scholarly journals Effect of Surface Treated Silicon Dioxide Nanoparticles on Some Mechanical Properties of Maxillofacial Silicone Elastomer

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Sara M. Zayed ◽  
Ahmad M. Alshimy ◽  
Amal E. Fahmy
Keyword(s):  
Mechanical Properties ◽  
Silicon Dioxide ◽  
Soft Tissues ◽  
Study Groups ◽  
Silicone Elastomer ◽  
Control Group ◽  
Silicon Dioxide Nanoparticles ◽  
Natural Behavior ◽  
Materials Used ◽  
Facial Soft Tissues

Current materials used for maxillofacial prostheses are far from ideal and there is a need for novel improved materials which mimic as close as possible the natural behavior of facial soft tissues. This study aimed to evaluate the effect of adding different concentrations of surface treated silicon dioxide nanoparticles (SiO2) on clinically important mechanical properties of a maxillofacial silicone elastomer. 147 specimens of the silicone elastomer were prepared and divided into seven groups (n=21). One control group was prepared without nanoparticles and six study groups with different concentrations of nanoparticles, from 0.5% to 3% by weight. Specimens were tested for tear strength (ASTM D624), tensile strength (ASTM D412), percent elongation, and shore A hardness. SEM was used to assess the dispersion of nano-SiO2within the elastomer matrix. Data were analyzed by one-way ANOVA and Scheffe test (α=0.05). Results revealed significant improvement in all mechanical properties tested, as the concentration of the nanoparticles increased. This was supported by the results of the SEM. Hence, it can be concluded that the incorporation of surface treated SiO2nanoparticles at concentration of 3% enhanced the overall mechanical properties of A-2186 silicone elastomer.

scholarly journals Evaluation of Some Mechanical Properties of a Maxillofacial Silicon Elastomer Reinforced with Polyester Powder

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Yagthan Mohammed Haider ◽  
Zainab Salih Abdullah ◽  
Ghasak H. Jani ◽  
Norehan Mokhtar
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Hardness Test ◽  
Silicone Elastomer ◽  
Control Group ◽  
Silicone Elastomers ◽  
Tear Strength ◽  
To Come ◽  
Post Hoc

Maxillofacial silicone elastomers are used to replace and reconstruct missing facial parts for patients with trauma or a certain disease. Although commonly favorable silicone elastomers are not ideal in properties, many studies have been carried out to improve their mechanical properties and to come out with ideal maxillofacial prosthetic materials, so as to render patients with the best maxillofacial prostheses. The aim of the current study is to evaluate the effect of addition of different concentrations of polyester powder on hardness, tear strength, surface roughness, and tensile strength of maxillofacial A-2186 RTV silicone elastomers. Polyester powder was added to the silicone elastomer in the concentrations of 1%, 3% and 5% by using an electronic digital balance, compared with the control group of 0% polyester filler. The shore A hardness test was done according to ASTM D 2240 standards. The tear test was done according to ASTM D624 type C standards. The tensile test was done according to ISO specification number 37:2011. The surface roughness test was performed according to ISO 7619-1 2010 specifications. The data collected were then analyzed using one-way analysis of variance (ANOVA) and post hoc and Fisher’s LSD tests. All three groups showed a highly significant increase in tear strength, tensile strength, hardness, and roughness, compared to the control group. Reinforcement of A-2186 Platinum RTV Silicone Elastomer with 5% polyester significantly improved the mechanical properties tested in this study.

EFFECT OF SILICON DIOXIDE NANOPARTICLES ON MECHANICAL PROPERTIES OF CARBON FIBER/UNSATURATED POLYESTER COMPOSITE

2021 ◽  
Vol 25 (Special) ◽  
pp. 2-91-2-98
Author(s):  
Ghufran K. Nahedh ◽  
◽  
Amer H. Majeed ◽  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Silicon Dioxide ◽  
Unsaturated Polyester ◽  
Impact Resistance ◽  
Weight Ratio ◽  
Dispersion Method ◽  
Silicon Dioxide Nanoparticles ◽  
Polyester Composite ◽  
Partial Weight

This study deals with the effect of silicon dioxide nanoparticles (SiO2NPs) on the mechanical properties of polymer matrix composite (PMC). The nanocomposites were prepared by adding carbon fiber (CF1.5%) to the unsaturated polyester resin, and then different proportions of SiO2 NPs (1 to 4% by weight) were added using the ultrasonic bath machine dispersion method. The results showed that the tensile strength decreases with the increase in the partial weight of SiO2. Impact resistance, bending and compressive strength were improved by (50.67%, 10.2%, and 18.14%) respectively at 2% by weight, then these properties decreased with the increase in weight ratio of (SiO2), and the hardness was improved by (19.7%) at 3% by weight. The present study aims to study the effect of adding silicon dioxide nanoparticles on the mechanical properties (tensile properties, compression, hardness and bending) of carbon fiber reinforced unsaturated polyester composite.

