Aim: This study aimed to compare different types of ligation methods to obtain maximum tooth movement with the least undesirable rotation. Methods: Titanium brackets bonded to acrylic canine teeth were ligated to straight stainless steel (SS) archwires using four ligation methods (figure-O and figure-8 elastics, SS ligatures, and Leone Slide ligatures). The teeth with the ligatures in place were stored in a water bath at 37ºC for 1 day, 1 week, 2, 4 or 6 weeks before testing. The teeth were retracted through softened wax along the archwire and the amount of tooth movement and degree of rotation were measured. Results: Slide ligatures showed the highest distance of tooth movement and degree of canine rotation followed by figure-O elastics, while figure-8 elastics showed the least amount of retraction and degree of rotation. SS ligatures showed moderate tooth movement with a minimal degree of rotation. Conclusions: The study recommends the use of loose SS ligatures for canine retraction in sliding mechanics, while Slide elastic ligatures are best used in leveling and aligning stage of crowded teeth since they showed reduced friction with the archwire.
Preparation of epoxy/ TiO2 and epoxy/ Al2O3 nanocomposites is studed and investigated in this paper. The nano composites are processed by different nano fillers concentrations (0, 0.01, 0.02 ,0.03, 0.04 ,0.05 ,0.07 and 0.1 wt%). The particles sized of TiO2,Al2O3 are about 20–50 nm.Epoxy resin and nano composites containing different shape nano fillers of (TiO2:Al2O3 composites),are shear mixing with ratio 1 to 1,with different nano hybrid fillers concentrations( 0.025 ,0.0 5 ,0.15 ,0.2, and 0.25 wt%) to Preparation of epoxy/ TiO2- Al2O3 hybrid composites. The mechanical properties of nanocomposites such as bending ,wearing, and fatigue are investigated as mechanical properties.
This study evaluates the performance of magnetic abrasive finishing (MAF) of aluminum alloy in terms of achieving materials removal (MR). A vertical milling machine is used to perform the finishing process using a developed MAF unit that consists of an inductor made out of a 150 mm long and 20 mm diameter iron core wound with 1500 turns and 0.5 mm copper wire. The commutator and magnetic pole are attached at the top and bottom of the inductor, respectively. The required current is supplied using a DC power supply. The South Pole workpiece is a 100×50×3 mm3 plate of AA 1100 aluminum alloy, whereas the magnetic pole represented the North Pole. Pole rotational speed, applied current, and abrasive finishing time was selected as
... Show MoreBackground The application of nanotechnology to biomedical surfaces is explained by the ability of cells to interact with nanometric features. The aim of this study was to consider the role of nanoscale topographic modification of CPTi dental implant using chemical etching method for the purpose of improving osseointegration. Materials and methods: Commercial pure titanium rod was machined into 20 dental implants. Each implant was machined in diameter about 3mm, length of 8mm (5mm was threaded part and 3mm was flat part). Implants were prepared and divided into 2 groups according to the types of surface modification method used: 1st group (10 implant) remained without nano surface modification (control), 2nd group include (10 implant) etche
... Show MoreThe 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 change in the size of the droplets during the pesticide application process could have a negative impact on the percentage of drift or the losses of pesticides to the environment. One of the factors that could affect the droplet size produced from a single nozzle is the internal design of the nozzle itself, in addition to the wear of the nozzle orifice as a result of the usage time. In this research, three types of nozzles with different internal designs were used (Turbo TeeJet (TT), Turbo TwinJet (TTj 6011003), and Drift Guard (DG 11003)). The nozzles were subjected to an accelerated wear test for one hundred hours, and different droplet size parameters (Dv 0.1, Dv 0.5, Dv 0.9),
The 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.