Objectives To tailor composites of polyethylene–hydroxyapatite to function as a new intracanal post for the restoration of endodontically treated teeth (ETT). Methods Silanated hydroxyapatite (HA) and zirconium dioxide (ZrO2) filled low-density polyethylene (LDPE) composites were fabricated by a melt extrusion process and characterised using infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The flexural strength and modulus were determined in dry state and post ageing in simulated body fluid and fractured surfaces analysed by SEM. The water uptake and radiographic appearance of the experimental composites were also measured and compared with a commercially known endodontic fibre post. Data were submitted to one-way analysis of variance (ANOVA) and post hoc Tukey multiple comparison tests at a level of significance P < 0.05. Results The LDPE/HA composites were structurally flexible and the HA content had a significant effect on the flexural strength and modulus. A univariate analysis of variance showed no significant differences in modulus and strength (P < 0.05) post accelerated ageing in simulated body fluid with very low water uptake. The melting point of the LDPE/HA composites ranged between 135 and 136 °C, which would facilitate removal in case of retreatment using conventional dental heating devices. The inclusion of HA reduced the damping thereby enhancing dimensional stability, whilst the addition of zirconia yielded a semi-translucent material that was sufficiently radiopaque, comparable to commercial posts, thus yielding aesthetic materials. Conclusions Innovative materials for restoration of ETT were developed; offering considerable benefits over the currently available material in terms of biomechanical and thermal properties. Clinical significance This study provided a new option for the development of a new intracanal post made up of functional and aesthetic composites.
The flow in a manifolds considered as an advanced problem in hydraulic engineering applications. The objectives of this study are to determine; the uniformity qn/q1 (ratio of the discharge at last outlet, qn to the discharge at first outlet, q1) and total head losses of the flow along straight and rectangular loop manifolds with different flow conditions. The straight pipes were with 18 m and 19 m long and with of 25.4 mm (1.0 in) in diameter each. While, the rectangular close loop configuration was with length of 19 m and with diameter of 25.4 mm (1.0 in) also. Constant head in the supply tank was used and the head is 2.10 m. It is found that outlets spacing and manifold configuration are the main factors aff
... Show MoreThe research aims to identify motivated to join the Evening Studies students to the College of Education at the University of Tikrit sections. In addition to knowledge of the differences in the degree of motivation of students according to gender, specialty, educational stage. To achieve the objectives of the research scholar us a measure consisting of (34) paragraph formulated positively, have been applied to a stratified random sample strength (500) students.
The results showed that the degree of motivation was very big on all areas of the college and class, reaching the percentage of response (84.3%), and professional motives came first prize as a percentage of (93.8%), in addition
... Show MoreThe right of the patient to know the medical risks surrounding the medical intervention is one of the most prominent rights based on the principle of "physical safety", which has undergone several stages of development until it reached the development of the patient's independence in making medical decision without relying on the doctor, The patient's prior informed consent is informed of his / her medical condition. We will study this development in accordance with the French March 4, 2002 legislation on the rights of patients in the health system, whether it was earlier and later. We will highlight the development of the patient's right to "know the medical risks surrounding medical intervention" The legislation and its comparison with th
... Show MoreGreen areas are an essential component of city planning, as they serve as an outlet for them to spend their free time, in addition to the environmental role that these green areas play in improving the city’s climate by purifying the air and beautifying the city. The study’s problem is summarized in identifying the appropriateness of the current spatial distribution of green areas in the city of Najaf with the current population densities and the pattern in which green areas are distributed using GIS and knowing the per capita share of those green areas in the city, the research assumes that the inconsistency of spaces between regions Green and residential neighbourhoods need to c
Abstract The wavelet shrink estimator is an attractive technique when estimating the nonparametric regression functions, but it is very sensitive in the case of a correlation in errors. In this research, a polynomial model of low degree was used for the purpose of addressing the boundary problem in the wavelet reduction in addition to using flexible threshold values in the case of Correlation in errors as it deals with those transactions at each level separately, unlike the comprehensive threshold values that deal with all levels simultaneously, as (Visushrink) methods, (False Discovery Rate) method, (Improvement Thresholding) and (Sureshrink method), as the study was conducted on real monthly data represented in the rates of theft crimes f
... Show MoreThe diversity of ideas and freedom of expression among the authors, who are looking for what's new serve the goals of musical expression and aesthetic, which calls for the use of traditional instruments with the formation of the great instrumental music and well-known orchestra, is a major challenge from several quarters, the failure of some of those musical instruments or limited potential or method performed by costly sometimes prevents the use of a permanent in this great configuration, had to be the emergence of some of the problems faced by the author and musician on the one hand and the receiver on the other hand, which must be looking for the perfect, some of these musical instrument are used systematically follows the work of the
... Show Moreهدف 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 MoreTheater is a renewed art until this moment, and it does not stray from its components from life and its spaces in general, but rather is derived from them according to characteristics and directions intended to differ based on finding other, more effective solutions, Therefore, the research entitled (Extractive treatments of the space between tradition and contrast in contemporary theater) consists of four chapters. The first chapter came under the title (the methodological framework). Where he dealt with the research problem and then the importance of the research and the goal of the research as well as the objective, temporal and spatial limits of the research, In addition to defining the terminology and then finding the procedural ter
... Show MoreThe present study aimed at identifying the level of psychological alienation and motivation of achievement among the incoming teachers in the schools of Dhofar Governorate in the Sultanate of Oman a well as to explore the correlation relationship between psychological alienation and motivation of achievement. The sample of the study consisted of (238) expatriated teachers from Al- Dhofar Governorate in Oman who were selected randomly. The psychological alienation scale and the motivation of achievement scale for teachers were used by researchers and were conducted electronically by google forms. The data were processed statistically using the Statistical Package for Social Sciences (SPSS). The results showed that the level of psy
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