Background: The fracture of instruments within root canal during endodontic treatment is a common incidence, fracture because of fatigue through flexure occurs due to metal fatigue, this study aimed to assess the effect of curvature angle and rotational speed on the cyclic fatigue of different type of Endodontic NiTi Rotary Instruments and compare among them. Materials and method: Three types of rotary instruments with tip size 0.25: ProTaPer F2 (Densply, Malifier) Revo-S SU( 0.06 taper, MicroMega) and RaCe system (0.06 taper, FKG, Dentaire), Forty file of each instrument were used within two canals with angle of curvature (40 &60 )at two speed (250&400)RPM, twelve group were formed for all instruments(total number=120),ten file for each group. The testing canals customized within stainless steel block covered with glass face, the time to fracture recorded and the mean of cycles to fracture (MCF) detected for each instrument. Data were analyzed statistically by ANOVA, LSD and Independent T-test at 5% significant level. Result: there was a highly significant difference of curvature angle and significant difference of rotational speed on the fracture resistance of instruments. RaCe revealed the best fracture resistance followed by ProTaper then Revo-S that showed the less resistance. Conclusion: The rotary instruments more prone to fracture when used at more curvature angle and higher rotational speed, as well as the rotary instruments differ from each other according to manufacturing process, taper, cross section and other factors.
Back ground: This in vitro study was carried out to investigate the effect of post space regions (coronal, middle and apical), Time and the mode of polymerization (dual, self-cured) of the cements used on the bond strength between translucent fiber post and root dentin by using push-out test. Materials and Methods: Forty eight extracted mandibular first premolars (single root) were instrumented with ProTaper Universal system files (for hand use) and obturated with gutta percha for ProTaper and AH26® root canal sealer following the manufacturer instructions, after 24 hours post space was prepared using FRC postec® plus drills no.3 creating 8 mm depth post space. The prepared samples were randomly divided into two main groups (24 samples ea
... Show MoreObjectives: The main objective of this study is to examine the crucial role that Russian writers and intellectuals played in catalyzing the 1905 Revolution in Russia. Specifically, the study sought to analyze how their literary works, philosophical ideas, and political writings challenged Tsarist autocracy, depicted the suffering of the masses, and inspired opposition movements. The study aimed to highlight the defiant writings that contributed to the rise of political figures and the eventual overthrow of the repressive regime. Methods: The historical narrative and analytical methods were employed, conducting a comparative analysis of prominent works by renowned authors such as Tolstoy, Gorky, and Chekhov. This analysis focused on
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IH Abdul-Abbas, QJ Rashid, M RasimYounus, PalArch's Journal of Archaeology of Egypt/Egyptology, 2021 - Cited by 9
Histological study of the cerebellum in a bird white cheeked bulbul Pycnonotus lecucotis, the result of the study showed that the cerebellum took the parts of the hindbrain, the histological study of the cerebellum revealed the presence of deep folds on its surface. The cerebellum consists of two areas, the cerebellar cortex, which is called the gray matter, which consists of three layers: the outer layer (the molecular layer), the middle (Purkinje cells) and inner layer (the granular layer). The second area of the cerebellum is called the medullary and the white matter.
هدف البحث التعرف الى اسباب سلوك التنمر لدى طلاب الصف الاول المتوسط من وجهة نظر المدرسين والمدرسات واساليب تعديله، واستعمل الباحثان المنهج الوصفي واختيار عينة عشوائية من المدرسين والمدرسات في متوسطة أرض الرافدين ومتوسطة الرحمن للبنين وكان عددهم (46) مدرساً ومدرسة بواقع (32) مدرساً و(14) مدرسة، واعتمد الباحثان الاستبانة أداة للتعرف الى اسباب سلوك التنمر واساليب تعديله، واشارت نتائج البحث الى تنوع اسباب التن
... Show MoreA legal discourse in the Qur’an and Sunnah is almost devoid of the use of one of the general formulas, and due to its frequent rotation in the tongue of the legislator, the formulas may overlap their members in apparently contradictory provisions, which makes the individual from the general members appear to the beholder to be covered by two contradictory provisions, and this research came to present what might happen to him The legal text interpreter of weighting between the two opposing texts is the strength of the generality that is established by the generality formula, so the two strongest formulas in the inclusion of its members outweigh the weaker of them and precede them, and the research decided that the formulas vary
... Show MoreThis study aimed to show the extent of compliance with the income taxpayer to provide tax returns and increase the speed of collection of these taxes in addition to increasing confidence in Income Tax department and reduce the number of cases transferred to the courts and promote taxpayer awareness in charge of the importance of self-assessment system, and study sought to investigate the effect of the existence of records documents, technical audit, and computational audit and documentary audit on income tax collections in Jordan, from the point of viewof Jordanian income tax auditors ,results shows there's a strong relation between these variables and Income Tax collections.
The aim of this research is to find the impact of the efficiency of Management information systems (MIS) on the effectiveness of governmental organizations performance.
To achieve the objective of the research, the analytical descriptive method was adopted. A questionnaire was designed consisting of (35) paragraphs, and the sample consisted of (200) individual. The research attemped to answer the following question: To achieve the objective of the research, the analytical descriptive method was adopted. A questionnaire was designed consisting of (35) paragraphs, and the sample consisted of (200) individual. The research tried to answer the following question: What is the actual utilization of modern admi
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