Displaying publications 21 - 40 of 301 in total

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  1. The proliferation and tenogenic differentiation potential of bone marrow-derived mesenchymal stromal cell are influenced by specific uniaxial cyclic tensile loading conditions
    Nam HY, Pingguan-Murphy B, Amir Abbas A, Mahmood Merican A, Kamarul T
    Biomech Model Mechanobiol, 2015 Jun;14(3):649-63.
    PMID: 25351891 DOI: 10.1007/s10237-014-0628-y
    It has been previously demonstrated that mechanical stimuli are important for multipotent human bone marrow-derived mesenchymal stromal cells (hMSCs) to maintain good tissue homeostasis and even to enhance tissue repair processes. In tendons, this is achieved by promoting the cellular proliferation and tenogenic expression/differentiation. The present study was conducted to determine the optimal loading conditions needed to achieve the best proliferation rates and tenogenic differentiation potential. The effects of mechanical uniaxial stretching using different rates and strains were performed on hMSCs cultured in vitro. hMSCs were subjected to cyclical uniaxial stretching of 4, 8 or 12 % strain at 0.5 or 1 Hz for 6, 24, 48 or 72 h. Cell proliferation was analyzed using alamarBlue[Formula: see text] assay, while hMSCs differentiation was analyzed using total collagen assay and specific tenogenic gene expression markers (type I collagen, type III collagen, decorin, tenascin-C, scleraxis and tenomodulin). Our results demonstrate that the highest cell proliferation is observed when 4 % strain [Formula: see text] 1 Hz was applied. However, at 8 % strain [Formula: see text] 1 Hz loading, collagen production and the tenogenic gene expression were highest. Increasing strain or rates thereafter did not demonstrate any significant increase in both cell proliferation and tenogenic differentiation. In conclusion, our results suggest that 4 % [Formula: see text] 1 Hz cyclic uniaxial loading increases cell proliferation, but higher strains are required for superior tenogenic expressions. This study suggests that selected loading regimes will stimulate tenogenesis of hMSCs.
    Matched MeSH terms: Tensile Strength*
  2. Mechanical behaviour of in-situ chondrocytes subjected to different loading rates: a finite element study
    Moo EK, Herzog W, Han SK, Abu Osman NA, Pingguan-Murphy B, Federico S
    Biomech Model Mechanobiol, 2012 Sep;11(7):983-93.
    PMID: 22234779 DOI: 10.1007/s10237-011-0367-2
    Experimental findings indicate that in-situ chondrocytes die readily following impact loading, but remain essentially unaffected at low (non-impact) strain rates. This study was aimed at identifying possible causes for cell death in impact loading by quantifying chondrocyte mechanics when cartilage was subjected to a 5% nominal tissue strain at different strain rates. Multi-scale modelling techniques were used to simulate cartilage tissue and the corresponding chondrocytes residing in the tissue. Chondrocytes were modelled by accounting for the cell membrane, pericellular matrix and pericellular capsule. The results suggest that cell deformations, cell fluid pressures and fluid flow velocity through cells are highest at the highest (impact) strain rate, but they do not reach damaging levels. Tangential strain rates of the cell membrane were highest at the highest strain rate and were observed primarily in superficial tissue cells. Since cell death following impact loading occurs primarily in superficial zone cells, we speculate that cell death in impact loading is caused by the high tangential strain rates in the membrane of superficial zone cells causing membrane rupture and loss of cell content and integrity.
    Matched MeSH terms: Tensile Strength
  3. A hyperelastic fibre-reinforced continuum model of healing tendons with distributed collagen fibre orientations
    Bajuri MN, Isaksson H, Eliasson P, Thompson MS
    Biomech Model Mechanobiol, 2016 12;15(6):1457-1466.
