Displaying publications 41 - 53 of 53 in total

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  1. Crestal bone loss and periimplant inflammatory parameters around zirconia implants: A systematic review
    Vohra F, Al-Kheraif AA, Ab Ghani SM, Abu Hassan MI, Alnassar T, Javed F
    J Prosthet Dent, 2015 Sep;114(3):351-7.
    PMID: 26047803 DOI: 10.1016/j.prosdent.2015.03.016
    STATEMENT OF PROBLEM: Zirconia implants have been used for oral rehabilitation; however, evidence of their ability to maintain crestal bone and periimplant soft tissue health is not clear.

    PURPOSE: The purpose of this systematic review was to evaluate crestal bone loss (CBL) around zirconia dental implants and clinical periimplant inflammatory parameters.

    MATERIAL AND METHODS: The focus question addressed was, "Do zirconia implants maintain crestal bone levels and periimplant soft tissue health?" Databases were searched for articles from 1977 through September 2014 with different combinations of the following MeSH terms: "dental implants," "zirconium," "alveolar bone loss," "periodontal attachment loss," "periodontal pocket," "periodontal index." Letters to the editor, case reports, commentaries, review articles, and articles published in languages other than English were excluded.

    RESULTS: Thirteen clinical studies were included. In 8 of the studies, the CBL around zirconia implants was comparable between baseline and follow-up. In the other 5 studies, the CBL around zirconia implants was significantly higher at follow-up. Among the studies that used titanium implants as controls, 2 studies showed significantly higher CBL around zirconia implants, and in 1 study, the CBL around zirconia and titanium implants was comparable. The reported implant survival rates for zirconia implants ranged between 67.6% and 100%. Eleven studies selectively reported the periimplant inflammatory parameters.

    CONCLUSIONS: Because of the variations in study design and methodology, it was difficult to reach a consensus regarding the efficacy of zirconia implants in maintaining crestal bone levels and periimplant soft tissue health.

    Matched MeSH terms: Zirconium*
  2. Fulltext Synthesis of waste cooking oil based biodiesel via ferric-manganese promoted molybdenum oxide / zirconia nanoparticle solid acid catalyst: influence of ferric and manganese dopants
    Alhassan FH, Rashid U, Taufiq-Yap YH
    J Oleo Sci, 2015;64(5):505-14.
    PMID: 25843280 DOI: 10.5650/jos.ess14228
    The utilization of ferric-manganese promoted molybdenum oxide/zirconia (Fe-Mn- MoO3/ZrO2) (FMMZ) solid acid catalyst for production of biodiesel was demonstrated. FMMZ is produced through impregnation reaction followed by calcination at 600°C for 3 h. The characterization of FMMZ had been done using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), transmission electron microscopy(TEM) and Brunner-Emmett-Teller (BET) surface area measurement. The effect of waste cooking oil methyl esters (WCOME's) yield on the reactions variables such as reaction temperature, catalyst loading, molar ratio of methanol/oil and reusability were also assessed. The catalyst was used to convert the waste cooking oil into corresponding methyl esters (95.6%±0.15) within 5 h at 200℃ reaction temperature, 600 rpm stirring speed, 1:25 molar ratio of oil to alcohol and 4% w/w catalyst loading. The reported catalyst was successfully recycled in six connective experiments without loss in activity. Moreover, the fuel properties of WCOME's were also reported using ASTM D 6751 methods.
    Matched MeSH terms: Zirconium/chemistry*
  3. Fulltext Effect of Nd:YAG, Er,Cr:YSGG Laser Irradiation, and Adjunctive Photodynamic Therapy on Push-Out Bond Strength of Zirconia Posts to Radicular Dentin
    Alshammary F, Karobari MI, Assiry AA, Marya A, Shaikh GM, Siddiqui AA, et al.
    Biomed Res Int, 2021;2021:5523242.
    PMID: 34036099 DOI: 10.1155/2021/5523242
    This study is aimed at assessing the influence of Nd:YAG, Er,Cr:YSGG laser irradiation, and adjunctive photodynamic therapy (aPDT) on the bond strength of zirconia posts to radicular dentin. Eighty extracted anterior teeth were randomly categorized into 4 groups (n = 20) based on varying laser irradiation treatments, i.e., conventional cleaning and shaping (CCS), Nd:YAG, Er,Cr:YSGG, and aPDT group, respectively. Using a cutting machine, the samples were prepared for push-out bond strength analysis; 4 sections (2 on each apical and cervical) of around 1 mm thickness were sectioned for all roots at a right angle to the long axis of the post. After making the space for the post, they were incorporated into the root system and were subjected to different laser treatments. The universal testing machine was utilized to assess the push-out bond strength, which had a defined 1 mm/minute crosshead speed until the failure was encountered. Specimens in the aPDT group (8.20 ± 2.14 MPa) demonstrated the highest mean push-out bond strength, whereas the lowest was shown by samples in the CCS group (7.08 ± 1.11 MPa). According to the independent t-test, the mean push-out bond strength scores of the cervical segments were higher as compared to the apical segments in research groups (p < 0.05). Overall, the adhesive type was the most frequently encountered failure mode in all of the experimental groups, with the least number of failures observed in aPDT treated teeth samples. In conclusion, the push-out bond strength to radicular dentin was not much influenced by Nd:YAG, Er,Cr:YSGG laser, and aPDT in comparison with CCS. Although statistically not significant, however, the application of aPDT provided better outcomes as compared to other research groups.
    Matched MeSH terms: Zirconium*
  4. Fulltext Effect of sandblasting, silica coating, and erbium: Yttrium-Aluminum-Garnet laser treatment on the shear bond strength of self-adhesive resin cement to alumina ceramics
    Caglar I, Ates SM, Boztoprak Y, Aslan YU, Duymus ZY
    Niger J Clin Pract, 2018 Aug;21(8):1000-1007.
    PMID: 30074001 DOI: 10.4103/njcp.njcp_300_17
    Objective: The aim of this study was to investigate the different surface treatments on the bond strength of self-adhesive resin cement to high-strength ceramic.

