Soaking dentures with disinfection solutions is an effective way of keeping dentures in a healthy status; however, immersions in these solutions have a negative effect on the bond strength of denture base and denture teeth. The aim of this study was to evaluate the bond strength between denture acrylic teeth and heat-cured Poly (methyl methacrylate) denture base material (with and without nano silica) after disinfection with different chemical disinfectants for a simulated period of six months. One hundred specimens of maxillary central incisors attached to PMMA were divided into two groups; 50 specimens of PMMA without nano silica and 50 specimens of PMMA reinforced with 5 wt% of nano silica. Specimens of each group were immersed in five immersion solutions (n=10): distal water (control), Fittydent® cleansing tablets, 4% chlorohexidine, 1% sodium hypochlorite and Dettol personal care solution. Bond strength were carried out in a universal testing machine with crosshead speed of 0.5 mm/min. Data analysis was done using independent sample t-test, one-way ANOVA and Tukey’s HSD post hoc test. Results showed that bond strength increased significantly in nano silica groups compared to groups without nano silica. Bond strength decreased in all immersion groups, for both groups of PMMA, but the Dettol group showed the least significant decrease (P>0.05). Reinforcing PMMA denture base with nano silica increased the bond strength with acrylic teeth. Denture tablets, chlorohexidine and sodium hypochlorite decreased the bond strength significantly, while Dettol personal care solution did not significantly reduce bond strength.
Mortar of ordinary Portland cement was blended with cockles shell
powder at different weight ratios to investigate the effect of powder
admixture on their strength and thermal conductivity. Results showed
that addition of cockles shell powder at 50% of mortar weight
improves hardness and compressive strength notably and reduces the
thermal conductivity of the end product. Results suggest the
possibility to incorporate cockles shell powders as constituents in
cement mortars for construction and plastering applications.
In this paper, chip and powder copper are used as reinforcing phase in polyester matrix to form composites. Mechanical properties such as flexural strength and impact test of polymer reinforcement copper (powder and chip) were done, the maximum flexural strength for the polymer reinforcement with copper (powder and chip) are (85.13 Mpa) and (50.08 Mpa) respectively was obtained, while the maximum observation energy of the impact test for the polymer reinforcement with copper (powder and chip) are (0.85 J) and (0.4 J) respectively
A new ligand (H4L) and its complexes with ( ZnII, CdII and HgII) were prepared. This ligand was prepared in two steps. In the first step a solution of terephthaldehyde in methanol was reacted under reflux with 1,2-phenylenediamine to give an precursor compound which reacted in the second step with 2,4-dihydroxybenzaldehyde to give the ligand. The complexes were then synthesized by direct reaction of the corresponding metal chloride with the ligand. The ligand and complexes were characterized by spectroscopic methods FT-IR, UV-Vis, 1 HNMR, and atomic absorption, chloride content, HPLC, mole-ratio determination. in addition to conductivity measurement. The data of these measurements suggest a distorted tetrahedral geometry for ZnII, C
... Show MoreA new ligand (H4L) and its complexes with ( ZnII, CdII and HgII) were prepared. This ligand was prepared in two steps. In the first step a solution of terephthaldehyde in methanol was reacted under reflux with 1,2-phenylenediamine to give an precursor compound which reacted in the second step with 2,4-dihydroxybenzaldehyde to give the ligand. The complexes were then synthesized by direct reaction of the corresponding metal chloride with the ligand. The ligand and complexes were characterized by spectroscopic methods FT-IR, UV-Vis, 1HNMR, and atomic absorption, chloride content, HPLC, mole-ratio determination. in addition to conductivity measurement. The data of these measurements suggest a distorted tetrahedral g
... Show MoreThe prostheses sockets use normally composite materials which means that their applications may be related with the human body. Therefore, it was very necessary to improve the mechanical properties of these materials. The prosthetic sockets are subjected to varying stresses in gait cycle scenario which may cause a fatigue damage. Therefore, it is necessary or this work to modify the fatigue behavior of the materials used for manufacturing the prostheses sockets. In this work, different Nano particle materials are used to modify the mechanical properties of the composite materials, and increase the fatigue strength. By using an experimental technique, the effect of using different volu
Joint diseases, such as osteoarthritis, induce pain and loss of mobility to millions of people around the world. Current clinical methods for the diagnosis of osteoarthritis include X-ray, magnetic resonance imaging, and arthroscopy. These methods may be insensitive to the earliest signs of osteoarthritis. This study investigates a new procedure that was developed and validated numerically for use in the evaluation of cartilage quality. This finite element model of the human articular cartilage could be helpful in providing insight into mechanisms of injury, effects of treatment, and the role of mechanical factors in degenerative
conditions, this three-dimensional finite element model is a useful tool for understanding of the stress d
Aluminum oxide (ALO) was grafted by acrylic acid monomer (AlO-AM) and then, it was polymerized to produce alumina grafted poly(acrylic acid) (AlO-AP). The prepared AlO-AM and AlO-AP were characterized by Fourier-transform infrared, differential scanning calorimetry , thermogravemetric analyzer and particle size distribution. Adsorption equilibrium isotherms, adsorption kinetics and thermodynamic studies of the batch adsorption process were used to examine the fundamental adsorption properties of phenol (P) and p-chlorophenol (PCP). The experimental equilibrium adsorption data were analyzed by three widely used two-parameters Langmuir, Freundlich and DubininRadushkevich isotherms. The maximum P and PCP adsorption capacities based on t
... Show MoreStudy the effect of additives polymer polyvinyl alcohol (PVA) after solving in water by concentration 10% since represent a standard of PVA solution with added to cement – silica composite of ratio (1:2) with 5%, 10%, 15%, 20%, and 25% respectively to the standard quantity of water which using as a mortar of building. The results are demonstrate increasing on compression resistance with increase of PVA solution until 20%, and decreasing of thermal conductivity which represent a composite are increasing in thermal insulating. The results were recommended decreasing of water absorption with increase of PVA solution ratio as illustrated in this study.
A novel mixed natural coagulant has been developed to remove sewage pollutants and heavy metals from Qanat- al- Jayesh by using low cost adsorbent natural materials. In these materials, significant interaction contains Arabic gum mixed with extracted silica from rice husk ash (natural coagulants) by the Batch device approach, using two variables, pH values ranging from 5-8 and contact times between 0.25-5 hrs. All wastewater samples were collected after treatment by adsorbents and examined for determination of residual heavy metal concentrations: Pb, Ni, Zn and Cu by atomic absorption spectroscopy (AAS), turbidity, pH, total dissolved salts (TDS), electrical conductivity (EC) and total salinity (TS). The results obtained indicate Th
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