    PMID: 26951049
    The healing process of ruptured tendons is problematic due to scar tissue formation and deteriorated material properties, and in some cases, it may take nearly a year to complete. Mechanical loading has been shown to positively influence tendon healing; however, the mechanisms remain unclear. Computational mechanobiology methods employed extensively to model bone healing have achieved high fidelity. This study aimed to investigate whether an established hyperelastic fibre-reinforced continuum model introduced by Gasser, Ogden and Holzapfel (GOH) can be used to capture the mechanical behaviour of the Achilles tendon under loading during discrete timepoints of the healing process and to assess the model's sensitivity to its microstructural parameters. Curve fitting of the GOH model against experimental tensile testing data of rat Achilles tendons at four timepoints during the tendon repair was used and achieved excellent fits ([Formula: see text]). A parametric sensitivity study using a three-level central composite design, which is a fractional factorial design method, showed that the collagen-fibre-related parameters in the GOH model-[Formula: see text] and [Formula: see text]-had almost equal influence on the fitting. This study demonstrates that the GOH hyperelastic fibre-reinforced model is capable of describing the mechanical behaviour of healing tendons and that further experiments should focus on establishing the structural and material parameters of collagen fibres in the healing tissue.
    Matched MeSH terms: Tensile Strength
  4. Development of a bone substitute material based on alpha-tricalcium phosphate scaffold coated with carbonate apatite/poly-epsilon-caprolactone
    Bang LT, Ramesh S, Purbolaksono J, Long BD, Chandran H, Ramesh S, et al.
    Biomed Mater, 2015 Aug;10(4):045011.
    PMID: 26225725 DOI: 10.1088/1748-6041/10/4/045011
    Interconnected porous tricalcium phosphate ceramics are considered to be potential bone substitutes. However, insufficient mechanical properties when using tricalcium phosphate powders remain a challenge. To mitigate these issues, we have developed a new approach to produce an interconnected alpha-tricalcium phosphate (α-TCP) scaffold and to perform surface modification on the scaffold with a composite layer, which consists of hybrid carbonate apatite / poly-epsilon-caprolactone (CO3Ap/PCL) with enhanced mechanical properties and biological performance. Different CO3Ap combinations were tested to evaluate the optimal mechanical strength and in vitro cell response of the scaffold. The α-TCP scaffold coated with CO3Ap/PCL maintained a fully interconnected structure with a porosity of 80% to 86% and achieved an improved compressive strength mimicking that of cancellous bone. The addition of CO3Ap coupled with the fully interconnected microstructure of the α-TCP scaffolds coated with CO3Ap/PCL increased cell attachment, accelerated proliferation and resulted in greater alkaline phosphatase (ALP) activity. Hence, our bone substitute exhibited promising potential for applications in cancellous bone-type replacement.
    Matched MeSH terms: Tensile Strength
  5. Wavelet neural networks applied to pulping of oil palm fronds
    Zainuddin Z, Wan Daud WR, Pauline O, Shafie A
    Bioresour Technol, 2011 Dec;102(23):10978-86.
    PMID: 21996481 DOI: 10.1016/j.biortech.2011.09.080
    In the organosolv pulping of the oil palm fronds, the influence of the operational variables of the pulping reactor (viz. cooking temperature and time, ethanol and NaOH concentration) on the properties of the resulting pulp (yield and kappa number) and paper sheets (tensile index and tear index) was investigated using a wavelet neural network model. The experimental results with error less than 0.0965 (in terms of MSE) were produced, and were then compared with those obtained from the response surface methodology. Performance assessment indicated that the neural network model possessed superior predictive ability than the polynomial model, since a very close agreement between the experimental and the predicted values was obtained.
    Matched MeSH terms: Tensile Strength
  6. Bionanocomposites of regenerated cellulose/zeolite prepared using environmentally benign ionic liquid solvent
    Soheilmoghaddam M, Wahit MU, Tuck Whye W, Ibrahim Akos N, Heidar Pour R, Ali Yussuf A
    Carbohydr Polym, 2014 Jun 15;106:326-34.
