Displaying publications 121 - 140 of 227 in total

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  1. Fulltext In-vitro performance of posterior fiber reinforced composite (FRC) bridge with different framework designs
    Ang Y, Tan CG, Yahaya N
    Dent Mater J, 2021 May 29;40(3):584-591.
    PMID: 33328396 DOI: 10.4012/dmj.2020-213
    This study aimed to investigate the effect of various framework designs on the failure of posterior fiber reinforced composite (FRC) bridges and assess the post crack performances of the repaired prostheses. Thirty samples were prepared into three different groups of framework designs: cuspal support (CS), anatomic features (AF) and circular reinforcement (CR). All specimens were subjected to static loading test and acoustic emission analysis. Significant differences were found in the load and time of initial failures among the three groups (p<0.001). CS was identified as the optimum framework design. Samples with composite delamination at the pontic site were selected and repaired with a clinically simplified protocol. Significant differences were also observed between the repaired and original FRC bridges (p=0.01). The performance of these prostheses was highly dependent on the framework design and the perspective of repairing FRC bridges may warrant future investigations.
    Matched MeSH terms: Glass
  2. Fulltext The flexural strengths of five commercially available tooth-coloured restorative materials
    Sulaiman, E., Yeo, Y.M., Chong, Y.T.
    Ann Dent, 2007;14(1):39-45.
    MyJurnal
    Purpose of the study: The objective of this study was to investigate the flexural strengths of five commercially available tooth-coloured restorative materials – Alpha-Dent (composite resin, Dental Technologies Inc.), Solare Anterior (composite resin, GC), F2000 (polyacid-modified composite resin, 3M), Beautifil (giomer, Shofu) and Fuji II LC (resin- modified glass ionomer cement, GC] using the ISO 4049 specifications. Materials and Method: Ten specimens of (25±0.2)mm x (2±0.1)mm x (2±0.1)mm from each material were prepared at 22-23ºC using a customized metal mould. After light polymerization, the specimens were stored in distilled water at 37ºC for 24 hours. The specimens were subsequently blotted dry, measured and subjected to flexural testing using an Instron Universal Testing Machine with a crosshead speed of 0.5mm/min. The flexural strengths were calculated from the maximum load exerted on the specimens. Data were analysed using one way ANOVA and scheffe’s post-hoc multiple comparison tests at a significance level of 0.05.Results: The results showed that the mean flexural strengths of Beautifil, Solare Anterior and Alpha-Dent were above 80 MPa and those of F2000 and Fuji II LC were below 80 MPa. The results of one-way ANOVA and Scheffe’s post-host tests demonstrated that Beautifil had significantly higher mean flexural strength compared to Fuji II LC, F2000 and Alpha-Dent (P
    Matched MeSH terms: Glass Ionomer Cements
  3. Fulltext Assessment of microleakage of few restorative materials after erosion by acidic solution
    Suhaida Sabdi, Wan Zaripah Wan Bakar, Adam Husein
    Archives of Orofacial Sciences, 2011;6(2):26-32.
    MyJurnal
    Some restorative materials are susceptible to erosion but whether it also causes microleakage is still questionable. The aim of this study was to assess the microleakage of few restorative materials after immersion in acidic solution. Standardized ‘U’ shaped cavity of 4mm diameter and 2mm depth were prepared on buccal or lingual surface of 52 human premolar and molar teeth. The teeth were divided into 4 groups which contains 13 samples and 3 controls for each and were restored either with Filtek Z250 (Group 1), Fuji IX (Group 2), Fuji II LC (Group 3), or Silverfill amalgam (Group 4).
