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The effect of composite bonding spot size and location on the performance of poly-ether-ether-ketone (PEEK) retainer wires
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Background: Poly-ether-ether-ketone(PEEK) has been introduced to many dental fields. Recently it was tested as a retainer wire‎ following orthodontic treatment. This study aimed to investigate the effect of changing the bonding spot size and location on the performance of PEEK retainer wires. Methods: A biomechanical study involving four three-dimensional finite element models was performed. The basic model was with a 0.8 mm cylindrical cross-section PEEK wire, bonded at the center of the lingual surface of the mandibular incisors with 4 mm in diameter composite spots. Two other models were designed with 3 mm and 5 mm composite sizes. The last model was created with the composite bonding spot of the canine away from the center of the crown, closer to the lateral incisor. The linear displacement of the teeth, strains of the periodontal ligament, and stresses in PEEK wire and composite were evaluated. The data was numerically produced with color coded display by the software. Selected values were tabulated and compared among models. Results: The amount of linear displacement and strain was very low. Stresses in the wire and composite were affected by the size and position of the composite bonding spot. The safe limits were identified at 235 MPa for PEEK and 100 MPa for composite. The basic model had a von Mises stress in the PEEK wire of 122.09 MPa, and a maximum principal stress in the composite of 99.779 MPa. Both stresses were within the safe limits, which means a lower risk of failure in PEEK and composite. All other models had stresses that exceeded the safe limit of the composite. The 3 mm composite model was the only one that developed stresses in the wire more than the safe limits of PEEK. Conclusions: Within the limitations of this study, bonding PEEK wires with 4 mm bonding spots to the clinical crown center provided the best mechanical performance of the wires and spots; otherwise, the mechanical properties of the wire and composite would be affected and, therefore, might affect the retention process. Keywords: Retention, PEEK, Finite element analysis

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Publication Date
Thu Jan 01 2009
Journal Name
Al-anbar Medical Journal
The Role of Epineurotomy in Carpal Tunnel Syndrome
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Aim: The purpose of this study is to compare the effect of epineurotomy of median nerve with just division of the transverse carpal ligament in the treatment of carpal tunnel syndrome. Patients & Methods: We conducted a prospective, random study to evaluate the effect of epineurotomy on the outcome of operative treatment of established median-nerve compression in the carpal canal. Fifty hands (forty-four patients) were selected randomly into two groups: group I had a release of the transverse carpal ligament alone, and group II had a release and adjuvant epineurotomy of the median nerve. The groups were similar with regard to age group, gender, duration of symptoms, and preoperative physical findings. All patients had electrophysiological e

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Publication Date
Mon Jan 28 2019
Journal Name
Journal Of The College Of Education For Women
The Authority Concept among University students of Baghdad
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The Present study aims to shed some light on the concept of authority of university students and to find statistically significant differences as regards this concepts in accordance with three variables gender (males, females),field of study(scientific ,humanities)and grade(second ,fourth). To accomplish the study a ( 7) level scale was developed for the concept of authority and it subjected to validity and credibility the scale was used with 590 student sample (237) males and (353) females Results show that male students show obedience to authority forms below the Avery e component with the theoretical Avery of the scale besides ,reinforcement was on the top of authority chain ,followed by person traits ,friends, affect punishment and t

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Publication Date
Mon Jul 01 2024
Journal Name
Journal Of Dentistry
The precision of drill calibration for dynamic navigation
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Objectives To quantify the reproducibility of the drill calibration process in dynamic navigation guided placement of dental implants and to identify the human factors that could affect the precision of this process in order to improve the overall implant placement accuracy. Methods A set of six drills and four implants were calibrated by three operators following the standard calibration process of NaviDent® (ClaroNav Inc.). The reproducibility of the position of each tip of a drill or implant was calculated in relation to the pre-planned implants’ entry and apex positions. Intra- and inter-operator reliabilities were reported. The effects of the drill length and shape on the reproducibility of the calibration process were also investig

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Publication Date
Mon Dec 05 2022
Journal Name
Baghdad Science Journal
Study the Nuclear Structure of Some Cobalt Isotopes
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The nuclear structure of some cobalt (Co) isotopes with mass number A=56-60 has been studied depending on the effect of some physical properties such as the electromagnetic properties effects, such as, elastic longitudinal form factors, electric quadrupole moments, and magnetic dipole moments. The fp model space is used to present calculations using GXFP1 interaction by adopting the single particle wave functions of the harmonic oscillator. For all isotopes under consideration, the 40Ca nucleus is regarded as an inert core in fp model-space, while valence nucleons are moving through 1f7/2, 2p3/2, 1f5/2, and 2p1/2 orbits. The effects of core-polarization are obtained by the first orde

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Publication Date
Sun Oct 01 2017
Journal Name
Journal Of Educational And Psychological Researches
Obstacles to development in the field of education
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Education is the most powerful and important weapon in fighting poverty and unemployment because it provides students with new skills that appropriate the new market requirements and fair distribution of natural resources. It also transfers knowledge, skills, and ethics over generations. Education aims to create effective leaders who go under training and rehabilitation process, create a new human and instill faith, generate the creativity and innovation, and keep abreast with scientific process, updating curriculum, and finally, applying the technical education

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Publication Date
Fri Feb 02 2018
Journal Name
International Journal Of Science And Research (ijsr)
The Compressibility of Clayey Soils Reinforced with Fiberglass
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During the prior three decades numerous research works presented to investigate the behavior of reinforced soil. A, IJSR, Call for Papers, Online Journal

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Publication Date
Mon Oct 01 2018
Journal Name
Iraqi Journal Of Physics
The study of nuclear structure for some nuclei
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 An analytical form of the ground state charge density distributions
for the low mass fp shell nuclei ( 40  A  56 ) is derived from a
simple method based on the use of the single particle wave functions
of the harmonic oscillator potential and the occupation numbers of
the states, which are determined from the comparison between theory
and experiment.
For investigating the inelastic longitudinal electron scattering form
factors, an expression for the transition charge density is studied
where the deformation in nuclear collective modes is taken into
consideration besides the shell model space transition density. The
core polarization transition density is evaluated by adopting the
shape of Tass

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Publication Date
Wed Jan 01 2020
Journal Name
Italian Journal Of Pure And Applied Mathematics
The non-zero divisor graph of a ring
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Publication Date
Mon Dec 24 2018
Journal Name
Bulletin Of The Iraq Natural History Museum
REVISION OF THE FAMILY CHLOROPIDAE (DIPTERA) IN IRAQ
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Publication Date
Sun Jul 01 2018
Journal Name
Journal Of Craniofacial Surgery
Surgical Management of the Recent Orbital War Injury
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