Background: The irradiation of teeth with a laser results in an interaction between the light and the biological constituents of the dental hard substance, which is converted directly into heat.This thermal effect is the cause of the structural and chemical enamel changes.The combined treatment of topical fluoride agent with laser may increase fluoride uptake, and reduce progression of caries-like lesions. The aim of this study was to measure the uptake of the acidulated phosphate fluoride and sodium fluoride to the buccal and lingual caries-like lesion enamel surfaces before and after irradiated by Nd-YAG laser in comparison with matching control group. Materials and methods: The sample consisted of 30 human healthy upper premolar teeth which were stored in 0.1% thymol solution after extracted. Every tooth divided into: buccal and lingual specimen, each specimen has a rectangular window which was divided to right and left halves (120 specimens). The sample was divided into 2groups (60 specimens) for buccal surface, and the same for lingual surface. The caries-like lesion was formed for all groups except control (1) each group treated with either acidulated phosphate fluoride 1.23% or sodium fluoride 2%, (30 specimens) which contain other subgroups, these are: (10 specimens) one half treated with fluoride agent only and another half as control (first group as control (1) without caries-like lesion, and the second group control (2) with caries-like lesion, then de-ionized water only). (10 specimens) treated with fluoride agent then irradiated by Nd-YAG laser; one half with program (1) (short pulse), andanother with program (2) (long pulse). (10 specimens) irradiated by Nd-YAG laser; one half with program (1) and another with program (2) then treated with fluoride agent. The specimens of enamel were sectioned and the fluoride uptake was determined with using fluoride sensitive electrode. Results: There was a significant difference between the buccal and lingual enamel surfaces regarding the fluoride uptake in sound tooth, while a non- significant difference was observed after artificial caries-like lesion formation. Conclusion: Irradiation of Nd-YAG laser program (1) to the buccal and lingual caries-like lesion surfaces of enamel before application of fluoride agents (APF, NaF) was significantly increase fluoride uptake than that of using laser after the application of fluoride agent, as well as from using laser of program (2) after and before the application of fluoride agent, and from using fluoride agent alone in the buccal and lingual surfaces.
Gypseous soils represented one of the most complex salty soils that faced the geotechnical engineers. Structures that built on gypsum soil will undergo unexpected distortions that will eventually contribute to catastrophic failure. The purpose of this article is to understand the durability of gypsum soil against wetting drying cycles after improvement with polyurethane polymer especially investigate the effect of the wetting-drying cycle on collapsibility. The soil was brought from Sawa lake in AL-Muthanna Governorate in Iraq, with gypsum content 65.5%, A set of Odometer tests were performed to determine the collapsibility potential (CP) for treated and untreated gypsum soil. The result shows that adding a different per
... Show MoreIn this paper the behavior of the quality of the gradient that implemented on an image as a function of noise error is presented. The cross correlation coefficient (ccc) between the derivative of the original image before and after introducing noise error shows dramatic decline compared with the corresponding images before taking derivatives. Mathematical equations have been constructed to control the relation between (ccc) and the noise parameter.
The oxidation desulphurization assisted by ultrasound waves was applied to the desulphurization of heavy naphtha. Hydrogen peroxide and acetic acid were used as oxidants, ultrasound waves as phase dispersion, and activated carbon as solid adsorbent. When the oxidation desulphurization (ODS) process was followed by a solid adsorption step, the performance of overall Sulphur removal was 89% for heavy naphtha at the normal condition of pressure and temperature. The process of (ODS) converts the compounds of Sulphur to sulfoxides/ sulfones, and these oxidizing compounds can be removed by activated carbon to produce fuel with low Sulphur content. The absence of any components (hydrogen peroxide, acetic acid, ultrasound waves and activated car
... Show MoreThe enhancement of heat exchanger performance was investigated using dimpled tubes tested at different Reynolds numbers, in the present work four types of dimpled tubes with a specified configuration manufactured, tested and then compared performance with the smooth tube and other passive techniques performance. Two dimpled arrangements along the tube were investigated, these are inline and staggered at constant pitch ratio X/d=4, the test results showed that Nusselts number (heat transfer) of the staggered array is higher than the inline array by 13%. The effect of different depths of the dimple (14.5 mm and 18.5 mm) has been also investigated; a tube with large dimple diameter enhanced the Nusselts number by about 25% for the ran
... Show MoreChanging oil-wet surfaces toward higher water wettability is of key importance in subsurface engineering applications. This includes petroleum recovery from fractured limestone reservoirs, which are typically mixed or oil-wet, resulting in poor productivity as conventional waterflooding techniques are inefficient. A wettability change toward more water-wet would significantly improve oil displacement efficiency, and thus productivity. Another area where such a wettability shift would be highly beneficial is carbon geo-sequestration, where compressed CO2 is pumped underground for storage. It has recently been identified that more water-wet formations can store more CO2. We thus examined how silica based nanofluids can induce such a wettabil
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