    Materials and Methods: Ninety aluminum oxide ceramic (Turkom-Ceramic Sdn. Bhd., Kuala Lumpur, Malaysia) specimens were produced and divided into nine groups to receive the following surface treatments: control group, no treatment (Group C), sandblasting (Group B), silica coating (Group S), erbium: yttrium-aluminum-garnet (Er:YAG) laser irradiation at 150 mJ 10 Hz (Group L1), Er:YAG laser irradiation at 300 mJ 10 Hz (Group L2), sandblasting + L1 (Group BL1), sandblasting + L2 (Group BL2), silica coating + L1 (Group SL1), and silica coating + L2 (Group SL2). After surface treatments, surface roughness (SR) values were measured and surface topography was evaluated. Resin cement was applied on the specimen surface, and shear bond strength (SBS) tests were performed. Data were statistically analyzed using one-way ANOVA and Tukey's multiple comparisons at a significance level of P < 0.05.

    Results: Group S, SL1, and SL2 showed significantly increased SR values compared to the control group (P < 0.05); therefore, no significant differences were found among the SR values of Groups B, BL1, BL2, L1, and L2 and the control group (P > 0.05). Group S showed the highest SBS values, whereas the control group showed the lowest SBS values.

    Conclusion: Silica coating is the most effective method for resin bonding of high strength ceramic, but Er:YAG laser application decreased the effectiveness.