    All surfaces were painted with nail varnish leaving only 2mm of tooth structure surrounding the restoration before the study samples were immersed in acidic solution, lemon juice (pH 2.74) and control samples in deionised distilled water for 24 hours. Surface photos for erosion were taken before immersion in methylene blue for 7 days. After sectioning, the assessment of dye penetration was done using Leica Imaging System DMLM (Germany). Photos showed that Fuji IX demonstrated severe erosion but no obvious changes were seen on other materials. Kruskal-Wallis test indicated that microleakage between all four groups were statistically significant. The most significant difference was between Filtek Z250 and Fuji IX (p
    Matched MeSH terms: Glass Ionomer Cements
  4. Fulltext A study on the effects of environment on curing characteristics of thixotropic and room temperature cured epoxy-based adhesives using DMTA
    Ahmad, Z., Rohana, H., Md Tahir, P.
    ASM Science Journal, 2013;7(1):37-58.
    MyJurnal
    This study investigated the thermal properties of three room temperature curing adhesives containing nano particles which were thixotropic and shear thinning which allowed injection into overhead holes when exposed to different environmental conditions. Viscosity and shear stress of the adhesives were measured as a function of shear rate. The thermal behaviour of the adhesives were measured using dynamic mechanical thermal anylisis following exposures to different temperatures and humidities which included temperatures of 20 degrees Celcius, 30 degrees Celcius and 50 degrees Celcius, relative humidities of 65% RH, 75% RH 95% RH soaked in water at 20 degrees Celcius and placed in the oven at 50 degrees Celcius. The dynamic thermal properties reported include storage and loss modulus, the loss tangent and the glass transition temperature ( Tg ). For nano- and micro-particles filled adhesives, the Tg increased with the temperature increase, even though the adhesives was subjected to high humidity and this was due to further cross-linking. The results showed that room temperature cured epoxies were only partially cured at room temperature.
    Matched MeSH terms: Glass
  5. Sputtered Encapsulation as Wafer Level Packaging for Isolatable MEMS Devices: A Technique Demonstrated on a Capacitive Accelerometer
    Hamzah AA, Yunas J, Majlis BY, Ahmad I
    Sensors (Basel), 2008 Nov 19;8(11):7438-7452.
    PMID: 27873938
    This paper discusses sputtered silicon encapsulation as a wafer level packaging approach for isolatable MEMS devices. Devices such as accelerometers, RF switches, inductors, and filters that do not require interaction with the surroundings to function, could thus be fully encapsulated at the wafer level after fabrication. A MEMSTech 50g capacitive accelerometer was used to demonstrate a sputtered encapsulation technique. Encapsulation with a very uniform surface profile was achieved using spin-on glass (SOG) as a sacrificial layer, SU-8 as base layer, RF sputtered silicon as main structural layer, eutectic gold-silicon as seal layer, and liquid crystal polymer (LCP) as outer encapsulant layer. SEM inspection and capacitance test indicated that the movable elements were released after encapsulation. Nanoindentation test confirmed that the encapsulated device is sufficiently robust to withstand a transfer molding process. Thus, an encapsulation technique that is robust, CMOS compatible, and economical has been successfully developed for packaging isolatable MEMS devices at the wafer level.
    Matched MeSH terms: Glass
  6. Fulltext Physical and Clinical Evaluation of Hip Spica Cast applied with Three-slab Technique using Fibreglass Material
    Bitar KM, Ferdhany ME, Ashraf EI, Saw A
    Malays Orthop J, 2016 Nov;10(3):17-20.
    PMID: 28553442 MyJurnal DOI: 10.5704/MOJ.1611.008
    Introduction: Hip spica casting is an important component of treatment for developmental dysplasia of the hip (DDH) and popular treatment method for femur fractures in children. Breakage at the hip region is a relatively common problem of this cast. We have developed a three-slab technique of hip spica application using fibreglass as the cast material. The purpose of this review was to evaluate the physical durability of the spica cast and skin complications with its use. Methodology: A retrospective review of children with various conditions requiring hip spica immobilisation which was applied using our method. Study duration was from 1st of January 2014 until 31st December 2015. Our main outcomes were cast breakage and skin complications. For children with hip instability, the first cast would be changed after one month, and the second cast about two months later. Results: Twenty-one children were included, with an average age of 2.2 years. The most common indication for spica immobilisation was developmental dysplasia of the hip. One child had skin irritation after spica application. No spica breakage was noted. Conclusion: This study showed that the three-slab method of hip spica cast application using fibreglass material was durable and safe with low risk of skin complications.
