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.
Societal security is regarded as a basic need for human society through which the stability, progress and prosperity of the nation is measured. It is the guarantor of the safety of individuals and groups from various internal and external dangers, based on the protection of the three pillars: the individual, the family, and society. For decades, Iraq has witnessed the phenomenon of political instability, represented by its entry into several wars, starting with the 1948 war, leading up to the American war on Iraq in 2003. Then, those wars were followed by an era in which corruption and terrorism spread, and this, in turn, led to the fragmentation of the national will and the division of Iraqi public opinion regarding many regional and inte
... Show MoreThe aim of this study was to making an analytical study in some kinematics variables in (200) meter breaststroke swimming to first ranking in championship 2003 – Spanish. The swimming in our country still suffering from several obstruction with retarded it’s development for the better since the investigators observe the insufficiency of swimming in our country to any analytical study for the international champions, this led to no specific and scientific discovering to these advanced levels as the estimation of the value of performance from the Iraqi coaches dependent on personality observation dependent on their opinion without referring to the specific and scientific diction. The investigators dependent on several kinematics variables
... Show MoreThe study was conducted to show the effect of using dried rumen powder as a source of animal protein in the diets of common carp (Cyprinus carpio L.) on its performance, in the fish laboratory/College of Agricultural Engineering Sciences/University of Baghdad/ for a period of 70 d, 70 fingerlings were used with an average starting weight of 30±3 g, with a live mass rate of 202±2 g, randomly distributed among five treatments, two replicates for each treatment and seven fish for each replicate. Five diets of almost identical protein content and different percentages of addition of dried rumen powder were added. 25% was added to treatment T2 and 50% to treatment T3 and 75% of the treatment T4 and 100% of the treatment T5
... Show MoreElectrical Discharge Machining (EDM) is a non-traditional cutting technique for metals removing which is relied upon the basic fact that negligible tool force is produced during the machining process. Also, electrical discharge machining is used in manufacturing very hard materials that are electrically conductive. Regarding the electrical discharge machining procedure, the most significant factor of the cutting parameter is the surface roughness (Ra). Conventional try and error method is time consuming as well as high cost. The purpose of the present research is to develop a mathematical model using response graph modeling (RGM). The impact of various parameters such as (current, pulsation on time and pulsation off time) are studied on
... Show MoreBackground: Blood group system and the ability to taste phenylthiocarbamide (PTC) are the most studied traits in human genetics which have been extensively used in describing genetic variations among human populations around the world that may had an effect on dental caries. The aims of present study were to investigate the caries experience among students with different bitter taste threshold in relation to blood type. Materials and Methods: The sample of present study includes dental students female aged19-21 years. The diagnosis of dental caries was done according to the criteria of Manjia et al, 1989 recording decayed lesion by severity (D1-4) MFS. Furthermore, bitter taste sensitivity was measured according to PTC (phenylthiocarbamid
... Show MoreThis study has been accomplished by testing three different models to determine rocks type, pore throat radius, and flow units for Mishrif Formation in West Qurna oilfield in Southern Iraq based on Mishrif full diameter cores from 20 wells. The three models that were used in this study were Lucia rocks type classification, Winland plot was utilized to determine the pore throat radius depending on the mercury injection test (r35), and (FZI) concepts to identify flow units which enabled us to recognize the differences between Mishrif units in these three categories. The study of pore characteristics is very significant in reservoir evaluation. It controls the storage mechanism and reservoir fluid prope
The experiment was conducted at the plant tissue culture laboratory of the Department of Horticulture and Garden Engineering College of Agricultural Engineering Sciences, University of Baghdad, in order to study the effect of some growth regulators on propagation an stimulation production of volatile oil compounds of rosemary plant Rosmarinus officinlis using two vegetative parts (apical and lateral buds). Factorial experiment was implemented in completely randomized design with twenty replications. The results indicated that culturing the apical meristem on the medium Murashige and Skoog (MS) media with 0.5 mg.l-1 (BA) with 0.1 mg.l-1 of NAA gave the highest response rate of 100%. As for the doubling stage, the levels of BAA and IAA (Indol
... Show MoreThis study aimed at identifying the trend to applying the Joint Audit as an approach to improve the financial reports quality with all their characteristics (Relevance, Reliability, Comparability, Consistency), as well as enclose the difficulties that faced the auditors in the Gaza Strip in implementing the Joint Audit. In order to achieve the study aims, a measure was used to identify the trend to apply the Joint Audit and it was distributed to the study sample which is consisting of (119) individuals and retrieved thereof (99) valid for analysis, approximately (83.2%), (69) of them are Auditors, (30) financial managers and accountants. The researcher used the analytical descriptive method, and after analyzing the results, the s
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