    Matched MeSH terms: Zirconium/chemistry*
  5. Enhancement of thermal, mechanical and physical properties of polyamide 12 composites via hybridization of ceramics for bone replacement
    Abdullah AM, Mohamad D, Rahim TNAT, Akil HM, Rajion ZA
    Mater Sci Eng C Mater Biol Appl, 2019 Jun;99:719-725.
    PMID: 30889745 DOI: 10.1016/j.msec.2019.02.007
    This study reports the influence of ZrO2/β-TCP hybridization on the thermal, mechanical, and physical properties of polyamide 12 composites to be suited for bone replacement. Amount of 15 wt% of nano-ZrO2 along with 5,10,15,20 and 25 wt% of micro-β-TCP was compounded with polyamide 12 via a twin-screw extruder. The hybrid ZrO2/β-TCP filled polyamide 12 exhibited higher thermal, mechanical and physical properties in comparison to unfilled polyamide 12 at certain filler loading; which is attributed to the homogenous dispersion of ZrO2/β-TCP fillers particle in polyamide 12 matrix. The hybrid ZrO2/β-TCP filled PA 12 demonstrated an increment of tensile strength by up to 1%, tensile modulus of 38%, flexural strength of 15%, flexural modulus of 45%, and surface roughness value of 93%, as compared to unfilled PA 12. With enhanced thermal, mechanical and physical properties, the newly developed hybrid ZrO2/β-TCP filled PA 12 could be potentially utilized for bone replacement.
    Matched MeSH terms: Zirconium/chemistry
  6. Fulltext Finite Element Analysis of Single Cell Stiffness Measurements Using PZT-Integrated Buckling Nanoneedles
    Rad MA, Tijjani AS, Ahmad MR, Auwal SM
    Sensors (Basel), 2016 Dec 23;17(1).
    PMID: 28025571 DOI: 10.3390/s17010014
    This paper proposes a new technique for real-time single cell stiffness measurement using lead zirconate titanate (PZT)-integrated buckling nanoneedles. The PZT and the buckling part of the nanoneedle have been modelled and validated using the ABAQUS software. The two parts are integrated together to function as a single unit. After calibration, the stiffness, Young's modulus, Poisson's ratio and sensitivity of the PZT-integrated buckling nanoneedle have been determined to be 0.7100 N·m-1, 123.4700 GPa, 0.3000 and 0.0693 V·m·N-1, respectively. Three Saccharomyces cerevisiae cells have been modelled and validated based on compression tests. The average global stiffness and Young's modulus of the cells are determined to be 10.8867 ± 0.0094 N·m-1 and 110.7033 ± 0.0081 MPa, respectively. The nanoneedle and the cell have been assembled to measure the local stiffness of the single Saccharomyces cerevisiae cells The local stiffness, Young's modulus and PZT output voltage of the three different size Saccharomyces cerevisiae have been determined at different environmental conditions. We investigated that, at low temperature the stiffness value is low to adapt to the change in the environmental condition. As a result, Saccharomyces cerevisiae becomes vulnerable to viral and bacterial attacks. Therefore, the proposed technique will serve as a quick and accurate process to diagnose diseases at early stage in a cell for effective treatment.
    Matched MeSH terms: Zirconium/chemistry*
  7. Fulltext Polymerization Shrinkage and Degree of Conversion of New Zirconia-Reinforced Rice Husk Nanohybrid Composite
    Lin GSS, Abdul Ghani NRN, Ismail NH, Singbal KP, Yusuff NMM
    Eur J Dent, 2020 Jul;14(3):448-455.
    PMID: 32599624 DOI: 10.1055/s-0040-1713951
    OBJECTIVES:  This study aimed to compare the polymerization shrinkage and degree of conversion of new zirconia-reinforced rice husk nanohybrid composite with commercialized microhybrid and nanofilled composites.

    MATERIALS AND METHODS:  Overall, 180 samples were used for polymerization shrinkage (buoyancy and optical methods) and degree of conversion tests in which they were divided into Group 1, nanofilled composite (Filtek-Z350- XT; 3M ESPE, St Paul, MN 55144-1000, USA), Group 2, microhybrid composite (Zmack-Comp), and Group 3, nanohybrid composite (Zr-Hybrid). Polymerization shrinkage test was performed using buoyancy and optical methods. For buoyancy method, samples were weighed in air and water to calculate the shrinkage value, whereas, for optical method, images of nonpolymerized samples were captured under a digital microscope and recaptured again after light-cured to calculate the percentage of shrinkage. Degree of conversion was tested using Fourier-transform infrared spectroscopy spectrometer.

    STATISTICAL ANALYSIS:  Data were analyzed using one-way analysis of variance complemented by post hoc Dunnett's T3 test for polymerization shrinkage and Tukey's honestly significant difference test for degree of conversion. Level of significance was set at p < 0.05.