    Matched MeSH terms: Glass
  7. Fulltext Image Analysis of Surface Porosity Mortar Containing Processed Spent Bleaching Earth
    Wei Chong B, Othman R, Jaya RP, Shu Ing D, Li X, Wan Ibrahim MH, et al.
    Materials (Basel), 2021 Mar 28;14(7).
    PMID: 33800634 DOI: 10.3390/ma14071658
    Image analysis techniques are gaining popularity in the studies of civil engineering materials. However, the current established image analysis methods often require advanced machinery and strict image acquisition procedures which may be challenging in actual construction practices. In this study, we develop a simplified image analysis technique that uses images with only a digital camera and does not have a strict image acquisition regime. Mortar with 10%, 20%, 30%, and 40% pozzolanic material as cement replacement are prepared for the study. The properties of mortar are evaluated with flow table test, compressive strength test, water absorption test, and surface porosity based on the proposed image analysis technique. The experimental results show that mortar specimens with 20% processed spent bleaching earth (PSBE) achieve the highest 28-day compressive strength and lowest water absorption. The quantified image analysis results show accurate representation of mortar quality with 20% PSBE mortar having the lowest porosity. The regression analysis found strong correlations between all experimental data and the compressive strength. Hence, the developed technique is verified to be feasible as supplementary mortar properties for the study of mortar with pozzolanic material.
    Matched MeSH terms: Glass Ionomer Cements
  8. Fulltext Thermal Delamination Modelling and Evaluation of Aluminium-Glass Fibre-Reinforced Polymer Hybrid
    Chow ZP, Ahmad Z, Wong KJ, Koloor SSR, Petrů M
    Polymers (Basel), 2021 Feb 04;13(4).
    PMID: 33557350 DOI: 10.3390/polym13040492
    This paper aims to propose a temperature-dependent cohesive model to predict the delamination of dissimilar metal-composite material hybrid under Mode-I and Mode-II delamination. Commercial nonlinear finite element (FE) code LS-DYNA was used to simulate the material and cohesive model of hybrid aluminium-glass fibre-reinforced polymer (GFRP) laminate. For an accurate representation of the Mode-I and Mode-II delamination between aluminium and GFRP laminates, cohesive zone modelling with bilinear traction separation law was implemented. Cohesive zone properties at different temperatures were obtained by applying trends of experimental results from double cantilever beam and end notched flexural tests. Results from experimental tests were compared with simulation results at 30, 70 and 110 °C to verify the validity of the model. Mode-I and Mode-II FE models compared to experimental tests show a good correlation of 5.73% and 7.26% discrepancy, respectively. Crack front stress distribution at 30 °C is characterised by a smooth gradual decrease in Mode-I stress from the centre to the edge of the specimen. At 70 °C, the entire crack front reaches the maximum Mode-I stress with the exception of much lower stress build-up at the specimen's edge. On the other hand, the Mode-II stress increases progressively from the centre to the edge at 30 °C. At 70 °C, uniform low stress is built up along the crack front with the exception of significantly higher stress concentrated only at the free edge. At 110 °C, the stress distribution for both modes transforms back to the similar profile, as observed in the 30 °C case.
    Matched MeSH terms: Glass
  9. Sustainable mixed matrix membranes containing porphyrin and polysulfone polymer for acid gas separations
    Saqib S, Rafiq S, Muhammad N, Khan AL, Mukhtar A, Ullah S, et al.
    J Hazard Mater, 2021 06 05;411:125155.