    PMID: 24721086 DOI: 10.1016/j.carbpol.2014.02.085
    Bionanocomposite films based on regenerated cellulose (RC) and incorporated with zeolite at different concentrations were fabricated by dissolving cellulose in 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid using a simple green method. The interactions between the zeolite and the cellulose matrix were confirmed by Fourier transform infrared spectra. Mechanical properties of the nanocomposite films significantly improved as compared with the pure regenerated cellulose film, without the loss of extensibility. Zeolite incorporation enhanced the thermal stability and char yield of the nanocomposites. The scanning electron microscopy and transmission electron microscopy showed that zeolite was uniformly dispersed in the regenerated cellulose matrix. In vitro cytotoxicity test demonstrated that both RC and RC/zeolite nanocomposite films are cytocompatible. These results indicate that the prepared nanocomposites have potential applications in biodegradable packaging, membranes and biomedical areas.
    Matched MeSH terms: Tensile Strength
  7. Production and modification of nanofibrillated cellulose using various mechanical processes: a review
    Abdul Khalil HP, Davoudpour Y, Islam MN, Mustapha A, Sudesh K, Dungani R, et al.
    Carbohydr Polym, 2014 Jan;99:649-65.
    PMID: 24274556 DOI: 10.1016/j.carbpol.2013.08.069
    Nanofibrillated cellulose from biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. Although they still suffer from two major drawbacks. The first challenge is the exploration of raw materials and its application in nanocomposites production. Second one is high energy consumption regarding the mechanical fibrillation. However, pretreatments before mechanical isolation can overcome this problem. Hydrophilic nature of nano-size cellulose fibers restricts good dispersion of these materials in hydrophobic polymers and therefore, leads to lower mechanical properties. Surface modification before or after mechanical defibrillation could be a solution for this problem. Additionally, drying affects the size of nanofibers and its properties which needs to study further. This review focuses on recent developments in pretreatments, nanofibrillated cellulose production and its application in nanopaper applications, coating additives, security papers, food packaging, and surface modifications and also for first time its drying.
    Matched MeSH terms: Tensile Strength
  8. Development of regenerated cellulose/halloysites nanocomposites via ionic liquids
    Hanid NA, Wahit MU, Guo Q, Mahmoodian S, Soheilmoghaddam M
    Carbohydr Polym, 2014 Jan;99:91-7.
    PMID: 24274483 DOI: 10.1016/j.carbpol.2013.07.080
    In this study, regenerated cellulose/halloysites (RC/HNT) nanocomposites with different nanofillers loading were fabricated by dissolving the cellulose in 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid. The films were prepared via solution casting method and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical properties were investigated by tensile testing. It clearly displayed a good enhancement of both tensile strength and Young's modulus with HNT loading up to 5 wt%. As the HNT loadings increased to 5 wt%, the thermal behaviour and water resistance rate was also increased. The TEM and SEM images also depicted even dispersion of the HNT and a good intertubular interaction between the HNT and the cellulose matrix.
    Matched MeSH terms: Tensile Strength
  9. Characterization of α-tocopherol as interacting agent in polyvinyl alcohol-starch blends
    Sin LT, Bee ST, Tee TT, Kadhum AA, Ma C, Rahmat AR, et al.
    Carbohydr Polym, 2013 Nov 6;98(2):1281-7.
    PMID: 24053804 DOI: 10.1016/j.carbpol.2013.07.069
    In this study, the interactions of α-tocopherol (α-TOH) in PVOH-starch blends were investigated. α-TOH is an interacting agent possesses a unique molecule of polar chroman "head" and non-polar phytyl "tail" which can improve surface interaction of PVOH and starch. It showed favorable results when blending PVOH-starch with α-TOH, where the highest tensile strengths were achieved at 60 wt.% PVOH-starch blend for 1 phr α-TOH and 50 wt.% for 3 phr α-TOH, respectively. This due to the formation of miscible PVOH-starch as resulted by the compatibilizing effect of α-TOH. Moreover, the enthalpy of melting (ΔHm) of 60 wt.% PVOH-starch and 50 wt.% PVOH-starch added with 1 and 3 phr α-TOH respectively were higher than ΔHm of the neat PVOH-starch blends. The thermogravimetry analysis also showed that α-TOH can be used as thermal stabilizer to reduce weight losses at elevated temperature. The surface morphologies of the compatible blends formed large portion of continuous phase where the starch granules interacted well with α-TOH by acting as compatilizer to reduce surface energy of starch for embedment into PVOH matrix.
