Background: White-spot lesion is one of the problems associated with the fixed orthodontic treatment. The aims of this in-vitro study were to investigate enamel damage depth on adhesive removal when the adhesive were surrounded by sound, demineralized or demineralized enamel that had been re-mineralized prior to adhesive removal using 10% Nano-Hydroxy apatite and to determine the effect of three different adhesive removal techniques. Materials and methods: Composite resin adhesive (3M Unitek) was bonded to 60 human upper premolars teeth which were randomly divided in to three groups each containing ten sound teeth and ten teeth with demineralized and re-mineralized lesions adjacent to the adhesive. A window of 2 mm was prepared on the buccal surface of the tooth and painted with an acid resistant nail varnish except for the window.The demineralized enamel produced by immersion of teeth in demineralization buffer for 12 days.half of the demineralized window, was covered with acid –resistant red nail varnish, and the samples were then subjected to re-mineralization with 10% of nano hydroxyapatite. The adhesive was removed with either :(1) fiber reinforced composite bur in slow speed handpiece (SS); (2)12 fluted long flame carbide bur in high speed handpiece (HS); (3) ultrasonic scaler (US).damage to the enamel was assessed using stereomicroscope with grid eye piece. Results: the greatest to least mean depth of damage with three different adhesive removal techniques to sound enamel was HS˃ US ˃SS and to demineralized and re-mineralized enamel were SS ˃US˃ HS. Sound enamel had the least amount of damage. Re mineralization before the adhesive removal highly significant reduced the amount of damage produced by all techniques compared with demineralized enamel. Conclusions: When the demineralized enamel was present 12 fluted long flame carbide bur were found to be the least damage in adhesive removal technique and re-mineralization further reduced the amount of enamel damage
The physical, mechanical, electrical and thermal properties containing (Viscosity, curing, adhesion force, Tensile strength, Lap shear strength, Resistively, Electrical conductivity and flammability) of adhesive material that prepared from Nitrocellulose reinforced with graphite particles and aluminum streat. A comparison is made between the properties of adhesive material with varying percentage of graphite powder (0%, 25%, 30%, 35%, 40%) to find out the effect of reinforcement on the adhesive material. The ability of property an electrical was studied through the measurement of conductivity a function of temperature varying. The results of comparison have clearly shown that the increasing of conten
... Show MoreThe aim of this paper is to compare between classical and fuzzy filters for removing different types of noise in gray scale images. The processing used consists of three steps. First, different types of noise are added to the original image to produce a noisy image (with different noise ratios). Second, classical and fuzzy filters are used to filter the noisy image. Finally, comparing between resulting images depending on a quantitative measure called Peak Signal-to-Noise Ratio (PSNR) to determine the best filter in each case.
The image used in this paper is a 512 * 512 pixel and the size of all filters is a square window of size 3*3. Results indicate that fuzzy filters achieve varying successes in noise reduction in image compared to
Light has already becomes a popular means of communication, and the high-bandwidth data into free space without the use of wires. A great idea took us to design a new system for transmitting sound through free space at (650, 532) nm wavelengths using reflective mirrors under different atmospheric conditions. The study showed us the effect of various weather factors (temperature, wind speed and humidity) on these wavelengths for different distances. As well as studying the attenuation caused by long-distance laser and beam divergence, A reflective dish was used to focus the spot of the laser beam on the photocell. Results were discussed under the effect of these factors and the attenuation resulting from the beam divergence. Thus, the sys
... Show MoreThe dynamic thermomechanical properties, sealing ability, and voids formation of an experimental obturation hydroxyapatite-reinforced polyethylene (HA/PE) composite/carrier system were investigated and compared with those of a commercial system [GuttaCore (GC)]. The HA/PE system was specifically designed using a melt-extrusion process. The viscoelastic properties of HA/PE were determined using a dynamic thermomechanical analyser. Human single-rooted teeth were endodontically instrumented and obturated using HA/PE or GC systems, and then sealing ability was assessed using a fluid filtration system. In addition, micro-computed tomography (μCT) was used to quantify apparent voids within the root-canal space. The data were statistically analys