    PMID: 33858108 DOI: 10.1016/j.jhazmat.2021.125155
    The synergetic effect of nitrogen-rich and CO2-philic filler and polymer in mixed matrix-based membranes (MMMs) can separate CO2 competently. The introduction of well-defined nanostructured porous fillers of pores close to the kinetic diameter of the gas molecule and polymer matrix compatibility is a challenge in improving the gas transportation characteristics of MMMs. This study deals with the preparation of porphyrin filler and the polysulfone (PSf) polymer MMMs. The fillers demonstrated uniform distribution, uniformity, and successful bond formation. MMMs demonstrated high thermal stability with a glass transition temperature in the range of 480-610 °C. The porphyrin filler exhibited microporous nature with the presence of π-π bonds and Lewis's basic functionalities between filler-polymer resulted in a highly CO2-philic structure. The pure and mixed gas permeabilities and selectivity were successfully improved and surpass the Robeson's upper bound curve's tradeoff. Additionally, the temperature influence on CO2 permeability revealed lower activation energies at higher temperatures leading to the gas transport facilitation. This can be granted consistency and long-term durability in polymer chains. These results highlight the unique properties of porphyrin fillers in CO2 separation mixed matrix membranes and offer new knowledge to increase comprehension of PSf performance under various contents or environments.
    Matched MeSH terms: Glass
  10. Fulltext Fabrication and Characterization of High-Quality UV Photodetectors Based ZnO Nanorods Using Traditional and Modified Chemical Bath Deposition Methods
    Abdulrahman AF, Ahmed SM, Barzinjy AA, Hamad SM, Ahmed NM, Almessiere MA
    Nanomaterials (Basel), 2021 Mar 09;11(3).
    PMID: 33803274 DOI: 10.3390/nano11030677
    Ultraviolet (UV) photodetectors (PDs) based on high-quality well-aligned ZnO nanorods (NRs) were fabricated using both modified and conventional chemical bath deposition (CBD) methods. The modified chemical bath deposition (M-CBD) method was made by adding air bubbles to the growth solution during the CBD process. The viability and effectiveness of M-CBD were examined by developing UV PDs based on ZnO NRs. The ZnO nano-seed layer was coated on a glass substrate utilizing radiofrequency (RF) sputtering. The impact of the different growth-times on morphology, growth rate, crystal structure, and optical and chemical properties were investigated systematically using different characterization techniques, such as field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) analysis, UV-VIS double beam spectrometer, and energy dispersive X-ray analysis (EDX), respectively. The Al/ZnO UV PDs based on ZnO nanorods were fabricated with optimum growth conditions through the two methods of preparation. This study showed that the synthesized ZnO NRs using the M-CBD method for different growth times possess better properties than the conventional method under similar deposition conditions. Despite having the highest aspect ratio and growth rate of ZnO NRs, which were found at 4 h growth duration for both methods, the aspect ratio of ZnO NRs using the M-CBD technique was comparatively higher than the conventional CBD method. Besides, the UV PDs fabricated by the M-CBD method at 5 V bias voltage showed high sensitivity, short response time, quick recovery time, high gain, low dark current, and high photocurrent compared with the UV PD device fabricated by the conventional CBD method.
    Matched MeSH terms: Glass
  11. Effect of Wear Conditions, Parameters and Sliding Motions on Tribological Characteristics of Basalt and Glass Fibre Reinforced Epoxy Composites
    Talib AAA, Jumahat A, Jawaid M, Sapiai N, Leao AL
    Materials (Basel), 2021 Feb 02;14(3).
