Background: The bonded orthodontic retainer constructed from multistrand wire and composite is an efficient esthetic retainer, which can be maintained long-term. Clinical failures of bonded orthodontic retainers, most commonly at the wire/composite interface, have been reported. This in vitro investigation aimed to evaluate the tensile forces of selected multistrand wires and composite materials that are available for use in the construction of bonded fixed retainers. Materials and Methods: The study sample includes 120 wires with three types of retainer wires (3 braided strands\ Orthotechnology, 8 braided strands\ G&H Orthodontics, 6 coaxial strands\ Orthoclassic wires), two types of adhesive (flowable\ Orthotechnology, non flowable\ G&H Orthodontics composites) and two thickness of the adhesive (1mm, 2mm). The samples were prepared for each composite in which a wire was embedded; then the composite was light cured for 40 seconds and the specimens were stored in artificial saliva at 37°C in the incubator for 24 hours. The ends of the wire were drawn up and tensile force was applied through Tinius-Olsen universal testing machine until the resin failed and the results were recorded in Newton (N). Results: Statistical analysis showed that there was a highly significant difference (P ≤ 0.01) among the mean values of tensile forces of the three types of retainer wires in each thickness of composite with exception of a non significant difference (P > 0.05) between (3 braided) and (8 braided) and a non significant difference (P > 0.05) between (3 braided) and (6 coaxial) in both thickness of composite, a highly significant difference (P ≤ 0.01) between the two thickness of both composite types in each wire type and a highly significant difference (P ≤ 0.01) between the two types of composite in each wire type of both thickness of composite. Conclusion: The result of this study revealed that the 8 braided strands retainer wire shows the highest values of tensile force among the tested retainer wires, the non flowable composite demonstrates a higher tensile force than the flowable composite and increasing the thickness of composite overlying the wire increased the force required to detach the wire from the composite.
The problem of the study and its significance:
Due to the increasing pressures of life continually, and constant quest behind materialism necessary and frustrations that confront us daily in general, the greater the emergence of a number of cases of disease organic roots psychological causing them because of severity of a lack of response to conventional treatments (drugs), and this is creating in patients a number of emotional disorders resulting from concern the risk of disease
That is interested psychologists and doctors searchin
... Show MoreIntroduction: Diabetic foot infections are one of the most severe complications of diabetes. This study was aimed to determine the common bacterial isolates of diabetic foot infections and the in vitro antibiotic susceptibility then treatment.
Methods: A swab was taken from the foot ulcer, and the aerobic bacteria were isolated and identified by cultural, microscopic and biochemical test, then by api-20E system. After that their antibiotic susceptibility pattern was determined. Then local and systemic treatment was used to treat the diabetic foot patients.
Results: Bacterial isolates belonging to twelve species were obtained from diabetic foot patients. Gram (-) bacteria were the predominant pathogens in the diabetic foot infection
The study aimed to monitor the concept of reputation in the previous literature, its relationship to mental image and identity, and to reveal recent trends in its measurement Techniques.
The study relied on a descriptive approach using library survey and comparative analysis, and the study reached following conclusions:
Despite the beginning of the first signs of reputation In the fifties of the last century, however, Defining and standardizing the concept with clear and specific dimensions began in the 1990s and the beginning of the third millennium. The concept of reputation refers to the stakeholders’ overall evaluation of organizations, which reflects their perceptions of
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Interface bonding between asphalt layers has been a topic of international investigation over the last thirty years. In this condition, a number of researchers have made their own techniques and used them to examine the characteristics of pavement interfaces. It is obvious that test findings won't always be comparable to the lack of a globally standard methodology for interface bonding. Also, several kinds of research have shown that factors like temperature, loading conditions, materials, and others have an impact on surface qualities. This study aims to solve this problem by thoroughly investigating interface bond testing that might serve as a basis for a uniform strategy. First, a general explanation of how
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Interface bonding between asphalt layers has been a topic of international investigation over the last thirty years. In this condition, a number of researchers have made their own techniques and used them to examine the characteristics of pavement interfaces. It is obvious that test findings won't always be comparable to the lack of a globally standard methodology for interface bonding. Also, several kinds of research have shown that factors like temperature, loading conditions, materials, and others have an impact on surface qualities. This study aims to solve this problem by thoroughly investigating interface bond testing that might serve as a basis for a uniform strategy. First, a general explanation of how the bonding strength
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ABSTRACT Background: Improving the properties of heat- cured and self-cured acrylic resin have been studied by many researchers. However, little studies concerned with visible light cured resin (VLCR) improved through addition of nanofiller are available. The purpose of this study was to evaluate some properties of (VLCR) after addition of SiO2 nanofiller. Materials and Methods: SiO2 nanofiller were added to (VLCR) tray material after being dissolved in tetrahydrofuran (THF) solvent. According to the pilot study 2% SiO2 nanofiller addition exhibited better properties than the other percentages (1%, 3%). The main study conducted involved (100) specimens divided into 5 groups according to the test included. (20) Specimens were selecte
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Most reinforced concrete (RC) structures are constructed with square/rectangular columns. The cross-section size of these types of columns is much larger than the thickness of their partitions. Therefore, parts of these columns are protruded out of the partitions. The emergence of columns edges out of the walls has some disadvantages. This limitation is difficult to be overcome with square or rectangular columns. To solve this problem, new types of RC columns called specially shaped reinforced concrete (SSRC) columns have been used as hidden columns. Besides, the use of SSRC columns provides many structural and architectural advantages as compared with rectangular columns. Therefore, this study was conducted to explain the structura
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Objective: To evaluate and compare the effect of mechanical surface treatment (groove, aluminum oxide particles)
with 45 degree bevel type of joint on tensile bond strength of acrylic specimens repaired by two curing methods
(microwave and water both).
Methodology: Eighty specimens (80) were prepared from pink heat cure acrylic resin. They were divided into two
main groups (40 specimen repaired by microwave energy and 40 specimens repaired by water bath method).Each
group can be divided into four subgroups of ten according to the surface treatment. The control group A was left
intact, group B received no surface treatment, group C and D received surface treatment by (groove, 50 m aluminum
oxide particles). Specimens
Metaphor is one of the most important linguistic phenomena of the artistic text, as it is the expression of the author’s emotions and evaluations, the result of a deep inner transformation of the semantic words and visual means of reflecting the national culture of each people. This paper examines the concept of linguistic metaphors and analyzes its types in the Russian and Arabic linguistics, provides a comparative analysis of metaphors in Russian and Arabic — all this allows to conclude that metaphorization is characteris- tic of different parts of speech. In the Russian language stylistic differentiation of the metaphors expressed more than in Arabic, so translation of many “sty- listic” metaphors from Russian into Arabic due to
... Show MoreBackground: Esthetic treatment is the options of patient seeking orthodontic treatment. Therefore this study was conducted to measure the concentration of Aluminum, Nickel, Chromium and Iron ions released from combination of monocrysralline brackets with different arch wires immersed in artificial saliva at different duration, to evaluate the corrosion point on different parts of the orthodontic appliances before and after immersion in artificial saliva, and to evaluate the corrosion potential of each group of the orthodontic appliances. Material and methods: Eighty orthodontic sets prepared. Each set represents half fixed orthodontic appliance, from the central incisor to the first molar, for the maxillary arch, each set consisted of molar
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