Background: The displacement of artificial teeth during complete denture construction presents major processing errors in the occlusal vertical dimension which were verified at the previous trial denture stage. The aim of this study was to assess the effect of delay in processing after final flask closure and tension application on the vertical acrylic and porcelain teeth displacement of complete dentures constructed from heat cured acrylic and the results were compared with the conventional processing method. Materials and methods: forty samples of identical maxillary complete dentures were constructed from heat polymerized acrylic resin. These samples were subdivided into the following experimental subgroups in which each subgroup contains 5 samples for both acrylic and porcelain teeth and as follows: 1. Conventional flasking technique and immediate processing. 2. Conventional flasking technique and 6 hours delay in processing. 3. flasking technique with tension system and immediate processing. 4. flasking technique with tension system and 6 hours delay in processing. Reference metal pins were attached to the middle of the buccal surface of the upper right canine and center of the buccal groove of the left first molar. And according to these reference points on the teeth another metallic Reference pins were fixed on the denture vestibules and at a distance of 7.5mm by straight lines and 6.5mm where placed between the metal pins and the vestibules in order to standardize the measurement. The distance between the right and left metal pins on the canine and molars and the corresponding metal pins on the buccal vestibules were measured during the wax up stage and after processing by using an optical travelling microscope with an accuracy of 0.0005 mm. Means in (mm) were analyzed statistically by analysis of variance and the comparative T-test and least significance test (LSD). Results: Significant reduction in vertical displacement of the teeth occurred in groups when 6 hours delay in processing were applied, but a significant improvement was also observed in groups with tension system application when compared with control group. On the other hand, there were a high significant reduction in the vertical displacement in groups with tension system and 6 hours delay in processing combination. While for the type of artificial teeth data showed significant difference in the amount of vertical displacement of the teeth in groups with acrylic teeth when compared with porcelain teeth. Conclusions: The findings of this study showed that 6 hours delay in processing and tension system application were effective in reducing the vertical displacement of the artificial teeth during flasking. The maximum reduction in the displacement was observed in dentures constructed from acrylic teeth. On the other hand, significant decrease in vertical displacement of the teeth was detected in dentures constructed from porcelain teeth.
A comparison between the resistance capacity of a single pile excited by two opposite rotary machines embedded in dry and saturated sandy soil was considered experimentally. A small-scale physical model was manufactured to accomplish the experimental work in the laboratory. The physical model consists of: two small motors supplied with eccentric mass 0·012 kg and eccentric distance 20 mm representing the two opposite rotary machines, an aluminum shaft with 20 mm in diameter as the pile, and a steel plate with dimensions of (160 × 160 × 20 mm) as a pile cap. The experimental work was achieved taking the following parameters into consideration, pile embedment depth ratio (L/d; length to diameter) and operating freq
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The study includs,effect of concentration of Lead 0.2 ,0.3 , 0.5, 5 , 10 mg/L and Zinc 0.1,0.5 , 2 , 4 , 8 mg/L lonely or to gether on growth green algae( Scenedesmus quadricauda var . longispina) according to the total qauntity for the cells and the adsorption of the algae to the zn,pb concentration .growth curve and dubbling time growth were calculated with or without there heavy metals . Results shows that there are significant differences (P<0.01) for growth curve and the control. (7.5201 cell /h)and with dubbling times (9.87 cell/h). The heavy metals(Pb, Zn). shows antagonistic effect when both used in media.
The results of studying the effects of M. anisopiliae spores on mosquito, C. quinquefasciatus showed a biological effects represented by immature mortality. The mortality increased proportionally with the concentrations of fungal spores, which reached (at high concentration 2×1011 spores / ml), to 86.6, 56.6% in first and late instar larvae, respectively. An important to mention that cumulative death rate was significantly associated with the time, which reached to 56% at 7 day after treatment. In addition, M. anisopiliae had a long period permanence in aquatic habitats; in which the residual effects stay 30 days in aquatic habitats after treatment at laboratory conditions. Interestingly, the long period exposure of fungal spores (30 minut
... Show MoreThe present study investigated Haematological changes in Mesopotamichthys sharpeyi, as well as determination genotoxic effects of cadmium chloride on bunni fish by using 120 fingerlings, fish were distributed randomly into four treatments in addition to control group. Fish in first group treated (T1) with cadmium 0.093mg/L with changing water and added cadmium continuously, fish in the second group treated (T2) with cadmium 0.093mg/L with changing water without adding cadmium, third treatment (T3) with cadmium 0.046mg/L with changing water and adding cadmium continuously, and fourth treatment (T4) with cadmium 0.046mg/L with changing water without adding cadmium. Results of blood picture in T1 and T3 showed a significant reduction in red bl
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The present study was set to demonstrate the prevalence of toxoplasmosis infection and its effects on patients with systemic lupus erythematosus (SLE) through determining their serum levels of anti-dsDNA and IL-18 antibodies. For this purpose, the sera from 132 SLE and/or toxoplasmosis patients and 30 healthy women, were collected. The study sample was divided into four groups of SLE, toxoplasmosis, SLE coinfected with toxoplasmosis, and healthy control. Anti-Toxoplasma IgG antibodies were examined for all the samples using ELISA kit. The results showed a high mean level of anti-Toxoplasma IgG among SLE patients coinfected with toxoplasmosis (104.8792±12.31585pg/ml) in comparison to that in toxoplasmosis patients (91.1705±12.577
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Wars represent one of the most serious threats to the world order; It is considered a violation of international laws and norms, and humanitarian principles. From this point comes the study of the importance of the topic entitled (The Future of the Russian-Ukrainian war and the extent of its Reflection on the security of Eastern European countries after the year 2022). This study is based on reviewing future possibilities (scenarios) of war. The Russian-Ukrainian war, which was launched by the Russian government led by Russian President Vladimir Putin in February 2022, is still ongoing at the time of writing this research. This chapter includes three possibilities (scenarios). The first possibility deals with the development of the war t
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