EFFECTS OF CULTURE PERIODS AND LOADING ON BIOMECHANICAL PROPERTIES OF SHEEP COLLAGEN FASCICLES

2014 ◽  
Vol 14 (06) ◽  
pp. 1440010
Author(s):  
AHMET C. CILINGIR
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Soft Tissues ◽  
Culture Media ◽  
Experimental Studies ◽  
Biomechanical Properties ◽  
Collagen Fibrils ◽  
Tangent Modulus ◽  
Control Group ◽  
Stress Strain

Soft tissues (e.g., tendon, skin, cartilage) change their dimensions and properties in response to applied mechanical stress/strain, which is called remodeling. Experimental studies using tissue cultures were performed to understand the biomechanical properties of collagen fascicles under mechanical loads. Collagen fascicles were dissected from sheep Achilles tendons and loaded under 1, 2, and 3 kg for 2, 4, and 6 days under culture. The mechanical properties of collagen fascicles after being loaded into the culture media were determined using tensile tester, and resultant stress–strain curves, tangent modulus, tensile strength, and strain at failure values were compared with those in a non-loaded and non-cultured control group of fascicles. The tangent modulus and tensile strength of the collagen fascicles increased with the increasing remodeling load after two days of culture. However, these values gradually decreased with the increasing culture period compared with the control group. According to the results obtained in this study, the mechanical properties of collagen fascicles were improved by loading at two days of culture, most likely due to the remodeling of collagen fibers. However, after a period of remodeling, local strains on the collagen fibrils increased, and finally, the collagen fibrils broke down, decreasing the mechanical properties of the tissue.

scholarly journals The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10213
Author(s):  
Anna Shipov ◽  
Paul Zaslansky ◽  
Heinrich Riesemeier ◽  
Gilad Segev ◽  
Ayelet Atkins ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Study Groups ◽  
Structural Features ◽  
Estrogen Deficiency ◽  
Control Group ◽  
Sprague Dawley ◽  
Post Menopausal Osteoporosis ◽  
Lamellar Region ◽  
Post Menopausal

Background Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone. Methods Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used.Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation. Results Cortical bone of both study groups contains two distinct regions: organized circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm3 vs 232 ± 106 µm3, P < 0.001 and 195 ± 86 µm3 vs. 247 ± 106 µm3, P < 0.001, respectively). Lacunar density was also lower in both bone regions of the OVH group (40 ± 18 ×103 lacunae/mm3 vs. 47 ± 9×103 lacunae/mm3 in the lamellar region, P = 0.003 and 63 ± 18×103lacunae/mm3 vs. 75 ± 13×103 lacunae/mm3 in the disorganized region, P < 0.001). Vascular canal volume was lower in the disorganized region of the bone in the OVH group compared to the same region in the control group (P < 0.001). Indentation moduli were not different between the study groups in both bone regions. Discussion Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of these results to humans due to major structural differences between human and rat bone.

scholarly journals Infiltration of Rhodamin B into three materials used as cervical barrier

2014 ◽  
Vol 62 (3) ◽  
pp. 235-242
Author(s):  
Grazielle Morais de SOUZA ◽  
Luis Cardoso RASQUIN ◽  
Fabíola Bastos de CARVALHO
Keyword(s):  
Study Groups ◽  
Control Group ◽  
Sodium Perborate ◽  
Filling Material ◽  
Significant Difference ◽  
Materials Used ◽  
Level Of Significance ◽  
Material Setting ◽  
Rhodamin B

