ABSTRACT Background: Bracket rebonding is a common problem in orthodontics which may result in many drawbacks. The aims of this study were to evaluate the effects of application of two enamel protective agents “Icon†and “ProSeal†on shear bond strength before and after rebonding of stainless steel orthodontic brackets using conventional orthodontic adhesive and to assess the site of bond failure. Materials and methods: Fifty sound extracted human upper first premolar teeth were selected and randomly divided into two equal groups; the first time bonding and the rebonding groups (n=30). Each group was subdivided into control, Icon and ProSeal subgroups. The enamel protective agents were applied after etching (preconditioners). Shear bond strength before and after rebonding of stainless steel brackets were assessed using the Universal testing machine and the adhesive remnant index was used to find out the bond failure site using a stereomicroscope. Then the results were statistically analyzed using one-way ANOVA analysis test and T-test. Results: There were no significant differences in the shear bond strength mean values in either group or their corresponding subgroups. Forty percentage of the bond failure in ProSeal groups occurred away from the enamel where 75% of those were at the enamel protective agents/adhesive interface. Conclusions: The application of Icon and ProSeal did not compromise the shear bond strength and the application of the ProSeal may protect the enamel surface from trauma (cracks, chipping or detachment).
A comprehensive practical study of typical mechanical properties of welded Aluminum alloy AA7020-T6 (Al-Mg-Zn), adopting friction stir welding (FSW) technique and conventional metal inert gas (MIG) technique, is well achieved in this work for real comparison purposes. The essences of present output findings were concentrated upon the FSW samples in respect to that MIG ones which can be summarized in the increase of the ultimate tensile strength for FSW was 340 MPa while it was 232 MPa for MIG welding, where it was for base metal 400 MPa. The minimum microhardness value for FSW was recorded at HAZ and it was 133 HV0.05 while it was 70 HV0.05 for MIG weld at the welding metal. The FSW produce 2470 N higher than MIG welding in the bending t
... Show MoreThe research aims to presenting a number of scenarios for the investment of the marshes. The problem of research problem was that there is no in-depth analysis of the marshes environment. The traditional methods of the environmental analysis are insufficient. The research community is represented by the decision makers in Maysan Governorate. The research led to proposing of three scenarios with statement the requirements for the success of each one. The most important conclusions are that the three proposed scenarios for marshes investment depend on the availability of the required volunteers for each scenario. The higher the availability of the requirements, the more optimistic the scenario becomes. If t
... Show MoreThe book The Laws of Duwan of Mamati's Son (T, 606 E) His approach to his narratives is a topic of historical and civilized importance. The Fatimid Age of the People of Jehovah has expanded its influence and authority, including ministers, writers, doughnuts and foreshores. One of the Christian families that shined in the late Fatmi era was "Mamati", who lived in "Assiut" from Upper Egypt, then moved to Cairo, and enrolled in the service of the Fatimids, where their sons held important positions in State offices.Ibn Mamati became in charge of the Army Office and then added to it the Finance Office, which became the most important downs in Egypt. Through his work in the Duwan Law Books, this book was a living record of the Dawawans in the Ay
... Show MoreIntroduction: An aneurysmal bone cyst are enigmatic lesionof unknown cause and presentation and are difficult todistinguish from other lesions, it is a benign, but expansibletumor like lesion that generally occurs in the long bones. Ananeurysmal bone cyst arising from the flat bone like clavicleis rare .Case presentation: We report a 12-year-old girl child with ananeurysmal bone cyst of the lateral third of left clavicletreated with enblock resection. The pathologic findingsconfirmed the diagnosis of aneurysmal bone cyst. Thepatient has been followed up for one year with no evidenceof recurrence .Conclusion: En bloc resection can be curative and provide good results for this rare type of clavicle tumour.
Background: Several risk managem-ent standards had been developed including the Project Management Institute, the National Institute of Standards and Technology, actuarial societies, and ISO standards.
Objective: The study aimed at evaluating risk management among managers of model and ordinary primary health care centers in Baghdad City and comparing the risk management among these centers.
Methods: A descriptive comparative des
... Show MoreThe study aims to display the scientific benefit offered by modern electronic programs for various scientific research methods, while determining the positive scientific role played by these programs in modernizing the methodologies and logic of scientific thinking, especially with the rapid development of the sciences and their curricula.
These programs link accurately with scientific results. The importance of the study is to provide practical mechanisms to highlight the scientific projection of the electronic programs in various steps of scientific research.
A case study was used for Tropes version 8.4, which analyzes written, audio and visual semantic texts and presents a set of statistical results that facilitate the difficult
A study conducted a laboratory experiment to measure the release of potassium and the dissolution of feldspar minerals in soils from different locations in Karbala Province (Ain Al-tamur, Qasr Al-Akhyar, Fadak Farm). The study involved the addition of organic acids (fulvic and humic) and mineral acids (sulfuric and phosphoric) at concentrations of 5% and 10% to sand-separated soil samples obtained through wet sieving. Feldspar minerals were identified using a polarized light microscope, and the percentage of each type of feldspar mineral was calculated. The results demonstrated that organic acids outperformed mineral acids in releasing potassium at both concentrations. Among the organ
In this research, A thin film of Rhodamine B dye and TiO2 Nanoparticles doped in PMMA Polymer has been prepared by a casting method. The sample was spectrum absorption by UV-Vis. The nonlinear optical properties were measured by Z- scan technique using Nd:YAG laser with (1064 nm) wavelength. The nonlinear refractive index (n2) and nonlinear absorption coefficient (β) were estimated for the thin film for different energies of the laser, n2 and β were decreased with increasing intensity of incident laser beam. Also, the type of β was two-photon absorption and n2 negative nonlinear reflective.