Background: With the increased in the demands of adult orthodontics, the challenge of direct bonding to non-enamel surface (zirconium) had been increased. The present study was carried out to compare the shear bond strength of three different brackets (stainless steel, sapphire and composite) bonded to zirconium surface and study the mode of bond failure. Materials and methods: The sample was comprised of 30 models (8mm *6mm*1.5mm) of full contour zirconium veneers. They were divided into three groups according to the brackets type; all samples were treated first by sandblast with aluminum oxide particle 50 µm then coated by z-prime plus primer. A central incisor bracket of each group was bonded to the prepared zirconium surface with light cure adhesive resin (Transbond TM XT, 3M Unitek, USA). Shear bond strength was measured by using Tinius Olsen universal testing machine at crosshead speed of 0.5\min. After debonding, each bracket and zirconium surface were examined using magnifying lens and adhesive remnant index was recorded. The difference in shear bond strength between main groups was analyzed by using ANOVA at p≤0.05. Results: The results revealed high significant difference among all tested groups and the highest value was for sapphire brackets (7.49±1.45 Mpa) of all groups followed by stainless steel brackets (6.46±1.43Mpa) and composite brackets had the least value (4.35±0.72). Non-significant difference in the site of bond failure among all groups of brackets and zirconium-adhesive interface failure (score III) was the predominant. Conclusion: the new zirconium prime plus primer can be successfully used in bonding stainless steel and sapphire brackets to zirconium surface.
The monogeneans Gyrodactylus dzhalilovi Ergens & Ashurova, 1984, G. magnus Konovalov, 1967 and G. matovi Ergens & Kakachava-Avramova, 1966 were recorded in this study for the first time in Iraq from gills of the common carp Cyprinus carpio Linnaeus, 1758 collected from Tigris River in Baghdad city. The description, measurements and illustrations of these parasites were given.
Importance of accounting standards belong to be the instructor and the advisor for accountant in performing his work . For each invironment a group of political, social, economical and cultural factors which distinguish it about other environments . In order to perform its aim in produsing accouting information helps in making decisions on different levels, accounting standards should established in a form that harmonized with the environment that apply in it . Establishing international accounting standards comes with the same direction and then it has put influential with standards some states that have influence on international accounting standards committee. So because of the big changes that happened in the inte
... Show MorePolycystic ovary syndrome (PCOS) is a complex endocrine–metabolic disorder characterized by hyperandrogenism, ovulatory dysfunction, insulin resistance, and chronic inflammation resulting in reproductive and metabolic complications. Traditional metformin therapy improves insulin sensitivity, while newer dual incretin agonists, such as tirzepatide, may offer broader metabolic and ovarian protection. The objective of this study is to investigate whether tirzepatide could alter hormonal parameters, metabolism, inflammation, and histopathology of a testosterone propionate–induced PCOS rat model compared with metformin. Thirty prepubertal female Wistar rats were divided into five groups (n = 6). PCOS was induced by testosterone propionate (1
... Show MoreThis paper presents experimentally a new configuration of shear connector for Steel-Concrete-Steel (SCS) sandwich beams that is derived from truss configuration. It consists of vertical and inclined shear connectors welded together and to cover steel plates infilled with concrete. Nine simply supported SCS beams were tested until the failure under a concentrated central load (three- point bending). The beams were similar in length (1100mm), width (100mm), and the top plate thickness (4mm). The test parameters were; beam thickness (150, 200, 250, and 300mm), the bottom plate thickness (4, and 6mm), the diameter of the shear connectors (10, 12, and 16mm), and the connector spacing (100, 200, and 250mm). The test results sh
... Show MoreBackground: Denture lining materials are widely used in prosthodontic treatment and management of traumatized oral mucosa. A contaminated prosthesis can provide a source of cross-contamination between patients and dental personnel as well as a cause for denture stomatitis. Therefore, denture disinfection has been recommended as an essential procedure for maintenance of a healthy oral mucosa. This study investigated the effect of SOLO disinfectant solution on some properties of different denture lining materials. Materials and methods: Three different solutions were used in this study; SOLO disinfectant solution, sodium hypochlorite solution, and water on three types of acrylic denture lining materials; hot cure, cold cure, and soft acrylic
... Show MoreThe performance of flexible pavements is significantly impacted by the permanent deformation (rutting) of asphalt pavements. Rutting shortens the pavement's useful service life and poses significant risks to those using the highway since it alters vehicle handling characteristics.. The aim of this research is to evaluate the permanent deformation of asphalt mixtures under different conditions,to achieve this aim 108 cylindrical specimens has been prepared and tested under repeated loading in uniaxial compression mode. Five factors were considered in this research, these factors represent the effect of environmental condition and traffic loading as well as mixture properties, they include testing temperature, loading condition (stress level
... Show MoreReverse shoulder arthroplasty is an increasingly common surgical intervention. However there are concerns and known limitations in relation to such joint replacement, while novel designs of reverse shoulder prostheses continue to appear on the market. Many claim to offer improvements over older designs but such assertions are difficult to validate when there is no consensus as to how such implants should be tested in vitro or even if such testing is necessary. In order to permit appropriate in vitro testing of reverse shoulder prostheses a unique, multi-station test rig was designed which was capable of applying motion in three axes to test prostheses. The shoulder simulator can apply up to 110° of motion in the flexion–extension and abd
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