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
Seeds of the two rice genotypes namely Amber 33 (A33) and Amber Baghdad (AB) were divided into two groups; the first was presoaked in different concentrations of ethyl methane sulphonate (EMS) as chemical mutagen for different duration times (3, 6 and 12) hrs, and the other was exposed to different exposure times of ultra violate (UV-B) radiation (280-320 nm) as physical mutagen for different times (20, 40 and 60) min at room temperature. Treated and non-treated seeds were transferred into the callus induction medium containing 2.5 mg/L 2,4- dichlorophenoxy acetic acid (2,4-D) and 0.5 mg/L benzyl adenine (BA) under aseptic conditions. Calli were divided into two groups the first was treated with several EMS concentrations (0.0, 0.50. 1.0, 1
... Show MoreThe purpose of this study was to investigate the effect of a Cognitive- Behavioral Training Program in reducing Problems Solving among a sample of education university College Students, the study sample consisted of (50) students were randomly assigned to two groups: experimental, and control; (25) students per group, the results of (ANOVA) revealed that there were significant differences at (p < 0.05) between experimental and control group in Problems Solving level, while there were significant differences between both groups in achievement. The researchers recommended further studies on the other variables which after training students on the method of solving problems and techniques to reduce stress.<
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This research was interested in studying the phrase “I don’t know” in the Lisan al-Arab dictionary, and Lisan al-Arab was based on collecting its material from five dictionaries, including: Tahdhib al-Lugha, al-Muqamah, al-Sahih, and the footnotes of Ibn Berri, al-Nihaya and Gharib al-Hadith. The objection to this phrase, and the discussion of its various implications among linguists and the clarification of the closest and most famous content to it according to the data presented to the researcher in his research journey, and to reach this goal, the research division into a preface, five demands and a conclusion and followed the list of sources and references. To define the lexicon of Lisan al-Ar
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This research aims to clarify the conceptual framework of social entrepreneurship shows the importance of the development of social entrepreneurship according to the contextual aspects and the social value achieved from these works. It also identifies the degree of level of a sample of women entrepreneurs in Iraq for the extent of the relationship between social entrepreneurship and women's empowerment. It also explains the impact of entrepreneurial work in empowering women and the extent to which there are individual differences between the average scores of the sample members’ estimation of the level of social entrepreneurship according to social status, age group, educational qualification, and specialization according to the s
... Show MoreClimate change is a global environmental issue and a common concern for humanity, and it is an inevitable result of civilization development, especially after the industrial revolution All areas of life At the level of the Iraqi situation , Iraq faces several challenges posed by Climate change , Such as high temperature, lack of rain, water scarcity , land salinity , and the increase in the proportion of sand and dust storms and the resulting disasters, which impedes development and hinders efforts to reduce poverty , enhance livelihoods , and reduce conflict to obtain natural resources.
... Show MoreBackground: Decalcification of surface enamel adjacent to fixed orthodontic appliances, in the form of white spot lesions, is a wide spread and familiar well-known side effect of orthodontic treatment. The present study was carried out to evaluate the effect of enamel protective agent (Clinpro white varnish) on shear and tensile bond strength of Dentaurum orthodontic stainless steel brackets by using 3M Unitek and Ormco as orthodontic adhesive agents. Materials and methods: Sixty-four extracted human upper first premolar teeth were selected and randomly divided into two groups with 32 teeth each, representing the shear and tensile bond strength testing groups. Then according to the type of bonding adhesive and the addition of Clinpro before
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The research aims at identifying The Effect of Woods model in the Acquisition of Grammatical Concepts on students at the Sixth Primary. The total number of students is (49) male and female. students are distributed in two groups . The First group is the experimental group which is taught the( Woods Model) and it is (25) students . The second group is the control group which is taught according to the traditional method of teaching and it is (24) students . The researcher has matched between the two groups by the following variables : the age (in months), their intelligence, their parents, academic level of education . The research has constructed multiple choice test of (20) items . The reliability of The test has been calculated and it
... Show MoreThe current study examined the effect of different sample sizes to detect the Item differential functioning (DIF). The study has used three different sizes of the samples (300, 500, 1000), as well as to test a component of twenty polytomous items, where each item has five categories. They were used Graded Response Model as a single polytomous item response theory model to estimate items and individuals’ parameters. The study has used the Mantel-Haenszel (MH) way to detect (DIF) through each case for the different samples. The results of the study showed the inverse relationship between the sample size and the number of items, which showed a differential performer.