    RESULTS:  Group 3 demonstrated similar polymerization shrinkage with Group 1, but lower shrinkage (p < 0.05) than Group 2 based on buoyancy method. However, optical method (p < 0.05) showed that Group 3 had the lowest shrinkage, followed by Group 1 and lastly Group 2. Besides, Group 3 showed a significantly higher degree of conversion (p < 0.05) than Group 1 and comparable conversion value with Group 2.

    CONCLUSIONS:  Zirconia-reinforced rice husk nanohybrid composite showed excellent shrinkage and conversion values, hence can be considered as an alternative to commercially available composite resins.

    Matched MeSH terms: Zirconium
  8. Fulltext Environmental radiological monitoring methods in tenorm facilities and its relevance
    Teng, Iyu Lin, Ismail Bahari, Muhamad Samudi Yasir
    Journal of Nuclear and Related Technologies, 2011;2011(2):8-14.
    MyJurnal
    In Malaysia, mineral processing plant is one of the Naturally Occurring Radioactive Material (NORM) processing industries controlled by the Atomic Energy Licensing Board (AELB) through the enforcement of Atomic Energy Licensing Act 1984 (Act 304). The activities generated waste which is called as TENORM wastes. TENORM wastes are mainly found in thorium hydroxide from the processing of xenotime and monazite, and iron oxide and red gypsum from the processing of ilmenite. Other TENORM wastes are scales and sludge from the oil and gas industries, tin slag produced from the smelting of tin, and ilmenite, zircon,
    and monazite produced from the processing of tin tailing (amang). The environmental and radiological monitoring program is needed to ensure that the TENORM wastes did not caused any contamination to the environment. The wastes vary in the types of samples, parameters of analysis as well as the frequency of monitoring based on license’s conditions issued by the AELB. The main objective of this study is to assess the suitability of license’s condition and the monitoring program required in oil and gas, and mineral processing
    industries. Study was done by assessing the data submitted to the AELB in order to comply with the licensing requirement. This study had found out that there are a few of license’s conditions that need to be reviewed accordingly based on the processing activity.
    Matched MeSH terms: Zirconium
  9. Fulltext Free standing zirconia nanotubes formation and their photocatalytic properties
    Syahriza Ismail, Nurul Izza Soaid, Suriyati Mohamed Ansari, Nurulhuda Bashirom, Monna Rozana, Tan, Wai Kian, et al.
    Malaysian Journal of Microscopy, 2016;12(1):20-23.
    MyJurnal
    In the formation of ZrO2 (zirconia) nanotubes (ZNTs) by anodisation of zirconium, a balance between chemical etching at the surface of the nanotubes and inward growth inside the nanotubes is required. This can be achieved by using fluorinated organic electrolyte like ethylene glycol with the addition of small volume of oxidant. In this work, carbonate was selected as the oxidant and NH4F as the source of fluoride for chemical etching process. Two sets of electrolytes were studied EG/fluoride/Na2CO3 and EG/fluoride/K2CO3. It appears that in the presence of carbonate evolution of gas at the anode during the anodisation process was rather severe. The gas which is likely to be CO2 was found to weaken the adherence between the oxide film with the underlying Zr foil. This induced the formation of free standing ZNTs. High Resolution Transmission Electron Microscope (HRTEM) was used to investigate the crystallinity of the nanotubes where the majority crystal phase of ZNTs was tetragonal/cubic. The ZNTs were used as photocatalysts to oxidize methyl orange dye.
    Matched MeSH terms: Zirconium
  10. Effective adsorption of cadmium and lead using SO3H-functionalized Zr-MOFs in aqueous medium
    Gul S, Ahmad Z, Asma M, Ahmad M, Rehan K, Munir M, et al.
    Chemosphere, 2022 Nov;307(Pt 1):135633.
    PMID: 35810866 DOI: 10.1016/j.chemosphere.2022.135633