    PMID: 33540915 DOI: 10.3390/ma14030701
    Basalt fibre is a promising mineral fibre that has high potential to replace synthetic based glass fibre in today's stringent environmental concern. In this study, friction and wear characteristics of glass and basalt fibres reinforced epoxy composites were studied and comparatively evaluated at two test stages. The first stage was conducted at fixed load, speed and distance under three different conditions; adhesive, abrasive and erosive wear, wherein each composite specimens slide against steel, silicon carbide, and sand mixtures, respectively. The second stage was conducted involving different types of adhesive sliding motions against steel counterpart; unidirectional and reciprocating motion, with the former varied at pressure-velocity (PV) factor; 0.23 MPa·m/s and 0.93 MPa·m/s, while the latter varied at counterpart's configuration; ball-on-flat (B-O-F) and cylinder-on-flat (C-O-F). It was found that friction and wear properties of composites are highly dependent on test conditions. Under 10 km test run, Basalt fibre reinforced polymer (BFRP) composite has better wear resistance against erosive sand compared to Glass fibre reinforced polymer (GFRP) composite. In second stage, BFRP composite showed better wear performance than GFRP composite under high PV of unidirectional sliding test and under B-O-F configuration of reciprocating sliding test. BFRP composite also exhibited better friction properties than GFRP composite under C-O-F configuration, although its specific wear rate was lower. In scanning electron microscopy examination, different types of wear mechanisms were revealed in each of the test conducted.
    Matched MeSH terms: Glass
  12. Investigation of indentation size effect and R-curve behaviour of Li2O-SiO2 and Li2O-2SiO2 glass ceramics
    Alao AR, Mohd Azhari MA
    J Mech Behav Biomed Mater, 2021 12;124:104842.
    PMID: 34555624 DOI: 10.1016/j.jmbbm.2021.104842
    Indentation size effect (ISE) and R-curve behaviour of Li2O-SiO2 and Li2O-2SiO2 glass ceramics are investigated using micro-indentation and indentation-strength (IS) techniques, respectively. Vickers micro-indentations were applied on both materials at the load of 0.10-19.6 N to determine the load influence on the measured hardness. For the IS-measured fracture toughness, the load ranged from 1.96 to 19.6 N. The hardness decreased with increasing load by 20% and 18% on Li2O-SiO2 and Li2O-2SiO2 glass ceramics, respectively, indicating the ISE behaviour on both materials. The fracture toughness increased with the load by 27% and 59% on Li2O-SiO2 and Li2O-2SiO2 glass ceramics, respectively, signifying the R-curve behaviour. The ISE behaviour of both materials was analysed using the Meyer's, Hays-Kendall (HK), proportional specimen resistance (PSR), Nix-Gao (NG), modified PSR (MPSR) and elastic plastic deformation (EPD) models while the R-curve behaviour was analysed by the fractional power law. The Meyer's index of both materials was less than 2, strongly confirming the ISE existence. The HK, PSR and NG models were only suitable to determine intrinsic Vickers hardness for Li2O-2SiO2 glass ceramic while the MPSR and EPD models were successful for both materials. The fractional power law gave higher R-curve steepness for Li2O-2SiO2 than Li2O-SiO2 glass ceramics. Also, material and brittleness indices predicted, respectively, higher quasi-plasticity and better machinability for Li2O-2SiO2 than Li2O-SiO2 glass ceramics indicating superior performance in the former to the latter. Finally, this study presents a new significant insight into the micro-mechanisms of fracture tolerance behaviour of these glass ceramics which is critical to their functional performance as structural ceramics.
    Matched MeSH terms: Glass
  13. Fulltext STRENGTH AND DURABILITY OF KENAFFIBER REINFORCED CONCRETE FOR MARINE STRUCTURES
    NUR FIKRIAH HASHIM, NURAQILAH MOHD ZAINAL, NURAIN JAMIL, NURUL NASUHA MOHD NOR, SURIANI MAT JUSOH
    UMT Journal of Undergraduate Research, 2019;1(1):113-118.
