Background: The accuracy of fitness of any dental casting is imperative for the success of any prosthodontic treatment. From the time that dental casting was first introduced, efforts have been made to produce more accurate and better fitted castings with minimal marginal discrepancy. The aim of this in vitro study was to evaluate the effects of three different investing and burnout techniques on the vertical marginal discrepancies ofceramometalcopings invested with two types of phosphate- bonded investments. Materials and methods: Sixty wax patterns were fabricated on a standardized prepared brass die representing an upper central incisor by the aid of a custom-made split mold. Three different investing and burnout techniques were applied for an Iraqi investment and a commercial type; Group I:Ring investing with conventional burnout technique (RC);Group II: Ringless investing with conventional burnout technique (RLC);Group III: Ring investing with accelerated burnout technique (RA).Twenty wax patterns of each group were divided into two subgroups according to the type of investment material used (10 for each subgroup) represented as (B) for the BellaStar XL and (W) for the WYMvest investments. Complete castings were finished and seated on the metal die. The accuracy of fit of each coping was determined by measuring the vertical marginal discrepancies between the finish line on the metal die and the margins of each coping at four specific reference points on the labial, mesial, palatal, and distal aspects of the die by the aid of a light microscope supplied with a digital camera.The arithmetic mean of each three records was computed and regarded as the amount of the marginal discrepancy of each coping and was used as a unit for the statistical analysis. Results: Mean marginal accuracy for W(RLC)was found to be the least (13.839+4.5724 um) while the highest mean value related to B(RLC) (29.033+2.102 um). In general, ANOVA test showed significant results among the mean values of the Binvestment subgroups while LSD test showed non-significance between the (RA) and both the (RC) and (RLC) subgroups. On the other hand, significance was present between the (RLC) and (RA)of the Winvestment subgroups while non-significance was located between the (RC) and both the (RLC) and (RA) subgroups. Comparing similar subgroups of the two tested investments, the Student's t-test showed non-significance between the (RC) subgroups while high significance was located between the (RLC) and (RA) subgroups respectively.Concerning the vertical marginal discrepancy of the copings, applying the (RC) technique for both investments caused non-statistical significance between the labial, mesial, palatal, and distal aspects.The (RLC) technique caused high significance between the four aspects, while the (RA) technique caused non-significance between the labial aspect only and the others. Conclusion: The Iraqi investment generally produced less vertical marginal discrepancies (using the three different investing and burn-out techniques) than the commercial investment.In order to achieve a better marginal fit, it seems that ceramometalcopings invested with the commercial investment tested are better be cast using the conventional ring investing and burnout technique.
The reclamation of makeup water is studied in terms of breakthrough time (i.e., the leakage of the cations). Makeup water was subjected to lab-scale ion exchangers of two types: strong acid cation and weak base anion exchanger. The experimental investigation was directed to study the ion exchanger performance in terms of four different parameters (i.e., copper concentration, total dissolved solids (TDS), feed rate and bed depth). Box-Wilson composite rotatable design was adopted in designing the experiments. Breakthrough times of the effluent stream are measured in terms of copper concentration of 2 to 25 ppm, TDS concentration of 250 to 1250 ppm, feed rate of 0.38 to 5.34 l/h and bed depth of 5 to 70 cm. Simulation the effect of the stu
... Show MoreA survey of chrysidid wasps and an identification key to the genera from different localities in Iraq are provided. The genus Pseudomalus Ashmead, 1902 with Pseudomalus auratus (Linnaeus) and Omalus timidus (Nurse), are new records from Iraq. As well, a preliminary checklist of Iraq’s Chrysididae is suggested. Twenty species within nine genera in two subfamilies have been included in the current list. Historical information is provided together with remarks on the current taxonomic status and the particular validity for some species.
drosophila larvare of diffrent speces were subjected to this in order study the structure of cephalopharyngeal armature and mouth more hooks dentition the lines number among
With the emergence of globalization, international and diplomatic relations have developed among countries and led to the creation of new words, concepts and diplomatic terminology. The purpose of this thesis is to study and analyze the types of written, oral and nonverbal diplomatic language and to shed light on the types of diplomatic translation/interpretation. In addition to that, the thesis investigates the role of translator/interpreter when translating diplomatic texts and interpreting diplomatic speeches in international conferences, organizations, etc. It also tackles the difficulties faced during translation/interpretation and how to overcome these problems and find appropriate solutions for them. The main purpose of this thesi
... Show MoreIn this study, we came across various concepts in the three major Gokturk inscriptions, namely Kul Tigin, Bilge Kagan and Tunyukuk. We classified these concepts under 33 main headings such as “proper names, geography, cities, tribe, descriptive names, colors, language materials, time, plants, animals, humans, kinship, titles and ranks, professions, identity, bodun, number, politics, trade, art, wealth and poverty, religion and belief, ceremony” etc. In our study, we only considered the words that constitute nouns. While preparing the conceptual index, we divided a large part of these 33 main headings into various subheadings. We listed the words alphabetically. Since we detected different meanings of some of the headings in our index, w
... Show MoreA flight simulation programme has been developed on a personal computer using Microsoft
FORTRAN to simulate flight trajectories of a light aircraft by using Six-Degree-of-Freedom
equation of motion. The simulation has been made realistic through pre-programmed the input to
the control surfaces, atmospheric gust during the flight mode. The programme plays an important
role in the evaluation and validation of the aircraft design process. A light aircraft (Cessna 182T)
has been tested through free flight, gliding flight, flight with gust. The results show good trend and
show that the programme could be dependent as a realistic flight test programme.
The protection of the rights of minorities is primarily an internal issue that depends on the nature of the political system of the state, and it is one of the internal means to reassure minorities and ensure their enjoyment of those rights. It can be a safety valve against the problems that these minorities may raise. that live in our society, but rather work on developing a legal system that can serve as a role model to protect our minorities, which contributed to drawing a picture that reflected the diversity of our society
The current research aims to identify the self-regulation of university students, as well as to identify the significance of the difference in self-regulation according to the variable of sex (male-female), specialization (scientific-human), and grade (first-fourth). To achieve the research objectives, the two researchers developed a scale of (28) items about self-regulation According to the theory of (Pandora, 1991). The scale was administered to (500) students from the first and fourth stages of Al -Mustansiriyah University who were selected based on the random stratification method for the 2020/2021 academic year. The results showed that university students have a good level of self-regulation. There are no significant differences in
... Show MoreContinuous functions are novel concepts in topology. Many topologists contributed to the theory of continuous functions in topology. The present authors continued the study on continuous functions by utilizing the concept of gpα-closed sets in topology and introduced the concepts of weakly, subweakly and almost continuous functions. Further, the properties of these functions are established.