Background: Irrigation of the canal system permits removal of residual tissue in the canal anatomy that cannot be reached by instrumentation of the main canals so the aim of this study was to compare and evaluate the efficiency of conventional irrigation system, endoactivator sonic irrigation system,P5 Newtron Satelec passive ultrasonic irrigation and Endovac irrigation system in removing of dentin debris at three levels of root canals and to compare the percentage of dentin debris among the three levels for each irrigation system. Materials and methods: Forty extracted premolars with approximately straight single root canals were randomly distributed into 4 tested groups of 10 teeth each. All canals were prepared with Protaper Universal hand files to size #F4, and irrigated with 2.5% NaOCI 1 ml between files and 5ml for 60 seconds as a final irrigant by different irrigation devices; group one, by using conventional system; group two, by using Endoactivator sonic irrigation system, group three, by using Satelec Passive Ultrasonic irrigation and group four by using the Endovac system. After the final irrigation, the roots were split longitudinally and photographed with a digital microscope. The roots were magnified to 100X; a percentage of debris was calculated for the apical 0-3, middle 3-6 and coronal 6-9 mm. The debris score was calculated as a percentage of the total area of the canal that contained debris as determined by pixels in Adobe PhotoshopCS5. Data were analyzed statistically by ANOVA and LSD at 5% significant level. Results: when comparing the debris remaining, the Endovac, Endoactivator and Satelec groups showed significantly less debris than the conventional group at all three levels (p < 0.01). The Endovac group showed significantly less debris than the Endoactivator group at middle and coronal levels while no significant difference found between the Endovac system and Endoactivator system at apical level. The apical 0-3 mm showed significantly more debris than both the middle and coronal level for all groups. Conclusion: The EndoVac system showed a higher cleaning capacity of the canal at all levels, followed by the protocols that used Endoactivator sonic irrigation system. The conventional irrigation system with maxi-i-probe needles showed inferior results. The apical three millimeters showed a greater amount of debris than the 3-9 millimetres from the working length, regardless of the irrigation device used.
This work presents a computer studying to simulate the charging process of a dust grain immersed in plasma with negative ions. The study based on the discrete charging model. The model was developed to take into account the effect of negative ions on charging process of dust grain.
The model was translated to a numerical calculation by using computer programs. The program of model has been written with FORTRAN programming language to calculate the charging process for a dust particle in plasma with negative ion, the time distribution of a dust charge, number charge equilibrium and charging time for different value of ηe (ratio of number density of electron to number density of positive ion).
The best optimum temperature for the isolate was 30○C while the pH for the maximum mineral removal was 6. The best primary mineral removal was 100mg/L, while the maximum removal for all minerals was obtained after 8 hrs, and the maximum removal efficiency was obtained after 24 hrs. The results have proved that the best aeration for maximum removal was obtained at rotation speed of 150 rpm/ minute. Inoculums of 5ml/ 100ml which contained 106 cell/ ml showed maximum removal for the isolate.
Investment drives the wheel of the development of different developed and developing countries. Sudan is a model for a developing country facing a lot of difficulties in the field of both local and foreign investment. The present study was focused on the problem of poor diversification and efficiency of both local and foreign investment in Sudan. Also, it clarified the important role of administrative supervision to strengthen the efficiency of investment, taking the experience of the Sudan as a model. The researchers used the well-known descriptive and analytical tools (questionnaire, interview, observation) to complete this study. A well designed questionnaire was used. It included all questions that could cover all aspects of
... Show MoreThis research aims at recognizing the concept of Innovation in offering the banking services as well as the concept and dimensions of competitive advantage . And to identify and analyze the relationship ( correlation and impact ) between the concept of Innovation in offering the banking services and the dimensions of the competitive advantage under discussion . The research includes all Iraqi private banks in Baghdad city only of the (20) banks . The researcher adopted , in this study , a random sample of the distribution of the questionnaire to members of the research sample are managers , customers and employees in these banks , and were distributed ( 115 ) form questionnaire , ( 97 ) form w
... Show MoreBackground: The need of the patient for a more reasonable esthetic orthodontic intervention has risen nowadays. Thus, orthodontists make use of esthetic orthodontic materials like brackets, ligature elastics, and arch wires. The esthetic brackets come as different forms of materials, such as ceramic brackets, which have their stainability remaining as the most important consideration for the patients and the orthodontists. This study aimed to compare the staining effects of various staining materials, including black tea, cigarette smoke and Pepsi, as well as the time effect on the color stability of sapphire ceramic brackets bonded with three kinds of light cure orthodontic adhesives: Transbond, Resilience and Enlight. Materials and Met
... Show MoreAbstract:
The internal control is the tool through which it is possible to verify and ensure the implementation of tasks in accordance with the established plans and programs and to evaluate the level of performance that is implemented within the different companies.
A guarantee from the supplier with the absence of a specialized technical committee that follows up the stages of implementing the contract and disbursing all amounts of financial dues to the supplier before completing the implementation of the contract and overlooking the non-implementation of some clauses of the contract by the committee in charge of
... Show MoreBackground: The objective of this in vitro study was to evaluate the vertical marginal fit of crowns fabricated with ZrO2 CAD/CAM, before and after porcelain firing cycles and after glaze cycles. Materials and Methods: An acrylic resin model of a left maxillary first molar was prepared and duplicated to have Nickel-Chromium master die. Ten die stone dies were sent to the CAD/CAM (Amann Girrbach) for crowns fabrication. Marginal gaps along vertical planes were measured at four indentations at the (mid mesial, mid distal, mid buccal, mid palatal) before (Time 0) and after porcelain firing cycles (Time 1) and after glaze cycles (Time 2) using a light microscope at a magnification of ×100. One way ANOVA LSD tests were performed to determine wh
... Show MoreABSTRACT Background: Generally, the facial esthetics depends on the esthetic appearance of the maxillary anterior teeth. The purposes of this study were to analyse the macro-aesthetic appearance of the face and the micro-aesthetic appearance of the maxillary anterior teeth to establish the normative values for class I normal occlusion and to detect possible gender differences. Materials and methods: The sample consisted of 120 Iraqi adults (60 males and 60 females) aged (18-23) years. Each individual was clinically examined, then with cephalostat based head position, extraoral and intraoral photographs were taken for each subject. The facial and dental measurements were measured using AutoCad program 2014. Descriptive statistics was obtaine
... Show MoreIn this work, effects of using different evaporative cooling pads (ECPs) on the energetic and exergetic efficiency of a direct evaporative air cooler (DEAC) have been theoretically and experimentally investigated. Three types of ECPs were used, i.e., honeycomb cellulose cooler pad (HCCP), shading-cloth cooler pad (SCCP), and aspen wood wool cooler pad (AWWCP). For SCCP and AWWCP, a 3-cm pad thickness was used, while for the HCCP, three different values of pad thickness were used, i.e., 3, 5, and 7 cm. Tests were carried out using air velocities of 8, 14, and 19 m/s, measured at the DEAC outlet. Engineering equation solver (EES) used for performing the required calculations of the various parameters affecting the thermal performance of the D
... Show MoreAbstract Software-Defined Networking (commonly referred to as SDN) is a newer paradigm that develops the concept of a software-driven network by separating data and control planes. It can handle the traditional network problems. However, this excellent architecture is subjected to various security threats. One of these issues is the distributed denial of service (DDoS) attack, which is difficult to contain in this kind of software-based network. Several security solutions have been proposed recently to secure SDN against DDoS attacks. This paper aims to analyze and discuss machine learning-based systems for SDN security networks from DDoS attack. The results have indicated that the algorithms for machine learning can be used to detect DDoS
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