Background: Limited data are available on the dimensional stability and surface roughness of ThermoSens, which is a material used in denture processing. This study aimed to measure the vertical teeth changes and surface roughness of ThermoSens dentures prepared using three different investment materials. Materials and methods: For the dimensional changes test, 30 complete maxillary dentures were prepared using different investment methods: group I, dental stone; group II, silicone putty; and group III, a mixture of dental stone and plaster (ratio, 1:1; n = 10 for each group). Four screws were attached to the dentures: two were attached to the buccal surface of the canine and first molar, and the other two were attached in the flange areas of the canine and first molar in line with the previously mentioned screws. Measurements were made using a micrometer microscope in the wax stage before flasking and in the deflasking stage. The above investment techniques were also used to prepare samples for a surface roughness test (n = 10 per group). These samples were prepared according to the specifications of the American Dental Association. Data were examined using analysis of variance (ANOVA) and the least significant difference (LSD) test. Results: One-way ANOVA and LSD revealed that dimensional changes significantly differed among all groups, except that the vertical teeth changes on the left side did not differ between groups I and II for both the canine and molar regions. Surface roughness was significantly higher in group I than in group II, and in group III than in group II. Conclusion: The use of putty silicone for investing ThermoSens complete dentures reduced dimensional changes and resulted in dentures with a better fit. Surface roughness could be reduced by the addition of a putty silicone layer over the denture before the addition of the second investment layer during denture processing.
The experiment was conducted at the faculty of agriculture University of Ain Shams-Egypt, from January to March 2008, to study the effect of different levels of chromium yeast (cr-yeast) on broiler chickens on some physiological traits. A total of 450, one-day old unsexed chickens (Cobb) strain were used. The birds were randomly allocated to five treatments with 3 replicates each. The treatments were control (T1), without supplementation, T2, T3, T4 and T5 which were supplemented with 0.5, 1, 1.5 and 2 mg cr-yeast/kg diet respectively. Chromium yeast supplementation treatments caused a significant (p < 0.05) increase in plasma glucose levels, while supplemented Cr-yeast at levels of 1 (T3), 1.5 (T4), 2 (T5) mg/kg diet resulted in a signific
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A numerical method (F.E.)was derived for incompressible viscoelastic materials, the aging and
environmental phenomena especially the temperature effect was considered in this method. A
treatment of incompressibility was made for all permissible values of poisons ratio. A
mechanical model represents the incompressible viscoelastic materials and so the properties can
be derived using the Laplace transformations technique .A comparison was made with the other
methods interested with viscoelastic materials by applying the method on a cylinder of viscoelastic material surrounding by a steel casing and subjected to a constant internal pressure, as well as a comparison with another viscoelastic method and for Asphalt Concrete pro
In this study, nanoparticles were synthesized using the pulsed laser ablation technique, employing an Nd:YAG laser with a wavelength of 1064 nm. The ablation process was carried out at room temperature under varying laser energy of 950 mJ. The structural characteristics of the resulting nanoparticles were investigated using X-ray diffraction (XRD) and atomic force microscopy (AFM). The biological impact of the synthesized nanoparticles was assessed by administering two different doses (1 ml/kg and 4 ml/kg) to experimental animal models. The study evaluated changes in thyroid hormone levels, specifically thyroid-stimulating hormone (TSH), triiodothyronine (T[Formula: see text] and thyroxine (T[Formula: see text]
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Carbon tetrachloride (CCl4) has been demonstrated to induce testicular damage via oxidative stress. Bromelain (Br), a proteolytic enzyme known for its biological activities and pharmacological properties, exhibits limited absorption owing to its low solubility and bioavailability. The present study aimed to investigate the histological and immunohistochemical effects of bromelain conjugated with gold nanoparticles (AuNPs) on the testis histology of albino mice treated with CCl4. Thirty-five male albino mice (Mus musculus), with an average age of 9 weeks, were randomly divided into five groups, each containing seven mice. The experiment was prolonged for four weeks. The first group (G1) was the control group, the second group (G2) re
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This study was carried out to determine the effects of NaCl (0.00, 50, 100, 150, 180 or 200) mM and two different types of mutagens chemical mutagen ethyl methyl sulphonate (EMS) at 0.5% and physical mutagen UV-B irradiation (40 min time exposure), on mitotic division in two Iraqi rice genotypes Amber 33 (A33) and Amber Baghdad (AB). Different concentrations of NaCl were used. Mitotic index (MI %) was decreased significantly by increasing NaCl concentration, however the highest mitotic index was recorded in mutated genotypes with EMS and UV-B. Different abnormal chromosomes were noticed in mutated plants. Results showed high percentage of abnormal chromosomes in EMS mutated genotypes. In addition no significant differences between genotypes
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The zirconia ceramic restoration (ZCR) is used as substitutes for the metal-ceramic restoration. Clinical studies demonstrating of ZCRs showed a high fracture incidence of veneering layer than metal-ceramic restorations. This attributed to the low bond strength of zirconia to veneering ceramic as a result of lacking of glass content in its matrix. Surface treatment was proposed to improve the bonding strength between zirconia and veneering ceramic. Several studies revealed that some treatment such as airborne particle abrasion (APA) is responsible for generating chipping of veneering ceramic. The study aimed to develop a new zirconia coatings to increase bonding strength between zirconia substrate and veneering porcelain. Three groups of 15
... Show MoreLaser drilling is capable of producing small, precisely positioned holes with high degree of reproductively. In this paper , IR millisecond Nd:YAG single pulsed laser was used to determine the effect of laser parameters on the drilled hole of the glass - fiber reinforced epoxy composite FR-4 sample of 2 mm in thickness . The type of laser source was GSI lumonics JK760TR Series laser 1.064μm system in a CNC cabin. The JK760TR series has a 0.3-50ms pulse length and a maximum repetition rate 500Hz with an average power of 600W. The investigation of single pulse laser drilling in this paper was based on theoretical and experimental solutions. In single pulse technique, the investigation included focal plane position fpp, pulse shap
... Show MoreThis research aims to investigate and evaluate a reactive powder concrete (RPC) cast using economical materials. Its mechanical properties were investigated and evaluated by studying the effects of using different cement and silica fume contents and locally steel fibers aspect ratios as reinforcement for this concrete. A compressive strength of about 155.2MPa, indirect tensile strength of 16.0MPa, modulus of elasticity of 48.7GPa, flexural strength of 43.5MPa, impact energy of 3294.4kN.m and abrasion loss 0.59% have been achieved for reinforced RPC contains 910 kg/m3 cement content, silica fume content 185 kg/m3 of cement weight and fiber volume fraction 2%. The water absorption values w
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