    Matched MeSH terms: Tensile Strength
  10. Sugar palm (Arenga pinnata): Its fibres, polymers and composites
    Ishak MR, Sapuan SM, Leman Z, Rahman MZ, Anwar UM, Siregar JP
    Carbohydr Polym, 2013 Jan 16;91(2):699-710.
    PMID: 23121967 DOI: 10.1016/j.carbpol.2012.07.073
    Sugar palm (Arenga pinnata) is a multipurpose palm species from which a variety of foods and beverages, timber commodities, biofibres, biopolymers and biocomposites can be produced. Recently, it is being used as a source of renewable energy in the form of bio-ethanol via fermentation process of the sugar palm sap. Although numerous products can be produced from sugar palm, three products that are most prominent are palm sugar, fruits and fibres. This paper focuses mainly on the significance of fibres as they are highly durable, resistant to sea water and because they are available naturally in the form of woven fibre they are easy to process. Besides the recent advances in the research of sugar palm fibres and their composites, this paper also addresses the development of new biodegradable polymer derived from sugar palm starch, and presents reviews on fibre surface treatment, product development, and challenges and efforts on properties enhancement of sugar palm fibre composites.
    Matched MeSH terms: Tensile Strength
  11. Potential of using multiscale kenaf fibers as reinforcing filler in cassava starch-kenaf biocomposites
    Zainuddin SY, Ahmad I, Kargarzadeh H, Abdullah I, Dufresne A
    Carbohydr Polym, 2013 Feb 15;92(2):2299-305.
    PMID: 23399291 DOI: 10.1016/j.carbpol.2012.11.106
    Biodegradable materials made from cassava starch and kenaf fibers were prepared using a solution casting method. Kenaf fibers were treated with NaOH, bleached with sodium chlorite and acetic buffer solution, and subsequently acid hydrolyzed to obtain cellulose nanocrystals (CNCs). Biocomposites in the form of films were prepared by mixing starch and glycerol/sorbitol with various filler compositions (0-10 wt%). X-ray diffraction revealed that fiber crystallinity increased after each stage of treatment. Morphological observations and size reductions of the extracted cellulose and CNCs were studied using field emission scanning electron microscopy and transmission electron microscopy. The effects of different treatments and filler contents of the biocomposites were evaluated through mechanical tests. Results showed that the tensile strengths and moduli of the biocomposites increased after each treatment and the optimum filler content was 6%.
    Matched MeSH terms: Tensile Strength
  12. Development and characterization of sugar palm starch and poly(lactic acid) bilayer films
    Sanyang ML, Sapuan SM, Jawaid M, Ishak MR, Sahari J
    Carbohydr Polym, 2016 08 01;146:36-45.
    PMID: 27112848 DOI: 10.1016/j.carbpol.2016.03.051
    The development and characterization of environmentally friendly bilayer films from sugar palm starch (SPS) and poly(lactic acid) (PLA) were conducted in this study. The SPS-PLA bilayer films and their individual components were characterized for their physical, mechanical, thermal and water barrier properties. Addition of 50% PLA layer onto 50% SPS layer (SPS50-PLA50) increased the tensile strength of neat SPS film from 7.74 to 13.65MPa but reduced their elongation at break from 46.66 to 15.53%. The incorporation of PLA layer significantly reduced the water vapor permeability as well as the water uptake and solubility of bilayer films which was attributed to the hydrophobic characteristic of the PLA layer. Furthermore, scanning electron microscopy (SEM) image of SPS50-PLA50 revealed lack of strong interfacial adhesion between the SPS and PLA. Overall, the incorporation of PLA layer onto SPS films enhances the suitability of SPS based films for food packaging.
    Matched MeSH terms: Tensile Strength
  13. Cellulose acetate from oil palm empty fruit bunch via a one step heterogeneous acetylation
    Wan Daud WR, Djuned FM
    Carbohydr Polym, 2015 Nov 5;132:252-60.