    MyJurnal
    Nowadays, Kenaf fiber is sustainably useful in marine structures and has become one of the materials that may be high in demand as it is light, biodegradable and environmental friendly. This study investigates the effect of fiber percentage on compressive strength of fiber reinforced concrete (FRC) and the relationship between compressive strength and time of FRC immersion in seawater. FRC concrete cubes were prepared using four different percentage of fiber (0%, 1.5%, 3.0% and 4.5%). These FRC were immersed in seawater for 7, 14 and 21 days for three consecutive weeks. Based on the experiment, it was found that there was improvement in compressive strength of FRC when compared to plain cement concrete. The results showedthat 3.0% of KF to cement matrix concrete determined the highest compressive strength of 205.43 Pa while 0% of KF fiber to cement concrete matrix (control specimen) showed the lowest compressive strength of 158.28 Pa. Also the addition of Kenaf fiber to cement concrete decreased the seawater absorption more than concrete with absolutely 0% of KF fiber to cement concrete (control specimen). In conclusion, the results did show significant improvement and a consistent trend on strength with the addition of FRC. This study also revealed that the percentage of water absorption was on the increase for 0, 7 and 14 days and become constant after day 21. This is due to manufacturing defects that occurred which block the water from entering the material and making the material absorb less water.
    Matched MeSH terms: Glass Ionomer Cements
  14. Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides
    Hashim S, Alajerami YS, Ramli AT, Ghoshal SK, Saleh MA, Abdul Kadir AB, et al.
    Appl Radiat Isot, 2014 Sep;91:126-30.
    PMID: 24929526 DOI: 10.1016/j.apradiso.2014.05.023
    Lithium potassium borate (LKB) glasses co-doped with TiO2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of (60)Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230 °C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Z(eff)=8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10(3) Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software.
    Matched MeSH terms: Glass
  15. Synthesis and characterization of YBa2Cu3O7(Y123) via sol-gel method for development of superconducting quantum interference device magnetometer
    Yahya N, Zakariah MH
    J Nanosci Nanotechnol, 2012 Oct;12(10):8147-52.
    PMID: 23421192
    Electromagnetic (EM) waves transmitted by Horizontal Electric Dipole (HED) source to detect contrasts in subsurface resistivity termed Seabed Logging (SBL) is now an established method for hydrocarbon exploration. However, currently used EM wave detectors for SBL have several challenges including the sensitivity and its bulk size. This work exploits the benefit of superconductor technology in developing a magnetometer termed Superconducting Quantum Interference Device (SQUID) which can potentially be used for SBL. A SQUID magnetometer was fabricated using hexagon shape-niobium wire with YBa2Cu37O, (YBCO) as a barrier. The YBa2Cu37O, samples were synthesized by sol-gel method and were sintered using a furnace and conventional microwave oven. The YBCO gel was dried at 120 degrees C in air for 72 hours. It was then ground and divided into 12 parts. Four samples were sintered at 750 degrees C, 850 degrees C, 900 degrees C, and 950 degrees C for 12 hours in a furnace to find the optimum temperature. The other eight samples were sintered in a microwave with 1100 Watt (W) with a different sintering time, 5, 15, 45 minutes, 1 hour, 1 hour 15 minutes, 1 hour 30 minutes, 1 hour 45 minutes and 2 hours. A DEWAR container was designed and fabricated using fiberglass material. It was filled with liquid nitrogen (LN2) to ensure the superconducting state of the magnetometer. XRD results showed that the optimum sintering temperature for the formation of orthorhombic Y-123 phase was at 950 degrees C with the crystallite size of 67 nm. The morphology results from Field Emission Scanning Electron Microscopy (FESEM) showed that the grains had formed a rod shape with an average diameter of 60 nm. The fabricated SQUID magnetometer was able to show an increment of approximately 249% in the intensity of the EM waves when the source receiver offset was one meter apart.
    Matched MeSH terms: Glass
  16. Fulltext Stochasticity of bacterial attachment and its predictability by the extended derjaguin-landau-verwey-overbeek theory
    Chia TW, Nguyen VT, McMeekin T, Fegan N, Dykes GA
    Appl Environ Microbiol, 2011 Jun;77(11):3757-64.
