Background: The present study was conducted to evaluate the effects of different bleaching methods on the shear bond strength of orthodontic Sapphire brackets bonded to human premolars teeth using light cured composite resin and to determine the predominant site of bond failure. Materials and Methods: Thirty freshly extracted human premolars were selected and randomly divided into three groups (10 per group). These groups are: control (unbleached) group, hydrogen peroxide group (HP) 37.5% ; which is the in- office bleaching method group, carbamide peroxide group (CP) 16%; which is the at- home bleaching method group. After bleaching process was performed, all the teeth stored in distilled water in a sealed container at room temperature for 24 hours before bonding was initiated, then orthodontic brackets were bonded with a light cure composite resin, stored in distilled water at room temperature for another 24 hours before debonding then the brackets de-bonded and tested for shear bond strength using an Instron universal testing machine. For adhesive remnant index (ARI) the enamel surface and bracket base of each tooth were inspected under magnifying lens (20X) of a stereomicroscope. Results and Conclusions: Non-statistically significant differences of shear bond strengths were found between the control group and the bleached groups, the dental bleaching in both methods did not affect the SBS of Sapphire brackets. The mode of failure was mostly between the adhesive and the enamel and the bond failure between the bracket base and the adhesive were also observed. Keywords: Shear bond strength, tooth bleaching agents, orthodontic brackets, dental bonding.
The concept of privatization is built on the basis of the transfer of assets and services of the public sector to the private sector this concept has appeared in the eighties of the last century whene the high oil prices took place and recession solution swept the world Which called for the freedom of the market and left the room for the private sector to take the initiatine in economic activity. Both the IMF have adopted this thesis in their programs of the structural adjustment in light of external and internal factors helped to Create the conditions to accept thesis that under the pretext of achieving a number of economic goals.
In Iraq in spite of
... Show MoreSummery of the Study: The Israeli interest in Iraq was not the result of the 2003 US war, which ended with its occupation, but Iraq was still at the top of Israeli concerns, as it was due to its interest and desire to occupy the Zionist movement for a number of reasons, most importantly its religious position in the Jews and control It is a sacred religious duty, so Israel has employed all its organs, institutions, relations and espionage networks in order to penetrate it and perpetuate its existence, and succeeded in achieving its foreign policy objectives at a time when the area was open to it without opposition or competition thanks to its strategic alliance with the states Of the United States of America, which has been able to penet
... Show MoreAcromegaly is a rare disease produce generalize and serious alteration in the patient with active disease. Many of these patients are also diabetic. Many analytes, hormones, markers are change in these disease. The objective of study is to assess the modification in a number of parameters that changed during the acromegaly as a result of excess in GH and IGF1 levels. The study included 36 patients and 38 healthy controls, paired by sex and age and BMI. Serum concentration of GH and the other parameters including (insulin, glucose, lipid profile, uric acid ) were determined by biochemical method .Compared to controls, acromegalic patients had increased levels of GH, insulin, glucose, triglyceride, very low density lipoprotein(VLDL) (p<0.05)
... Show MoreBackground: Pyogenic discitis most frequently occurs
after home delivery, hemorridectomy, and dilatation and
curettage. Discitis is generally due to blood borne bacterial
invasion of the disc from adjacent end-plate via
communicating vessels. Infective discitis remains an
uncommon, but potentially serious cause for back pain.
Delayed diagnosis can occur and a high index of suspicion
may occur.
Methods: The study included 30 patients suffering from
localized low back pain with limitation of movement.
Diagnosis was made by history, physical examination and
investigation mainly E.S.R and MRI.
Results: 50.3% of patient with discitis had a history of
vaginal delivery, 15% had a history of hemorridectomy
The research article deals with the process of building or rebuilding the state in Iraq after 2003 in its various dimensions, in light of the vision and foundational procedures that were developed and supervised by the United States in cooperation with the new leaders of Iraq based on the mechanism of sectarianethnic representation, and diagnosing the imbalances that arose out of that vision and the accompanying procedures, which led to the emergence of new variables in the political process, especially in the post-ISIS* phase, which produced important challenges to the political system and the Iraqi state. The political dynamics and balances emerging after ISIS* represented at the same time opportunities and risks in the process of
... Show MoreBackground: The insertion torque (IT) values and implant stability quotient (ISQ) values are the measurements most used to assess primary implant stability. This study aimed to assess the relationship between ISQ values and IT. Materials and methods: This study included 24 patients with a mean (SD) age of 47.9 (13.64) years (range 25-75 years). The patients received 42 dental implants (DI), 33 in the mandible and 9 in the maxilla. The DI were installed using the motorized method with 35 Ncm torque, When DI could not be inserted to the requisite depth by the motorized method, a hand ratchet was used and the IT was recorded as ˃ 35 Ncm. Implant stability was measured utilizing Osstell® ISQ. The secondary stability was measured after 16
... Show MoreThe conception and experimental assessment of a removable friction-based shear connector (FBSC) for precast steel-concrete composite bridges is presented. The FBSC uses pre-tensioned high-strength steel bolts that pass through countersunk holes drilled on the top flange of the steel beam. Pre-tensioning of the bolts provides the FBSC with significant frictional resistance that essentially prevents relative slip displacement of the concrete slab with respect to the steel beam under service loading. The countersunk holes are grouted to prevent sudden slip of the FBSC when friction resistance is exceeded. Moreover, the FBSC promotes accelerated bridge construction by fully exploiting prefabrication, does not raise issues relevant to precast co
... Show MoreThe study presents the test results of Completely Decomposed Granite (CDG) soil tested under drained triaxial compression, direct shear and simple shear tests. Special attention was focused on the modification of the upper halve of conventional Direct Shear Test (DST) to behave as free
head in movement along with vertical strain control during shear stage by using Geotechnical Digital System (GDS). The results show that Free Direct Shear Test (FDST) has clear effect on the measured shear stress and vertical strain during the test. It has been found that shear strength
parameters measured from FDST were closer to those measured from simple shear and drained triaxial compression test. This study also provides an independent check on
This study investigated the shear performance of concrete beams with GFRP stirrups vs. traditional steel stirrups. Longitudinal glass fiber‐reinforced polymer (GFRP) bars were used to doubly reinforce the tested beams at both the top and bottom of their cross sections. To accomplish this, several stirrup spacings were provided. Eight beam specimens, measuring 300 × 250 × 2400 mm, were used in an experimental program to test under a two‐point concentrated load with an equal span‐to‐depth ratio until failure. Four beams in Group I have standard mild steel stirrups of 8 mm diameter, while four beams in Group II have GFRP stirrups with the same adopted diameter. The difference betwe