Muhamad, N.
    MyJurnal
    The effect of solid solution treatment on semisolid microstructure of Zn-22Al with developed dendrites was investigated. Zn-22Al is a zinc-based alloy with aluminium as its main alloying element. Producing Zn-22Al product by semisolid metal processing (SSM) offers significant advantages, such as reduction of macrosegregations, porosity and low forming efforts. Meanwhile, thermal and microstructure analyses of Zn-22Al alloy were studied using differential scanning calorimeter (DSC) and Olympus optical microscope. Solidus and liquidus of the alloy can be determined by DSC analysis. In addition, changes to the microstructures in response to solid solution treatments were also analyzed. The major effort of all the semi-solid technologies is the generation of small and spherical morphologies. Prior to the generation of spherical morphologies, the fine grains should be first produced. The as-cast samples were isothermally held at 315°C, ranging from 0.5 to 5 hours before they were partially re-melted at semisolid temperature of 438°C to produce solid globular grains structure in liquid matrix. The results indicated that a non-dendritic semisolid microstructure could not be obtained if the traditionally cast Zn-22Al alloy with developed dendrites was directly subjected to partial remelting. After solid solution treatment at 315°C, the black interdendritic eutectics were dissolved and gradually transformed into ß structure when the treatment time was increased. The microstructure of the solid solution treated sample changed into a small globular structure with the best shape factor of 0.9 and this corresponded to 40±16µm when the sample was treated for 3 hours, followed by directly partial remelting into its semi solid zone.
    Matched MeSH terms: Alloys
  13. Aslantas K, Danish M, Hasçelik A, Mia M, Gupta M, Ginta T, et al.
    Materials (Basel), 2020 Jul 06;13(13).
    PMID: 32640567 DOI: 10.3390/ma13132998
    Micro-turning is a micro-mechanical cutting method used to produce small diameter cylindrical parts. Since the diameter of the part is usually small, it may be a little difficult to improve the surface quality by a second operation, such as grinding. Therefore, it is important to obtain the good surface finish in micro turning process using the ideal cutting parameters. Here, the multi-objective optimization of micro-turning process parameters such as cutting speed, feed rate and depth of cut were performed by response surface method (RSM). Two important machining indices, such as surface roughness and material removal rate, were simultaneously optimized in the micro-turning of a Ti6Al4V alloy. Further, the scanning electron microscope (SEM) analysis was done on the cutting tools. The overall results depict that the feed rate is the prominent factor that significantly affects the responses in micro-turning operation. Moreover, the SEM results confirmed that abrasion and crater wear mechanism were observed during the micro-turning of a Ti6Al4V alloy.
    Matched MeSH terms: Alloys
  14. Asma Alhusna Abang Abdullah, Nurul Asyikin Yahya
    Sains Malaysiana, 2011;40:1313-1317.
    Fixed orthodontic treatment requires the use of orthodontic brackets and archwires in order to correct malocclusions. The objective of this study was to evaluate the pattern of orthodontic material usages i.e. bracket and archwire among Malaysian orthodontists. A self-administered questionnaire was distributed to members of the Malaysian Association of Orthodontist. Data entry and statistical analysis was done using SPSS version 15.0. Descriptive statistics were used for analysis. Means and standard deviations were calculated for continuous variables, frequency and percentages for categorical variables. Thirty-four orthodontists responded to the survey, with 76% (n=26) were female and the mean age was 43.31 years (SD 8.76). Most respondents used conventional metal brackets (60%, n=60) and most bracket prescription used was MBT (56%, n=19). At levelling stage, most respondents used nickel titanium archwire (84.5%, n=47). Stainless steel archwire was the most favourable choice for retraction/space closure stage (73.9%, n=34). At finishing, most respondents (60.4%, n=29) preferred to use stainless steel wire in their cases. As a conclusion, specific types of orthodontic materials were preferred and used by Malaysian orthodontists in delivering orthodontic treatment.
    Matched MeSH terms: Alloys
  15. Asri RIM, Harun WSW, Samykano M, Lah NAC, Ghani SAC, Tarlochan F, et al.
    Mater Sci Eng C Mater Biol Appl, 2017 Aug 01;77:1261-1274.
    PMID: 28532004 DOI: 10.1016/j.msec.2017.04.102
    Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys. This article also takes a close look at the effect of corrosion towards the implant and human body and the mechanism to improve it. Due to this corrosion delinquent, several surface modification techniques have been used to improve the corrosion behavior of biocompatible metals such as deposition of the coating, development of passivation oxide layer and ion beam surface modification. Apart from that, surface texturing methods such as plasma spraying, chemical etching, blasting, electropolishing, and laser treatment which used to improve corrosion behavior are also discussed in detail. Introduction of surface modifications to biocompatible metals is considered as a "best solution" so far to enhanced corrosion resistance performance; besides achieving superior biocompatibility and promoting osseointegration of biocompatible metals and alloys.
    Matched MeSH terms: Alloys
  16. Baig MR, Rajan G, Yunus N
    Gerodontology, 2012 Jun;29(2):e1140-5.
    PMID: 21615782 DOI: 10.1111/j.1741-2358.2010.00433.x
    Dental rehabilitation of a completely edentulous geriatric patient has always been a challenge to the clinician, especially in treating those with higher expectations and demands. Treatment duration and the amount of residual alveolar bone available are often important considerations when planning for dental implant-based fixed treatment for these patients. With the introduction of zygomatic implants, a graftless alternative solution has emerged for deficient maxillary bone with provision for immediate loading. This article describes the treatment of a completely edentulous elderly patient using zygomatic implants in conjunction with conventional implants. The implants were immediately loaded using a definitive acrylic resin fixed denture reinforced with a cast metal framework, to provide function and aesthetics.
    Matched MeSH terms: Chromium Alloys/chemistry
  17. 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*
  18. 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
  19. 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
  20. Bakhsheshi-Rad HR, Hamzah E, Kasiri-Asgarani M, Jabbarzare S, Iqbal N, Abdul Kadir MR
    Mater Sci Eng C Mater Biol Appl, 2016 Mar;60:526-537.
    PMID: 26706560 DOI: 10.1016/j.msec.2015.11.057
    The present study addressed the synthesis of a bi-layered nanostructured fluorine-doped hydroxyapatite (nFHA)/polycaprolactone (PCL) coating on Mg-2Zn-3Ce alloy via a combination of electrodeposition (ED) and dip-coating methods. The nFHA/PCL composite coating is composed of a thick (70-80 μm) and porous layer of PCL that uniformly covered the thin nFHA film (8-10 μm) with nanoneedle-like microstructure and crystallite size of around 70-90 nm. Electrochemical measurements showed that the nFHA/PCL composite coating presented a high corrosion resistance (R(p)=2.9×10(3) kΩ cm(2)) and provided sufficient protection for a Mg substrate against galvanic corrosion. The mechanical integrity of the nFHA/PCL composite coatings immersed in SBF for 10 days showed higher compressive strength (34% higher) compared with the uncoated samples, indicating that composite coatings can delay the loss of compressive strength of the Mg alloy. The nFHA/PCL coating indicted better bonding strength (6.9 MPa) compared to PCL coating (2.2 MPa). Immersion tests showed that nFHA/PCL composite-coated alloy experienced much milder corrosion attack and more nucleation sites for apatite compared with the PCL coated and uncoated samples. The bi-layered nFHA/PCL coating can be a good alternative method for the control of corrosion degradation of biodegradable Mg alloy for implant applications.
    Matched MeSH terms: Alloys/chemistry*
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