    PMID: 21478319 DOI: 10.1128/AEM.01415-10
    Bacterial attachment onto materials has been suggested to be stochastic by some authors but nonstochastic and based on surface properties by others. We investigated this by attaching pairwise combinations of two Salmonella enterica serovar Sofia (S. Sofia) strains (with different physicochemical and attachment properties) with one strain each of S. enterica serovar Typhimurium, S. enterica serovar Infantis, or S. enterica serovar Virchow (all with similar physicochemical and attachment abilities) in ratios of 0.428, 1, and 2.333 onto glass, stainless steel, Teflon, and polysulfone. Attached bacterial cells were recovered and counted. If the ratio of attached cells of each Salmonella serovar pair recovered was the same as the initial inoculum ratio, the attachment process was deemed stochastic. Experimental outcomes from the study were compared to those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Significant differences (P < 0.05) between the initial and the attached ratios for serovar pairs containing S. Sofia S1296a for all different ratios were apparent for all materials. For S. Sofia S1635-containing pairs, 7 out of 12 combinations of serovar pairs and materials had attachment ratios not significantly different (P > 0.05) from the initial ratio of 0.428. Five out of 12 and 10 out of 12 samples had attachment ratios not significantly different (P > 0.05) from the initial ratios of 1 and 2.333, respectively. These results demonstrate that bacterial attachment to different materials is likely to be nonstochastic only when the key physicochemical properties of the bacteria were significantly different (P < 0.05) from each other. XDLVO theory could successfully predict the attachment of some individual isolates to particular materials but could not be used to predict the likelihood of stochasticity in pairwise attachment experiments.
    Matched MeSH terms: Glass
  17. Fulltext Physical properties and cytotoxicity comparison of experimental gypsum-based biomaterials with two current dental cement materials on L929 fibroblast cells
    Mahshim N, Reza F, Omar NS
    J Conserv Dent, 2013 Jul;16(4):331-5.
    PMID: 23956536 DOI: 10.4103/0972-0707.114364
    To evaluate physical properties and cytotoxicity of pure gypsum-based (pure-GYP) and experimental gypsum-based biomaterials mixed with polyacrylic acid (Gyp-PA). The results were compared with calcium hydroxide (CH) and glass ionomer cement (GIC) for application as base/liner materials.
    Matched MeSH terms: Glass Ionomer Cements
  18. Tailor-made Ge-doped silica-glass for clinical diagnostic X-ray dosimetry
    Alyahyawi A, Jupp T, Alkhorayef M, Bradley DA
    Appl Radiat Isot, 2018 Aug;138:45-49.
    PMID: 28780202 DOI: 10.1016/j.apradiso.2017.07.011
    In the modern clinical practice of diagnostic radiology there is a growing demand for radiation dosimetry, it also being recognized that with increasing use of X-ray examinations additional population dose will result, accompanied by an additional albeit low potential for genetic consequences. At the doses typical of diagnostic radiology there is also a low statistical risk for cancer induction; in adhering to best practice, to be also implied is a low but non-negligible potential for deterministic sensitive organ responses, including in regard to the skin and eyes. Risk reduction is important, in line with the principle of ALARP, both in regard to staff and patients alike; for the latter modern practice is usually guided by Dose Reference Levels (DRL) while for the former and members of the public, legislated controls (supported by safe working practices) pertain. As such, effective, reliable and accurate means of dosimetry are required in support of these actions. Recent studies have shown that Ge-doped-silica glass fibres offer several advantages over the well-established phosphor-based TL dosimeters (TLD), including excellent sensitivity at diagnostic doses as demonstrated herein, low fading, good reproducibility and re-usability, as well as representing a water impervious, robust dosimetric system. In addition, these silica-based fibres show good linearity over a wide dynamic range of dose and dose-rate and are directionally independent. In the present study, we investigate tailor made doped-silica glass thermoluminescence (TL) for applications in medical diagnostic imaging dosimetry. The aim is to develop a dosimeter of sensitivity greater than that of the commonly used LiF (Mg,Ti) phosphor. We examine the ability of such doped glass media to detect the typically low levels of radiation in diagnostic applications (from fractions of a mGy through to several mGy or more), including, mammography and dental radiology, use being made of x-ray tubes located at the Royal Surrey County Hospital. We further examine dose-linearity, energy response and fading.