    PMID: 26256348 DOI: 10.1016/j.carbpol.2015.06.011
    Acetone soluble oil palm empty fruit bunch cellulose acetate (OPEFB-CA) of DS 2.52 has been successfully synthesized in a one-step heterogeneous acetylation of OPEFB cellulose without necessitating the hydrolysis stage. This has only been made possible by the mathematical modeling of the acetylation process by manipulating the variables of reaction time and acetic anhydride/cellulose ratio (RR). The obtained model was verified by experimental data with an error of less than 2.5%. NMR analysis showed that the distribution of the acetyl moiety among the three OH groups of cellulose indicates a preference at the C6 position, followed by C3 and C2. XRD revealed that OPEFB-CA is highly amorphous with a degree of crystallinity estimated to be ca. 6.41% as determined from DSC. The OPEFB-CA films exhibited good mechanical properties being their tensile strength and Young's modulus higher than those of the commercial CA.
    Matched MeSH terms: Tensile Strength
  14. Study on a Novel natural cellulosic fiber from Kigelia africana fruit: Characterization and analysis
    Siva R, Valarmathi TN, Palanikumar K, Samrot AV
    Carbohydr Polym, 2020 Sep 15;244:116494.
    PMID: 32536404 DOI: 10.1016/j.carbpol.2020.116494
    In recent days, there is an increasing use of green composites in composite manufacturing, where cellulosic natural fibers have been started using for this purpose. In line with this, a novel cellulose fiber was extracted from the Kigelia africana fruit and its physical, chemical and thermal properties, crystallography and surface morphology analysis were studied and reported in this investigative research paper. The physical analysis revealed the mean tensile strength as 50.31 ± 24.71 to 73.12 ± 32.48 MPa, diameter as 0.507 ± 0.162 to 0.629 ± 0.182 mm and density as 1.316 g/cm³ for the Kigelia africana fiber. The proximate chemical analysis estimated the cellulose percentage to be 61.5 % and the existence of different basic components like cellulose, hemicellulose and lignin are confirmed by Fourier transform infrared spectroscopy analysis. Thermogravimetric analysis establishes the thermal stability of the fiber as 212 ⁰C. The crystallinity index, 57.38 % of the fiber was determined by X-ray diffraction. Surface morphology by field emission scanning electron microscopy reveals the presence of protrusions in fiber which aid in the better adhesion with the matrix in composite manufacturing.
    Matched MeSH terms: Tensile Strength
  15. Preparation and characterization of nanocrystalline cellulose from Acacia mangium and its reinforcement potential
    Jasmani L, Adnan S
    Carbohydr Polym, 2017 Apr 01;161:166-171.
    PMID: 28189225 DOI: 10.1016/j.carbpol.2016.12.061
    Acacia mangium, a fast growing tree is widely planted in Malaysia. Converting Acacia wood into nanocellulose could create new value added products for forest-based industry. Nanocrystalline cellulose (NCC) was prepared from Acacia mangium wood pulp via 64wt% sulfuric acid hydrolysis. Prior to acid hydrolysis, Acacia mangium was subjected to pulping followed by bleaching in order to remove non-cellulosic fragments. Acid hydrolysis was carried out on bleached pulp to produce the needle-like NCC with 79% crystallinity and aspect ratio of 26. The resulting NCC was mixed with PVA as a reinforcement material. Incorporation of 2% NCC improved the tensile of the NCC-PVA film by 30%.
    Matched MeSH terms: Tensile Strength
  16. Preparation and characterization of bioplastics from silylated cassava starch and epoxidized soybean oils
    Yang J, Xu S, Wang W, Ran X, Ching YC, Sui X, et al.
    Carbohydr Polym, 2023 Jan 15;300:120253.
    PMID: 36372510 DOI: 10.1016/j.carbpol.2022.120253
    In this work, a systematic coupling study of silane coupling agent between starch and epoxidized soybean oils (ESO) was carried out. Starch was modified by 3-aminopropyl trimethoxy silane (APMS) with various contents of NaOH. The APMS-modified starch was incorporated with ESO to synthesize the bioplastics by solution casting. As demonstrated by the FTIR spectra, the hydrogen bond interactions among starch molecules were inhibited by the modification. This outcome provided higher interaction and compatibility of starch with ESO, as confirmed by FESEM. TGA showed that the thermal stability of starch decreased considerably after the silylation. In contrast, the produced bioplastics with silylated starch exhibited higher thermal stability than the control sample. Regarding the bioplastics, an obvious increase of tensile strength from 5.78 MPa to 9.29 MPa was obtained. This work suggested a simple and effective modification technique by APMS to improve compatibility of starch/ESO-based bioplastics with superior mechanical and thermal properties.