    Cadmium (Cd) and Lead (Pb) from industrial wastewater can bioaccumulate in the living organisms of water bodies, posing serious threats to human health. Therefore, efficient remediation of heavy metal ions of Cd (II) and Pb (II) in aqueous media is necessary for public health and environmental sustainability. In the present study, water stable Zirconium (Zr) based metal organic frameworks (MOFs) with SO3H functionalization were synthesized by solvothermal method and used first time for the adsorption of Cd (II) and Pb (II). Synthesis of UiO-66-SO3H, nano-sized (<100 nm) MOFs, was confirmed by FTIR, XRD, FESEM and BET. Effects of contact time, pH and temperature were investigated for adsorption of Cd (II) and Pb (II) onto SO3H-functionalized Zr-MOFs. The UiO-66-SO3H displayed notable rejections of 97% and 88% towards Cd (II) and Pb (II), respectively, after 160 min at 25 °C and pH (6) with an initial concentration of 1000 mg/L. Adsorption capacities of Cd (II) and Pb (II) were achieved as 194.9154 (mg/g) and 176.6879 (mg/g), respectively, at an initial concentration of 1000 mg/L. The Pseudo second-order kinetic model fitted well with linear regression (R2) of value 1. The mechanism was confirmed mainly as a chemisorption and coordination interaction between sulfone group (-SO3H) and metal ions Cd (IIa) and Pb (II). These results may support effective adsorption and can be studied further to enrich and recycle other heavy metals from wastewater.
    Matched MeSH terms: Zirconium
  11. Fabrication and mechanical properties of Al2O3/SiC/ZrO2 functionally graded material by electrophoretic deposition
    Askari E, Mehrali M, Metselaar IH, Kadri NA, Rahman MM
    J Mech Behav Biomed Mater, 2012 Aug;12:144-50.
    PMID: 22732480 DOI: 10.1016/j.jmbbm.2012.02.029
    This study describes the synthesis of Al(2)O(3)/SiC/ZrO(2) functionally graded material (FGM) in bio-implants (artificial joints) by electrophoretic deposition (EPD). A suitable suspension that was based on 2-butanone was applied for the EPD of Al(2)O(3)/SiC/ZrO(2), and a pressureless sintering process was applied as a presintering. Hot isostatic pressing (HIP) was used to densify the deposit, with beneficial mechanical properties after 2 h at 1800 °C in Ar atmosphere. The maximum hardness in the outer layer (90 vol.% Al(2)O(3)+10 vol.% SiC) and maximum fracture toughness in the core layer (75 vol.% Al(2)O(3)+10 vol.% SiC + 15 vol.% ZrO(2)) composite were 20.8±0.3 GPa and 8±0.1 MPa m(1/2), respectively. The results, when compared with results from Al(2)O(3)/ZrO(2) FGM, showed that SiC increased the compressive stresses in the outer layers, while the inner layers were under a residual tensile stress.
    Matched MeSH terms: Zirconium/chemistry*
  12. Evaluation of the marginal fit of a zirconia ceramic computer-aided machined (CAM) crown system
    Baig MR, Tan KB, Nicholls JI
    J Prosthet Dent, 2010 Oct;104(4):216-27.
    PMID: 20875526 DOI: 10.1016/S0022-3913(10)60128-X
    The marginal fit of crowns is a concern for clinicians, and there is no conclusive evidence of any one margin configuration yielding better results than others in terms of marginal fit.
    Matched MeSH terms: Zirconium
  13. Catalytic performance of Cu/ZnO/Al2O3/ZrO2 for slurry methanol synthesis from CO2 Hydrogenation: Effect of Cu/Zn Molar Ratio
    Salina Shaharun, Maizatul S. Shaharun, Mohamad F.M. Shah, Nurul A. Amer
    Sains Malaysiana, 2018;47:207-214.
    Catalytic hydrogenation of carbon dioxide (CO2) to methanol is an attractive way to recycle and utilize CO2. A series of Cu/ZnO/Al2O3/ZrO2 catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive x-ray analysis (FESEM-EDX) and X-ray diffraction (XRD). Higher surface area, SABET values (42.6-59.9 m2/g) were recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m2/g was found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 93.9 was achieved at Cu/Zn molar ratio of 0.33. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 6.4%.
    Matched MeSH terms: Zirconium
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