Background: Impression materials, impression trays, and poured stone cast have been said to be the main source of cross infection between patients and dentists. However, it was observed that disinfection of the impression is not performed systematically in routine dental practice. Disinfection of alginates either by immersion or spray technique was found to cause dimensional inaccuracies, although with proper disinfection of alginates there were small dimensional changes. A variety of fluoride releasing products designed for topical use is currently available. Following their use, varied amount of fluoride is systemically absorbed depending on the fluoride concentration and the manner of its use. The objective of this study was to evaluate the effect of addition (0%, 0.25%,0.5%,1%, 2%, 3%, 4% ) of (NaF) as a self-disinfection to alginate impression material powder and its effect on setting time, tear strength, dimensional change and accuracy of alginate impression materials. Materials and methods: A total No. of (700) specimen were used in this study.These specimens were divided into (5) main groups according to the tests used. Each of the four main groups contain (70) specimen divided into 7 subgroups (ten specimens to be tested for each (7)concentrations which is composed of six percentages of NaFwith alginate powder (0.25%,0.5%,1%, 2%, 3%, 4% )and one for control (0% NaF) , while the fifth group (Microbiological test) contain 420 specimen were divided between Streptococcus mutans and Candida albicans as (120) specimen for each one that was subdivided into three subgroups (specimens taken before impression casting, specimensafter pouring of alginate with stone andspecimens of stone were taken from the casts) in which it contain the same subgroups of the other concentrationsof (NaF) to test its efficacy against (Streptococcus mutans and Candida albicans). Results: Tear strength for all experimental impression materials was greater than those of the control products. There were no statistically significant differences between the dimensional change tests and also reproduction of detail test.With regard to setting time of the impressions, statisticallyreduction were seen between the control and experimental groups of alginate impression materials that contain (NaF). Self-disinfection of alginate impression material containing NaF showed a significant reduction in the count of cell forming unit of microorganisms immediately after impressions were made. Conclusion: In cooperation of specific concentrations of (NaF) as a disinfectant in alginate dental impression produced a significant reduction of contamination, also they caused non-significant effect on dimensional stability, detail reproduction and significant increase in tear strength. Therefore it is recommended as step in preventing cross contamination. Keywords: Alginate, NaF, Candida Albicans, streptococcus mutans.
Enzymatic hydrolysis process of lignocellulosic biomass materials is difficult because of inherent structural features of biomass, which represents barriers that prevent complete hydrolysis; therefore, pretreatment techniques are necessary to render biomass highly digestible in enzymatic hydrolysis process. In this research, (non?) oxidative short-term lime pretreatment of willow wood was used. A weight of 11.40 g of willow wood was mixed with an excess of calcium hydroxide (0.4 g Ca(OH)2/g raw biomass) and water loading (15 g/g raw biomass). Lime pretreatment was carried out for various periods of time including 1, 2, 3.5, 5 and 6 h, with temperatures at 100, 113, 130, 147 and 1600C, and oxygen pressures as o
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Background: The base of the denture is largely responsible for providing the prosthesis with retention, stability, and support by being closely adapted to the oral mucosa. However; the process of bone resorption is irreversible and may lead to an inadequate fit of the prosthesis; this can be overcome by relining. Materials and methods: Acrylic based soft denture liner is prepared by preparing polymer from purified methylmethacrylate monomer with (10-2) initiator and (30%) dibutylphthalate plasticizer concentrations. Biological properties were evaluated in comparison with the control material through subcutaneous specimens' implantation in the New Zealand rabbits. Excisional biopsies were taken after (1, 3, days 1, 2, 3, 4 weeks) period. Mic
... Show MoreSome of the characters of the Staphylolysin A and D enzymes purified from Pseudomonas aeruginosa P16 and P5 respectively were studied, the molecular weights of Staphylolysin A and D were 20.417 kilo dalton and 23.988 kilo Dalton respectively by SDS- polyacryl amide gel electrophoresis. The optimum pH for staphylolysin A activity was found to be 8 which gives higher activity reaches 150 unit/ml, and for enzyme stability was 7.5-8.5 in which the enzyme nearly retained its full activity, while it was 9.5 for staphylolysin D that gives higher activity of 16 unit/ml,and 8.5-9.5 for enzyme stability in which the enzyme nearly retained its full activity, Maximum activity of two enzymes was obtained at 40C in which the specific activity for st
... Show More(Cu1-x,Agx)2ZnSnSe4 alloys have been fabricated with different Ag content(x=0, 0.1, and 0.2) successfully from their elements. Thin films of these alloys have been deposited on coring glass substrate at room temperature by thermal evaporation technique under vacuum of 10-5Torr with thickness of 800nm and deposition rate of 0.53 nm/sec. Later, films have been annealed in vacuum at (373, and 473)K, for one hour. The crystal structure of fabricated alloys and as deposited thin films had been examined by XRD analysis, which confirms the formation of tetragonal phase in [112] direction, and no secondary phases are founded. The shifting of main polycrystalline peak (112) to lower Bragg’s angle as compared to Cu2ZnSnSe4 angle refers to incorpora
... Show MoreThe effect of approaching nozzle jet from the deposition surface
on structural, optical and morphology properties of copper oxide thin
films was studied. The film was prepared by homemade fully
computerized CNC spray pyrolysis deposition technique at
preparations speed (3, 4, 5, and 6 mm/sec). The repeated line mode
was used at deposition temperature equal 450 °C whereas the
spraying time was in the range of (15-30 min) according to the
deposition speed. The film exhibit polycrystalline structure with
preferred orientation along (-111), (022) and (011), (002) at a 2θ
value of (35.63o) and (38.8o) respectively. Optical band gaps were
recorded at these speed shows variance in value from (1.53-2.08 eV).
Fi
The purpose of this work is to clarify the effect of the Active Galactic Nucleus (AGN) on the properties of the galaxy. A photometric study of two galaxies by surface optical measurements techniques and by using'griz filters' was performed. The scientific material that used in this work was obtained from ''SLOAN DIGITAL SKY SURVEY'' (DR7), a fuzzy color, contour maps, photometric parameters, and color indices were studied by using surface photometric technique. The work was done by Ellipse task in IRAF (Image Reduction and Analysis Facility) software from the National Optical Astronomy Observatory (NOAO).
Spray pyrolysis technique was subjected to synthesized (SnO2)1-x (TiO2: CuO) x Thin films on different substrates like glass and single crystal silicon using. The structure of the deposited films was studied using x-ray diffraction. A more pronounced diffraction peaks of SnO2 while no peaks of (CuO , TiO2 ) phase appear in the X-ray profiles by increasing of the content of (TiO2 , CuO) in the sprayed films. Mixing concentration (TiO2 , CuO) influences on the size of the crystallites of the SnO2 films ,the size of crystallites of the spray paralyzed oxide films change in regular manner by increasing of (TiO
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