Background: Relapse of previously moved teeth, is major clinical problem in orthodontics with respect to the goals of successful treatment. This study investigated the effect of orthodontic relapse on the proliferation of fibroblast and epithelial rests of Malassez cells in periodontal ligament of rat molars. Materials and Methods: Sixteen ten-week- old male Wister rats were randomly divided into four groups composed of four animals each: Group I received no orthodontic force (control). In both Group II and Group III, uniform standardized expansive springs were used for moving the maxillary first molars buccally for periods of one and three weeks respectively. The spring initially generated an average expansive force of 20 g on each side. In Group IV the springs were left for three weeks, until the maxillary first molars moved buccally, after that the springs were removed and the animals were scarified after three weeks of relapse tooth movement. After the humanly scarification of animals, each maxilla in all groups was dissected into two halves each half including the three maxillary molars and processed for histological examination. The number of both fibroblast and ERM cells in each cluster was counted in the PDL of the pressure side of the mesio-buccal roots of the maxillary right and left first molars in all groups and the surface areas of the ERM clusters were also measured in all groups. Results: The number of fibroblast was significantly increased at the end of active movement (Group III) and significantly very highly increased during the relapse period (Group IV). Regarding the ERM cells there were statistically significant increase in both the number of cells in each ERM cluster and the surface areas of the ERM clusters in Group III and highly significant increase in Group IV, while Group II showed no significant differences regarding all measurements. Conclusions: It was concluded that fibroblast and ERM cells may play an important role during orthodontic relapse
The current research focuses on the extent to which the strategic orientation(entrepreneurial orientation, customer orientation, technology orientation, learning orientation, and investment orientation) affects the learning organization (building common vision, systemic thinking, personal dominance, mental models, team learning)The first hypothesis to test the connection relation between research variables and The second hypothesis was to test the relationship between these variables. In order to ascertain the validity of the hypotheses, the research was based on a questionnaire questionnaire prepared according to a number of In addition to building a fifth sub-variable for the strategic orientation (investment orientation) based
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The present study addressed "Performance Appraisal of Human Resource Management and Its Effect on Achieving the Organizational Success", for the topics of performance appraisal of human resource management and the organizational success gained an increasing interest being relatively important and modern topics which had a great effect on the future of organizations.
The study aimed at revealing the pattern of appraising the performance of human resource management for the study sample, and whether it was qualified to lead the ministry towards the organizational success, for this purpose two main hypotheses were formulated: 1) there is a positive significant correlation between both variables: performanc
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Soft clays are generally characterized by low shear strength, low permeability and high compressibility. An effective method to accelerate consolidation of such soils is to use vertical drains along with vacuum preloading to encourage radial flow of water. In this research numerical modeling of prefabricated vertical drains with vacuum pressure was done to investigate the effect of using vertical drains together with vacuum pressure on the degree of saturation of fully and saturated-unsaturated soft soils. Laboratory experiments were conducted by using a specially-designed large consolidometer cell where a central drain was installed and vacuum pressure was applied. All tests were conducted
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The current research aims to examine the effect of the Adi and Shayer model on the achievement of fifth-grade students and their attitudes toward history. To achieve the research objective, the researcher has adopted two null hypotheses. 1) there is no statistically significant difference at the level of (0.05) between the average score of students of the experimental group who study the history of Europe and modern American history according to the model of Addie and Shayer, and the average scores of the students of the control group who study the same subjects according to the traditional method in the test of post-achievement. 2) There was no statistically significant difference at the level (
... Show MoreMarriage is a holly secret in Christian religion .So it id natural that its ceremonies acquired religious form .In general the marriage is contracted by minister of religion in presence of the two parties or by a proxy or presence of parents if it is necessary . And to make the condition of publicity for the marriage ,its procedures must be made before witnesses .Also the minister of religionhave to confirm the agreement of the two parties before beginning the procedures.The marriage ceremonies are made.These procedures are religious traditions that includes praying and make blessings and putting the rings in fingers by thepriest . The marriage is a holly secret performed by the crown pray according to the church religious traditions
The present study aims at analyzing the polysemy of the English preposition in from the cognitive linguistic (CL) point of view using Evans' and Tyler's approach (2003). The perplexity faced by Iraqi second language learners (L2) due to the multi-usages of this preposition has motivated the researcher to conduct this study. Seventy-six second year university students participated in this experimental study. The data of the pre-test and post-test were analyzed by SPSS statistical editor. The results have shown the following: First, a progress of more than (0.05≤) has been detected as far as students' understanding of the multiple usages of the preposition in is concerned. Second, the results of the questionnaire have s
... Show MoreIn this paper, there are two main objectives. The first objective is to study the relationship between the density property and some modules in detail, for instance; semisimple and divisible modules. The Addition complement has a good relationship with the density property of the modules as this importance is highlighted by any submodule N of M has an addition complement with Rad(M)=0. The second objective is to clarify the relationship between the density property and the essential submodules with some examples. As an example of this relationship, we studied the torsion-free module and its relationship with the essential submodules in module M.
This study aimed to identify the effect of resistance training on the biomechanics and accuracy of serve receiving skills in volleyball. The research community was composed of 26 young volleyball players of Baghdad volleyball clubs. A total of 4 players were selected for the preliminary experiment, while 14 participants were recruited as the main sample for the study. In the present study, a set of resistance exercises were designed by the researchers for the volleyball players of the sample. Exercises were performed by the sample participants during the course of study. The biomechanical variables considered in the present study were: Preparation moment (shoulder joint angle, hip angle, knee joint angle), moment of pr
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The aim of our current study was to identify the effect of particulate matter of both types (PM2.5 and PM10) resulting from hookah smoking on the hemopoietic system of workers (smokers) in closed cafes. This study included six stations (cafes) on the Rusafa side of Baghdad city and conducted a blood test that included a complete blood count (CBC). A multifunctional air quality detector measured both types of particulate matter in the morning and evening. The study included 30 men (workers and smokers) and 30 men (non-smokers), whose ages ranged from 20 to 40 years. The study found that smokers had an increase in white blood cells and red blood cells, as well as an increase in the percentage of hemoglobin (HGB), hematocrit (HCT), the mean co
... Show MoreBackground: The success and maintenance of indirect dental restorations is closely related to the marginal accuracy, which is affected by many factors like preparation design, using of different fabrication techniques, and the time of taking final impression and pouring it. The purpose of this in vitro study was to evaluate the effect of different pouring time of conventional impression on the vertical marginal gap of full contour zirconia crowns in comparison with digital impression technique. Materials and Methods: Forty sound recently extracted human permanent maxillary first premolar teeth of comparable size and shape were collected. Standardized preparation of all teeth samples were carried out to receive full contour zirconia crown re
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