    Matched MeSH terms: Tensile Strength
  17. Preparation and characterization of curdlan/nanocellulose blended film and its application to chilled meat preservation
    Qian Y, Bian L, Wang K, Chia WY, Khoo KS, Zhang C, et al.
    Chemosphere, 2021 Mar;266:128948.
    PMID: 33220979 DOI: 10.1016/j.chemosphere.2020.128948
    In this study, to improve the mechanical and thermal properties of curdlan film, a curdlan/nanocellulose (NC) blended film was prepared and characterized for the first time. NC was successfully prepared from microcrystalline cellulose (MCC) with NaOH/urea treatment. The particle size of NC was observed to be 70-140 nm by cryo-electron microscope (cryo-EM). The blended film was prepared by adding the NC to curdlan solution. The tensile strength (TS) of the blended film reached the maximum value of 38.6 MPa, and the elongation at break (EB) was 40%. The DSC curve showed that the heat absorption peak of the film was 240 °C, indicating that the blended film has good temperature stability. Additionally, some other film properties were also improved, including gas barrier properties and transparency. Obvious morphological and molecular differences between the blended film and the pure curdlan film were discovered by SEM and FTIR analysis. Finally, the blended film was used for the preservation of chilled meat and extended the storage time of meat to 12 days. These results provided a theoretical basis for future application and development of biodegradable film.
    Matched MeSH terms: Tensile Strength
  18. The effects of alpha-tocopherol supplementation on fracture healing in a postmenopausal osteoporotic rat model
    Mohamad S, Shuid AN, Mohamed N, Fadzilah FM, Mokhtar SA, Abdullah S, et al.
    Clinics (Sao Paulo), 2012 Sep;67(9):1077-85.
    PMID: 23018307
    OBJECTIVE: Osteoporosis increases the risk of bone fractures and may impair fracture healing. The aim of this study was to investigate whether alpha-tocopherol can improve the late-phase fracture healing of osteoporotic bones in ovariectomized rats.

    METHOD: In total, 24 female Sprague-Dawley rats were divided into three groups. The first group was sham-operated, and the other two groups were ovariectomized. After two months, the right femora of the rats were fractured under anesthesia and internally repaired with K-wires. The sham-operated and ovariectomized control rat groups were administered olive oil (a vehicle), whereas 60 mg/kg of alpha-tocopherol was administered via oral gavage to the alpha-tocopherol group for six days per week over the course of 8 weeks. The rats were sacrificed, and the femora were dissected out. Computed tomography scans and X-rays were performed to assess fracture healing and callus staging, followed by the assessment of callus strengths through the biomechanical testing of the bones.

    RESULTS: Significantly higher callus volume and callus staging were observed in the ovariectomized control group compared with the sham-operated and alpha-tocopherol groups. The ovariectomized control group also had significantly lower fracture healing scores than the sham-operated group. There were no differences between the alpha-tocopherol and sham-operated groups with respect to the above parameters. The healed femora of the ovariectomized control group demonstrated significantly lower load and strain parameters than the healed femora of the sham-operated group. Alpha-tocopherol supplementation was not able to restore these biomechanical properties.

    CONCLUSION: Alpha-tocopherol supplementation appeared to promote bone fracture healing in osteoporotic rats but failed to restore the strength of the fractured bone.

    Matched MeSH terms: Tensile Strength
  19. Fulltext Feasibility of using latex examination gloves as dental dam: a tensile strength study
    Budi Aslinie Md Sabri, Nur Hidayah Mohd Radzi, Fatimatuz Zahira Abdul Hadi, Ikmal HishamIsmai
    Compendium of Oral Science, 2015;2(1):6-13.
