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.
The cytotoxic effect of different concentrations of Crude extracts of Solanum melongena , Curcuma longa and Daucus carota on mice mammary adenocarcinoma cell line was studied . The concentrations used were 62.5 125 , 250, 500 Microgram/militer for 24,48 and 72 hour . These exracts were prepared by using alcoholic and hot water methods . The preliminary chemical tests revealed acidic pH of all extracts. The results showed a clear toxic effect of all extracts in a time and dose –dependent manner . The Curcuma longa had the highest effect on adenocarcinoma 94.61% , followed by Solanum melonga( 93.20%) and the lowest effect was by Da
... Show MoreBackground: Adjustment of any premature occlusal contact of any zirconia restoration requires its polishing or glazing in order to restore the smoothness of the restoration. The objective of this in vitro study was to evaluate the effects of different polishing systems and glazing on the surface roughness of full-contour zirconia. Material and methods: Forty disks (diameter: 8 mm, thickness: 6.4 mm) were prepared from pre-sintered full-contoured zirconia block; they were colored and sintered in a high-temperature furnace at 1500ËšC for 8 hours. The specimens were then leveled and finished using grinding and polishing machine and adjusted using diamond disk. The specimens were then randomly divided into four groups (n=10), group I involves
... Show MoreIn this study, the effect of the thermal conductivity of phase change material (PCM) on the performance of thermal energy storage has been analyzed numerically. A horizontal concentric shell-and-tube latent heat thermal energy storage system (LHTESS) has been performed during the solidification process. Two types of paraffin wax with different melting temperatures and thermal conductivity were used as a PCM on the shell side, case1=0.265W/m.K and case2=0.311 W/m.K. Water has been used as heat transfer fluid (HTF) flow through in tube side. Ansys fluent has been used to analyze the model by taking into account phase change by the enthalpy method used to deal with phase transition. The numerical simulatio
... Show MoreIn this research the electrical conductivity measurements were made on the amorphous InAs films prepared by thermal evaporation method in thickness 450 nm and annealed in different temperatures in the range (303- 573) K. The electrical conductivity (σ) showed a decreasing trend with the increasing annealing temperature, while the activation energies (Ea1, Ea2) showed an opposite trend, where the activation energies are increased with the annealing temperature.
Background: The aim of the study was to investigate the effect of surface treatments of zirconia (grinding and sandblast with 50μm, 100 μm) on shear bond strength between zirconia core and veneering ceramic. Material and methods: Twenty-eight presintered Y-TZP ceramic specimens (IPS e.max ZirCAD, Ivoclar vivadent) were fabricated and sintered according to manufacturer’s instructions. The core specimens were divided randomly in to 4 groups, group 1: no surface treatment, group2: zirconia specimens were ground with silicon carbide paper up to1200 grit under water cooling, group3: zirconia specimens were ground and sandblast with 100 μm alumina, group 4: zirconia specimens were ground and sandblast with 50 μm alumina. Surfa
... Show MoreThis research involves studying the influence of increasing the
number of Gaussian points and the style of their distribution, on a circular exit pupil, on the numerical calculations accuracy of the point spread function for an ideal optical system and another system having focus error of (0.25 A. and 0.5 A. )
It was shown that the accuracy of the results depends on the type of
distributing points on the exit pupil. Also, the accuracy increases with the increase of the number of points (N) and the increase of aberrations which requires on increas (N).
Background: Diabetes mellitus (DM) causes damaging effects on the cardiac function; these effects can be observed on the diastolic performance of the heart reflected on the change in transmitral blood velocity, the cardiac wall and septum thickness.
Objectives: The present study was to assess the diastolic and systolic cardiac muscle performance for patients with type 2 diabetes mellitus compared with control individuals and to evaluate the index of myocardial performance.
Patients and Methods: The study involved 97 patients (35 male and 62 female of average age of 56.2 ±10.755) of type 2 diabetes mellitus (DM), they were investigated for their left ventricle performance and compared with 51 normal in
This study aims to evaluate the effect of low power a semi-conductor He-Ne laser 4 mw power with 635 nm length on the growth and cell viability of dermatophyte Trichophyton mentagophytes. For this study, skin samples of 22 patents were collecting; those patients were suffering from dematophytsis caused by the dermatophytes, three isolates were diagnosed in dermatophytes group were T. mentagophytes. Results showed that rays of semi-conductor laser with 635 nm wavelength of 4 mn power have affected the fungal growth T. mentagophytes (the ideal isolates) in sold media when exposed to laser radiation in different periods of 10-20 second duration, but the other two isolates gave negative results. The effects of He-Ne laser rays in dry w
... Show MoreThis study has been conducted to examin the effect of potassium sorbate at different level of 0.03,0.06,0.10% on the number of bacteria and mold and to extend the storage life of laboratory processed biscuit. The results indicated that the use of 0.03% potassium sorbate prolonged the storage peroid until the third month .three types of bacteria has been isolated from processed biscuit, namely, Staphylococcus aureus, Bacillus cereus, Esherichia coli using 0.06% potassium sorbate showed no growth of bacteria up to six month of storage ,while using of 0.03% and 0.06% potassium sorbate prevent the growth of mold up to three and six months of storage respectively. Both Aspergillus and Penicillium were isolated from the processed biscuit.
An isolate of Leishmania major was grown on the semisolid medium and incubated at 26ºC. The isolate was irradiated by He: Ne laser (632.8 nm, 10 mW) at exposure times (5, 10, 15, 20, 25, 30) minutes in their respective order. The unirradiated groups represent control group. Growth rate and percentage of viability were examined during six days after irradiation. The change in these two parameters reflects the effect of irradiation on the parasite. The results refers that the general growth effected by irradiation in comparison with un irradiation group, The growth rate of parasite decrease with increasing the exposure time in comparison with control group. Parasite viability decrease with irradiation and the percentage of living cell dec
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