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 subject of the act and its transformations in the presentation is of great importance at the level of study, analysis and interpretation, and through that the researcher adopted the following title (The Dramatic Act and Its Transformations in the Iraqi Theatrical Show). The play of Black Astronomy was chosen as a sample for analysis, and the aim of the research came in order to achieve a special knowledge of the extent of the transformation that occurred between the dramatic structure of the act and theatrical embodiment and its multiple elements of operation in the Iraqi theatrical shows. It was limited to the show of the Iraqi theater in the year (2020) and included the theoretical framework that accommodated three sections. As for
... Show MoreThis study aims to investigate the adequacy of composite cellular beams with lightweight reinforced concrete deck slab as a structural unit for harmonic loaded buildings. The experimental program involved three fixed-ends supported beams throughout 2140 mm. Three concrete types were included: Normal Weight Concrete (NWC), Lightweight Aggregate Concrete (LWAC), and Lightweight Fiber Reinforced Aggregate Concrete (LWACF). The considered frequencies were (5, 10, 15, 20, 25, and 30) Hz. It was indicated that the harmonic load caused a significant influence on LWAC response (64% greater than NWC) and lattice cracks were observed, especially at 30 Hz. As for LWACF slab, no cracks appeared,
In this research a theoretical study has been carried out on the behavior and strength of simply supported composite beams strengthened by steel cover plate taking into consideration partial interaction of shear connectors and nonlinear behavior of the materials and shear connectors. Following the procedure that already has been adopted by Johnson (1975), the basic differential equations of equilibrium and compatibility were reduced to single differential equation in terms of interface slip between concrete slab and steel beam. Furthermore, in order to consider the nonlinear behavior of steel, concrete and shear connectors, the basic equation was rearranged so that all terms related to materials are isol
... Show MoreIt is no secret to everyone that the Arab individual suffers from poor self-awareness and political awareness, which made the state and the importance of its existence and preserving its institutions not among his interests, which made researchers wonder about the possibility of strengthening it and the extent of its impact on the future of building the contemporary Arab state, so the study attempted Addressing the issue of community awareness and its impact on building the state through a clear intellectual vision that blended what is social and political to define the concept of community awareness and highlight its importance and role as a basic pillar in shaping and building modern Arab countries. In the Arab world and ways to enhanc
... Show MoreThe research seeks to find out the extent of the coverage of the Mosul press to the issues of psychological and social effects of the organization "IS" on the community of Mosul, by analyzing the content of the newspapers “Economic City” and “Mosul News”. As well as to stand at the types of psychological and social effects and their repercussions on the Mosul community including figures, statistics and evidence that were covered in the theoretical study of these topics.
This study is the first scientific diagnosis to reveal the size and types of psychological and social effects of the “ISIS” organization through what was monitored by the Mosul press. The study seeks to draw the attention of officials, decision-m
... Show MoreThis paper is dealing with an experimental study to show the influence of the geometric characteristics of the vortex generators VG son the thickness of the boundary layer (∂) and drag coefficients (CD) of the flat plate. Vortex generators work effectively on medium and high angles of attack, since they are "hidden" under the boundary layer and practically ineffective at low angles.
The height of VGs relative to the thickness of the boundary layer enables us to study the efficacy of VGs in delaying boundary layer separation. The distance between two VGs also has an effect on the boundary layer if we take into
... Show MoreThe present study aimed to determine the serum sex hormone levels among Benign Prostatic Hyperplasia (BPH) patients before and after 3 months of oral administration of 5-α reductase inhibitor(finasteride). Forty BPH patients and 40 healthy men from Amara city were involved in this study, their ages were between 40-59 year. They were all subjected to direct estimation of hormones by MinVidas method including Testosterone (T), Estradiol (E2), Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), Prolactin (PRL), and Dihydrotestosterone (DHT) before and after 3 months of treatment with 5α-reductase inhibitor (finasteride) (the healthy individuals didn’t take finasteride).The results showed that T level was significantly lo
... Show MoreIn diabetes, impaired wound healing and other tissue abnormalities are considered major concerns. Many factorsaffect the time and quality of wound healing. One of the purposes of medical sciences is wound healing in a short time withreduced side effects. The herbal products are more precious in both prophylaxis as well as curative in delayed diabetic woundhealing activity when compared to synthetic drugs.A wide range of evidence has shown that capers plant possesses differentbiological effects, including antioxidant, anticancer and antibacterial effects. Phytochemical analysis shows thatC. spinosahashigh quantities of bioactive constituents, including polyphenolic compounds, which are responsible for its health-promotingeffects. The healing
... Show MoreThe purpose of this study is to diagnose factors that effect Thi-Qar behavioral intention to use internet. A sample of (127) internet users of university staff was taken in the study and were analyzed by using path analyze . The study concluded that there is a set of affecting correlation. It was founded that exogenous variables (gender, income, perceived fun, perceived usefulness, Image, and ease of use) has significant effect on endogenous (behavioral intention) . The result of analysis indicated that image hopeful gained users comes first, ease of use secondly, perceived fan and perceived usefulness on (dependent variables (daily internet usage and diversity of internet usage. Implication of these result are discussed . the st
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