    MyJurnal
    Objective: To evaluate feasibility of hand gloves as a rubber dam isolation alternative, in respect of physical properties. Materials and Methods: A randomized controlled trial study design was used. Three types of gloves were tested with two types of a rubber dam used as the control group. Cut-out pattern of dumb-bell shapes were made from 35 samples for each type of groups and tensile strength were tested using Universal Testing Machine and the Trapezium X software. All tests for physical requirements were performed in accord-ance with American Society for Testing and Materials D412, Standard Test Methods for Vulcanized Rubber and Thermoplastic Rubbers and Thermoplastic Elastomers-Tension. Findings were analyzed by analysis of vari-ance (ANOVA) and differences were compared using a Tukey-Kramer interval calculated at the 0.05 signifi-cance level. Results: Heavy gauge rubber dam has the highest Mean (calculated at the 0.05 significance level) except for maximum stress calculated at entire area. Medium-gauge rubber dam has significantly higher tensile strength (44.5075 N/mm2) when compared to heavy-gauge rubber dam (35.7787 N/mm2) although it was 0.09mm thinner. Discovery 2020 Powder Free Latex Examination Gloves with tensile strength value of 28.5922 N/mm2 (±3.27366) is more than the minimum requirement specified by American Federal Specification ZZ-R90B Rubber Dam (Dental, 1985) (4000 pounds per square inch or 27.6 N/mm2). For all variable tested, all groups are significantly different from each other. The mean square between the groups was quite large. Conclusion: This study shows that there are significant differences between the physical strength of latex gloves when com-pared to rubber dam. However, the comparison between thickness and tensile strength among various rubber dam, did not correspond proportionately. Only one type of rubber gloves met the minimum requirement but that is just one aspect. In view of these mixed results, more research is needed before we can conclude that it is feasable that we use hand gloves to replace rubber dam.
    Matched MeSH terms: Tensile Strength
  20. Fulltext Bond strengths of composite resins used for the attachment of bonded retainers
    Sinniah, Saraswathy D., Jones, Steven P., Georgiou, George, Cunningham, Susan J., Petrie, Aviva
    Compendium of Oral Science, 2016;3(1):17-24.
    MyJurnal
    used with bonded retainers. Setting: Department of Orthodontics, UCL Eastman Dental Institute, United Kingdom. Methods: Flowable composite resins (Transbond TM Supreme LV, StarFlowTM and Tetric EvoFlow®) and non -flowable control resin (TransbondTM LR) were made into cylinders prior to bonding to hydoxyapatite discs. They were then mounted into jigs and tested in the InstronTM Universal Testing Machine in both shear and tensile modes. Results: The highest mean shear bond strength was seen with StarFlow TM (14.09 MPa), which was significantly higher than both TransbondTM LR (9.48 MPa) and TransbondTM Supreme LV (8.20 MPa). The mean shear bond strength of Tetric EvoFlow® (11.86 MPa) was also significantly higher than TransbondTM Supreme LV. The highest mean tensile bond strength was seen with Tetric EvoFlow® (2.14 MPa), which was significantly higher than TransbondTM LR (1.15 MPa) and TransbondTM Supreme LV (0.61 MPa) but not significantly different to StarFlowTM (1.47 MPa). For shear loading, StarFlowTM had the highest 50th percentile survival estimate at 15.10 MPa, followed by Tetric EvoFlow® (13.00 MPa) and TransbondTM Supreme LV (7.50 MPa). TransbondTM LR had a 50th percentile estimate at 9.00 MPa. For tensile loading, Tetric EvoFlow® had the highest 50th percentile survival estimate at 2.50 MPa, followed by StarFlowTM (1.30 MPa) and TransbondTM Supreme LV (0.50 MPa). TransbondTM LR had a 50th percentile estimate at 1.00 MPa. Conclusions: Mean shear bond strengths for all of the resins were significantly higher than the mean tensile bond strengths. StarFlowTM and Tetric EvoFlow® could potentially be suitable clinical alternatives to TransbondTM LR due to its low viscosity flow characteristics and adequate shear and tensile bond strengths.
    Matched MeSH terms: Tensile Strength
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