    Matched MeSH terms: Glass*
  19. In vitro biocompatibility of hydroxyapatite-added GIC: An SEM study using human periodontal ligament fibroblasts
    Thomas B, Gupta K
    J Esthet Restor Dent, 2017 Nov 12;29(6):435-441.
    PMID: 28703476 DOI: 10.1111/jerd.12317
    OBJECTIVE: Nano-hydroxyapatite-added GIC has been developed to improve the physical properties of conventional GIC. However, biological response of periodontal cells to this potentially useful cervical restorative material has been unexplored. The aim of this study was to investigate the in vitro response of human periodontal ligament fibroblasts to hydroxyapatite-added GIC.

    MATERIALS AND METHODS: Three categories of materials, namely, test group 1 (cGIC or type IX GIC), test group 2 (HA-GIC or hydroxyapatite-added GIC), and positive control (glass cover slips) were incubated with human periodontal ligament fibroblasts. The samples were viewed under scanning electron microscope to study the morphological characteristics of fibroblasts. Additionally, elemental analysis was performed to differentiate between the two test groups based on surface chemical composition.

    RESULTS: Test group 1 (cGIC) exhibited cells with curled up morphology, indicative of poor attachment to the substrate. Test group 2 (Ha-GIC) exhibited cells with flattened morphology and numerous cellular extensions such as lamellipodia and blebs, indicative of good attachment to the substrate. The test group 2 (Ha-GIC) demonstrated higher surface elemental percentages of calcium and phosphorus.

    CONCLUSION: Within the limitations of this study, it may be concluded that hydroxyapatite-added GIC is more biocompatible than conventional GIC (type IX), probably attributed to high elemental percentages of calcium and phosphorus.

    CLINICAL SIGNIFICANCE: The search for an ideal cervical restorative dental material has been ever elusive. Hydroxyapatite-added GIC is a simple and economical dental material to fabricate from basic conventional GIC. The results from this study strengthen its candidature for cervical and root surface restorations which may later require soft tissue augmentation. The possibility of connective tissue adhesion to this material is an exciting prospect in the field of periorestorative dentistry.

    Matched MeSH terms: Glass Ionomer Cements/pharmacology*
  20. Bioglass® 45S5-based composites for bone tissue engineering and functional applications
    Rizwan M, Hamdi M, Basirun WJ
    J Biomed Mater Res A, 2017 Nov;105(11):3197-3223.
    PMID: 28686004 DOI: 10.1002/jbm.a.36156
    Bioglass® 45S5 (BG) has an outstanding ability to bond with bones and soft tissues, but its application as a load-bearing scaffold material is restricted due to its inherent brittleness. BG-based composites combine the amazing biological and bioactive characteristics of BG with structural and functional features of other materials. This article reviews the composites of Bioglass® in combination with metals, ceramics and polymers for a wide range of potential applications from bone scaffolds to nerve regeneration. Bioglass® also possesses angiogenic and antibacterial properties in addition to its very high bioactivity; hence, composite materials developed for these applications are also discussed. BG-based composites with polymer matrices have been developed for a wide variety of soft tissue engineering. This review focuses on the research that suggests the suitability of BG-based composites as a scaffold material for hard and soft tissues engineering. Composite production techniques have a direct influence on the bioactivity and mechanical behavior of scaffolds. A detailed discussion of the bioactivity, in vitro and in vivo biocompatibility and biodegradation is presented as a function of materials and its processing techniques. Finally, an outlook for future research is also proposed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3197-3223, 2017.
    Matched MeSH terms: Glass/chemistry*
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