... Show MoreFive bread wheat cultivars was selected namely, IPA99, Tamouz 2, Rasheed, Abu-ghraib And Iraq, were selected for susceptibility to green bug, Schizaphis graminum R.(Aphididae: Homoptera) infestation. Experiments done in under laboratory temperature 20±2C˚, humidity 65±5 % at 12h light. Results have indicated that IPA99 was highly preferred by in S. graminum and no significant of differences with Rasheed and Abu-ghraib, while Iraq and Tamouz2 came second. Although all wheat cultivars were infested by S. graminum except Iraq cultivar which showed some tolerance when exposed to three densities of 5, 10, ap plant during the time of test was 4 weeks. the development time of nymphs were 8, 8, 9, 9.3and 8.3 days for cultivars IPA99, Tamoz2,
... Show MoreAbstract
Praise be to Allah and prayers and peace be upon our Prophet, Muhammad, his family and all of his companions,
This research addresses the issue of judge's preaching to the litigants and witnesses; it is a very significant issue since the judge cannot know the insides and facts, but it issues judgments based on the hearings. Since people are originally wrong-doing and ignorant, they, therefore, commit injustice, oppression, false adversarial, and false testimony. However, some people can possibly retreat and return to the right, after being inattentive or recalcitrant, by preaching. This fact led scholars to talk about the judge's preaching to litigant and witnesses and this research is conducted
... Show MoreThe study included adding antimony oxide to mixtures of coating metal surfaces (Enameling), after it was selected ceramic materials used in the coating metal pieces of the type of steel and cast iron in two layers. The first is called a ground coat and the second is a cover coat.
Ceramic materials layer for ground coat have been melted down in
platinum crucible at a temperature of 1200oC to prepare the glass
mixture (Frit). It was coated on metals at a temperature of 780oC for
two minutes, while the second layer was prepared glass mixture
(Frit) at a temperature of 1200oC, but was coated at a temperature of
760oC for two minutes.
Underwent tests crystalline state of powders (Frits) and enameled samples using X-ray di
The metformin drug is anti-hyperglycemia and known to cross the placenta which leads to the fetus during pregnancy .The aim of this study is to define the drug effects in the fetus growth . The doses used , therapeutic dose ( 0.18 & 0.53 ) mg\25g body weight and over dose ( 1.8 & 2.85) mg\ 25g body weight , administrated orally at the beginning organogenesis stage at ( 6 -18 ) day of pregnancy in the morning . A total ( 50 ) animal were divided into five groups .The first group control not treated , 2nd group treated with (0.18) mg , 3rd group with ( 0.53 ) mg , 4th group with ( 1.8 ) mg and 5th group
... Show MorePolyacrylamide Solutions of different concentrations (0.2, 0.4, 0.6, 0.8, 1.0 %) of Ag nanoparticles and ZnO nanoparticles were prepared, the viscosities and surface tension were measured for all solutions, where measurements indicated an increase in these properties with increased concentration, where the relative viscosity of polyacrylamide/zinc nanoparticles increased from 1.275 to 2.243, and the relative viscosity of polyacrylamide/silver nanoparticles increased from 1.178 to 1.934. Viscosity is significant parameters during electrospinning process. While the surface tension of the polyacrylamide/zinc nanoparticles has changed from 0.0343 Nm-1 to .0.0.0 Nm-1 and changed from .0.000Nm-1 to.0.0.0 Nm-1. Also the constants KH and KK were
... Show MoreThis research includes a study of the effect of four temperatures (25, 30, 35, 40m◦) with relative humidity 65% on some biological aspects of the Bean beetle Acanthoselides obtectus on the Bean seeds under laboratory conditions. The results showed that the effect of different temperatures is clear on biological of Bean beetle. Differed period necessary for the growth and development of each stage of the insect in different temperatures . The results of statically analysis showed a significant difference in the life cycle when all temperatures except the period between temperature 35 and 40m◦ , respectively. Where the average of those period, 60.75, 35.5, 20.34 and 19.27 days and also different temperatures significant effects is clea
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