Resilient polymeric materials such as silicone elastomers are currently used for maxillofacial prostheses construction but the strength of these materials and their clinical performance need to be optimized with the addition of reinforcing fillers. This study investigates the effect of zirconia nanopowder addition on tear strength, tensile strength, elongation at break, Shore A hardness, surface roughness and cytotoxicity of VST-50 maxillofacial silicone. Silicone base was mixed with different amounts (1%, 2% and 3%) of zirconia nanopowder using a vacuum mixer. Silicone without filler was used as control for comparison. Scanning Electron Microscopy and Atomic Force Microscopy were utilized to assess the efficiency of high-shear vacuum mixing as filler dispersion method and the surface topography, respectively. Both SEM and AFM images showed that the zirconia nanopowder were distributed fairly well within the polymer. Statistically, highly significant increase in tear strength, tensile strength and hardness with non-significant decrease in elongation at break and non-significant increase in surface roughness were seen with 1% and 2% groups. Whereas with 3% group, there was significant improvement in tear strength, tensile strength and hardness but there was significant undesirable decrease in elongation and increase in roughness. Cytotoxicity test revealed that the addition of zirconia nanopowder was nontoxic to Rat Embryonic Fibroblast (REF) cells and there was non-significant change in the cell viability of all study groups after 24- and 72-hours incubation periods. In conclusion, the addition of 2% by weight nano zirconia to VST-50 maxillofacial silicone could be beneficial in enhancing its performance.
Both normally developed insects and insects developed after cessation of eggs growth were
used in this work. Cessation of eggs growth occurred following abnormal conditions, which
lasted for 3.5 months before developing into adults, due to the war led by the U.S. and her
alliances against Iraq. These insects showed low rates of water contents and an active response
to water loss. Therefore their tolerance of desiccation was weak. In addition, they had an active
ability to restore their water loss quickly, after return them to a culture, this indicates that some
changes occurred in their integumentary properties were not permanent and took their turn
within one population only, but may or may not serve this population
Pseudomonas aeruginosa gram-negative, bacilli and facultative aerobic, P. aeruginosa cause cystic fibrosis patients, wounds, burns, and immunodeficienct patients, that have many virulence factors such as pyocyanin , cytotoxic ,biofilm formation and motility, Eighty-eight isolates belonging to P. aeruginosa were collected including the 66 clinical isolates obtained from different hospitals in Baghdad and were from different sources and 22 environmental isolates from previous studies of soil near oil fields. Microscopical and cultural characteristics were studied and diagnosed using biochemical tests, VITEC device, their ability to adhere to non-living (Polystyrene), living cell line (A549) and cytotoxicity of bacterial filtrate
... Show MoreThis study evaluates 22 patients with retained foreign bodies in the maxillofacial region that were all caused by penetrating missile injuries. Surgical intervention for the retrieval of the foreign bodies was carried out in 20 patients through the existing wounds and through separate incisions; all patients were followed up for a minimum of 2 months during which all the complications were registered and managed. Preoperative imaging is a prerequisite for the accurate localization of the foreign body and the subsequent successful removal of it. All patients developed complications that were categorized in this study into those that result from the injury itself and those that occur because of the retrieval procedure, the latter category bei
... Show MoreBackground: Denture fracture is one of the most common problems encountered by the patients and prosthodontists. The objective of present study was to evaluate the transverse strength of nylon denture base resin repaired by using conventional heat polymerized, autopolymerized and visible light cure {VLC} resins, surface treatment that used for repair and adjustment of insufficient nylon denture bases and in case of addition of artificial teeth. As these corrective procedures are common chair side procedures in dental clinic. Materials and methods: One hundred twenty nylon specimens were prepared by using metal patterns with dimension of (65x10x2.5 mm) length, width, and thickness respectively for transverse strength test while for tensile b
... Show MoreThe coupling reaction between tryptamine and 8-hydroxyquinoline led to the formation of a new azo ligand. The synthesized ligand was characterized using CHN, FT-IR, UV-Vis, and NMR spectroscopic techniques. Complexes of the ligand with VO2+, Cr3+, Mn2+, and Mo6+ ions were prepared in a (1:2) ratio, with the general formula [M(L)2]. The obtained complexes were characterized using flame atomic absorption, CHN analysis, FT-IR, and UV-Vis spectroscopy, in addition to magnetic susceptibility and conductivity measurements. The findings suggest that the ligand functions as a bidentate, with the complexes exhibiting octahedral, square planar and square pyramidal geometries. All the complexes were identified as non-electrolytes. Their antioxidant ef
... Show MoreSelf- curing is the potential of lightweight aggregate to absorption great amount of water thru mixing which prominently can moves to the paste during hydration process. Self- curing empowers a water to be distributes more evenly act out the cross section. Whereas, the external curing water is only able to penetrate several millimetres into concrete with low water cement ratio. Brick dust accumulates in the demolish site creates serious environmental contamination. This study investigates the effect of brick dust recovered from construction site on the Properties of mortar cured in three curing conditions. Mortar in this study produced using BD as cement additive with (2, 4, 6, and 8) % by weight of cement. BD was used a
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