OBJECTIVE: To evaluate in vitro the sealing ability of three materials used as cervical barrier for internal dental bleaching. METHODS: Thirty-three canines were selected, and after biomechanical root canal preparation, the canals were filled by lateral condensation technique. After the filling material setting reaction, the teeth were randomly divided into three groups of ten teeth each, according to the following materials for constructing the cervical barrier: X Temp LC; Vitro Fil; Coltosol. The control group consisted of three teeth, without placement of the cervical cap. Sodium perborate /distilled water associated with 2% Rhodamin B were used as bleaching substance. After placing the bleaching agent in the pulp chamber, access cavities were sealed with temporary cement IRM and samples were stored at 37 ° for 7 days. After this period, the samples were cleaved longitudinally, and leakage was evaluated by the visual method. The data were submitted to Pearson test with a 5% level of significance. RESULTS: No statistically significant difference was found between the study groups, however, the largest number of specimens with a lower degree of leakage were found in the Coltosol group. CONCLUSION: All the materials evaluated for making the cervical cap allowed some level of leakage.

scholarly journals Comparing the effects of manual and ultrasonic instrumentation on root surface mechanical properties

2016 ◽  
Vol 10 (04) ◽  
pp. 517-521 ◽  
Author(s):  
Muhammad Sohail Zafar
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Study Groups ◽  
Control Group ◽  
Maximum Height ◽  
Root Planing ◽  
Average Maximum ◽  
Significant Difference ◽  
Group 2 ◽  
Group 1

ABSTRACT Objective: The aim of the current study is to analyze the surface profiles of healthy and periodontal-treated roots. In addition, manual and ultrasonic instrumentation methods have been compared in terms of surface mechanical properties of root surfaces including surface roughness, hardness, and elastic modulus. Materials and Methods: This study was conducted using extracted teeth that were randomly divided into two study groups (1 and 2). Root planing was performed using either Gracey curettes (Group 1) or ultrasonic scaler (Group 2). The noncontact profilometer was used to analyze surface roughness before and after root planing. A nanoindenter was used to analyze the surface mechanical properties. Results: The root planing treatment reduced the peak and valley heights hence decreasing the surface roughness. The average maximum height of peaks (Sp) and average maximum height of valleys (Sv) for control groups remain 83.08 ± 18.47 μm and 117.58 ± 18.02 μm. The Sp was reduced to 32.86 ± 7.99 μm and 62.11 ± 16.07 μm for Groups 1 and 2, respectively. The Sv was reduced to 49.32 ± 29.51 μm for Group 1 and 80.87 ± 17.99 μm Group 2. The nanohardness and modulus of elasticity for cementum of the control group remain 0.28 ± 0.13 GPa and 5.09 ± 2.67 GPa, respectively. Conclusions: Gracey curettes and ultrasonic scalers are capable of significantly reducing the roughness following root planing. Although Gracey curettes produced smoother surfaces than ultrasonic scalers, there was no significant difference.

scholarly journals Bio-Inspired Hydrogels via 3D Bioprinting

2020 ◽  
Author(s):  
Lei Nie ◽  
Can Wang ◽  
Yaling Deng ◽  
Amin Shavandi
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Human Body ◽  
Biomedical Applications ◽  
Soft Tissues ◽  
3D Bioprinting ◽  
Potential Applications ◽  
Materials Used ◽  
Living Organisms ◽  
Traditional Manufacturing

Many soft tissues of the human body such as cartilages, muscles, and ligaments are mainly composed of biological hydrogels possessing excellent mechanical properties and delicate structures. Nowadays, bio-inspired hydrogels have been intensively explored due to their promising potential applications in tissue engineering. However, the traditional manufacturing technology is challenging to produce the bio-inspired hydrogels, and the typical biological composite topologies of bio-inspired hydrogels are accessible completed using 3D bioprinting at micrometer resolution. In this chapter, the 3D bioprinting techniques used for the fabrication of bio-inspired hydrogels were summarized, and the materials used were outlined. This chapter also focuses on the applications of bio-inspired hydrogels fabricated using available 3D bioprinting technologies. The development of 3D bioprinting techniques in the future would bring us closer to the fabrication capabilities of living organisms, which would be widely used in biomedical applications.

Incorporation of silicon dioxide nanoparticles at the carbon fiber-epoxy matrix interphase and its effect on composite mechanical properties

2015 ◽  
Vol 38 (7) ◽  
pp. 1474-1482 ◽  
Author(s):  
Wenzhen Qin ◽  
Frederic Vautard ◽  
Per Askeland ◽  
Junrong Yu ◽  
Lawrence T. Drzal
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Silicon Dioxide ◽  
Epoxy Matrix ◽  
Silicon Dioxide Nanoparticles ◽  
Carbon Fiber Epoxy
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