Background: Debonding orthodontic brackets and removal of residual bonding material from the enamel surface include critical steps that may cause enamel damage. The aim of the present study was to evaluate and compare the site of bond failure and enamel surface damage after debonding of three types of esthetic brackets (composite, ceramic, sapphire) bonded with light cure composite and resin-modified glass ionomer adhesive. Materials and methods: Seventy two maxillary premolars teeth were divided into three groups each group consisted of 24 teeth according to the type of brackets. Each group was subdivided into two subgroups (12 teeth for each) according to the bonding material that was used. After 7 days of bonding procedure, the brackets were debonded using specifically designed debonding device in which the brackets were debonded by a debonding pliers to simulate the actual clinical debonding procedure. Instron Universal testing was used to apply the debonding force on the debonding pliers which transferred to the bracket. The teeth and the brackets were examined with a 10X magnifying lens to evaluate the site of failure. After the removal of residual adhesive, stereomicroscope was used to evaluate enamel surface damage. Results: The most common type of bond failure was cohesive failure (Score II) in all esthetic brackets. While enamel cracks (scale I) were found to be the most type of enamel damage. Chi- square showed non-significant differences among different types of esthetic bracket bonded with same type of adhesive and between the same types of brackets (ceramic, sapphire) bonded with the two types of adhesive. On the other hand, there was significant difference between composite brackets subgroups bonded with the two adhesives. Conclusion: The bond failure mostly within the adhesive itself and higher enamel damage was resulted from mechanical debonding of these esthetic brackets.
Magnesium hydroxide was used as flame inhibitor to increased flame resistance for tires .Magnesium hydroxide was adding with (5%,10%) weight percents to rubber master batch of tire and then exposed the resulting material to a flame generated from gas torch with (10 mm) exposure distance . Method of measuring the surface temperature opposite to the flame was used to determine the heat transferred through tire material. The results were obtained shows enhanced flame resistance for tire by added magnesium hydroxide and this resistance increased by increasing hydroxide Percentage .
Background: Although the issue of anemia after renal transplantation (RT) has received increasing attention lately, the data on the exact prevalence of post-transplantation anemia (PTA) in the Iraqi patients are limited. Objective: In this study we sought to determine the prevalence of PTA among Iraqi patients and to correlate the renal allograft function measurements and the use of immunosuppressant with the prevalence of anemia. Patients and Methods: One hundred and twelve (74 male, 38 female) kidney transplant recipients (KTR) attending the kidney transplant center at surgical specialties hospital were studied. All patients were on maintenance, combined immunosuppressive therapy. The renal function tests [blood urea, serum cre
... Show MoreBackground: This in vitro study compares a novel calcium-phosphate etchant paste to conventional 37% phosphoric acid gel for bonding metal and ceramic brackets by evaluating the shear bond strength, remnant adhesive and enamel damage following water storage, acid challenge and fatigue loading. Material and Methods: Metal and ceramic brackets were bonded to 240 extracted human premolars using two enamel conditioning protocols: conventional 37% phosphoric acid (PA) gel (control), and an acidic calcium-phosphate (CaP) paste. The CaP paste was prepared from β-tricalcium phosphate and monocalcium phosphate monohydrate powders mixed with 37% phosphoric acid solution, and the resulting phase was confirmed using FTIR. The bonded premolars were exp
... Show MoreAbstract :
The research aims to study the basic concepts of banking productivity and discuss different approaches to study what ends to identify the most important possible standards applied to measured within the Iraqi banking environment as well as research into the causes of low and high Iraqi banking productivity and identify possible treatments to curb those reasons as to ensure the rise. And in line with the research problem, which states what is the level of productivity and what are the causes of decline and the rise in private banking research sample individually. And what the Iraqi private banks and what is the relationship between performance and the impact of productivity change in the perform
... Show MoreThe tagged research problem (the outputs of the written text in conceptual art) dealt with a comparative analytical study in the concept of conceptual art trends (land art - body art - art - language).
The study consisted of four chapters. The first chapter dealt with the theoretical framework, which was represented in presenting (the research problem), which raised the following question: What is the role of the written text in the transformations of the conceptual arts?
The first chapter included (the importance of research) and (research objectives) seeking to conduct comparative research in the written text within the trends of conceptual art as a moving phenomenon in art, and to reveal the variable written text in the
... Show MoreEcolinguistics is a twofold field in which ecology and language are its two major concerns. That is, this field is concerned with the way through which our thoughts, ideologies and the like influence the environment. The present study aims at analyzing (6) constructive and destructive environmental advertisements to find out how the techniques of erasure and salience operate in these types of advertisements. It studies the linguistic expressions that achieve these techniques in the constructive and destructive advertisements. The qualitative and quantitative methods are exploited in the current study. Analyzing (6) constructive and destructive environmental advertisements in accordance with Stibbe’s (2015) model of salience and erasure
... Show MoreIn this work an approach has been developed to investigate the influence of surface roughness on thermohydrodynamic performance in aligned and misaligned journal bearings by considering an average flow model and deriving the shear flow factor for various roughness configurations, similar to the pressure flow factor. An average Reynolds equation for rough surfaces is defined in term of pressure and shear flow factors, which can be obtained by numerical flow simulation, though the use of measured or numerically generated rough surfaces. Reynolds, heat conduction and energy equations are solved simultaneously by using a suitable numerical technique (Finite Difference Method) to obtain the pressure and temperature di
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