Preferred Language
Articles
/
nRcsno0BVTCNdQwCxBbn
The effect of composite bonding spot size and location on the performance of poly-ether-ether-ketone (PEEK) retainer wires
...Show More Authors

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

Scopus Crossref
Publication Date
Thu Feb 01 2018
Journal Name
European Journal Of General Medicine
The Value of Longitudinal Strain versus Coronary Angiography in Detection of Coronary Artery Disease
...Show More Authors

Aims: The aim of this study was to evaluate the value and accuracy of longitudinal strain in detection of coronary artery disease compared to coronary angiography. Results: The left ventricular longitudinal strain-speckle tracking showed evidence of stenosis of left anterior descending artery, circumflex artery and right coronary artery in (86.1%), (76.4%), and (84.7%) respectively. For the stenosis in left anterior descending artery, the current study showed that the longitudinal strain was a good predictor for presence of significant stenosis with a sensitivity of (93.8%), specificity (75%) and accuracy (91.7%) compared with coronary angiography. For the stenosis in right coronary artery, the left ventricular longitudinal strain had

... Show More
View Publication
Crossref (2)
Crossref
Publication Date
Sun Apr 07 2013
Journal Name
Journal Of Educational And Psychological Researches
The Sources of psychological Stress with students living at dormitories in university of Baghdad.
...Show More Authors

Stress with all its kinds are the results of a nick development Leading to delinquency burdening the ability of people.. development gas its effect on self and body reflecting on health ( physically, Psychological. And mentally) and finally leading to death (Al emara,2001,2).

Stress refers to he degree of response of the individual to events and environmental changes in his daily life with their physiological effects  such as headaches , backaches, and gastric ulcer that have different effect depending on the personality of the person and his psychological characteristics differences airing individuals ( Al emirs, zool,2  )

The aims:

  • knowi

... Show More
View Publication Preview PDF
Publication Date
Sun Sep 06 2009
Journal Name
Baghdad Science Journal
Extension of the Chebyshev Method of Quassi-Linear Parabolic P.D.E.S With Mixed Boundary Conditions
...Show More Authors

The researcher [1-10] proposed a method for computing the numerical solution to quasi-linear parabolic p.d.e.s using a Chebyshev method. The purpose of this paper is to extend the method to problems with mixed boundary conditions. An error analysis for the linear problem is given and a global element Chebyshev method is described. A comparison of various chebyshev methods is made by applying them to two-point eigenproblems. It is shown by analysis and numerical examples that the approach used to derive the generalized Chebyshev method is comparable, in terms of the accuracy obtained, with existing Chebyshev methods.

View Publication Preview PDF
Crossref
Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Evaluation of the one electron expectation values for different wave function of Be atom
...Show More Authors

The aim of this work is to evaluate the one- electron expectation value from the radial electronic density function D(r1) for different wave function for the 2S state of Be atom . The wave function used were published in 1960,1974and 1993, respectavily. Using Hartree-Fock wave function as a Slater determinant has used the partitioning technique for the analysis open shell system of Be (1s22s2) state, the analyze Be atom for six-pairs electronic wave function , tow of these are for intra-shells (K,L) and the rest for inter-shells(KL) . The results are obtained numerically by using computer programs (Mathcad).

View Publication Preview PDF
Crossref
Publication Date
Thu Aug 14 2025
Journal Name
Journal Of Administration And Economics
Using dynamic Fuzzy programming to control the storage of some Department of Commerce stores
...Show More Authors

In this research was to use the method of classic dynamic programming (CDP) and the method of fuzzy dynamic programming (FDP) to controlling the inventory in N periods and only one substance ,in order to minimize the total cost and determining the required quantity in warehouse rusafa principal of the ministry of commerce . A comparison was made between the two techniques، We found that the value of fuzzy total cost is less than that the value of classic total cost

View Publication
Publication Date
Thu Jan 01 2015
Journal Name
Journal Of Faculty Of Medicine Baghdad
Outcome of buccal mucosal patch graft in the Management of recurrent hypospadias urethrocutaneous fistula
...Show More Authors

Background: urethrocutaneous fistula after hypospadias surgery repair is the most common complication and remains a frustrating problem for surgeon and the patient. The problem is exacerbated because the urethrocutaneous fistula may recur which adds more demands surgery. Objectives: The purpose of this study is to evaluate of the use of oral mucosal graft for management of recurrent urethrocutaneous fistula after hypospadias repair. Patients and Methods: twelfth patients with age ranging from 4 year to 15 years were presented with history of recurrent fistula. Most of fistula were located in proximal penile and penoscrotal region (58.3%) . those patients were repaired by using oral mucosal graft with mean postoperative follow up period up t

... Show More
Publication Date
Sun Jan 24 2016
Journal Name
Al-academy
The effectiveness of pantomime in development of movement skills for Kindergarten: محمد إسماعيل الطائي
...Show More Authors

In order to a chive the aim of the research the researcher chose the (Nebras kindergarten) to be the search sample .the member of the sampleFrom(males and fameless)and the researcher chose the class of(butterfly) as experimental group to do the pantomime consist of(15)males and fameless, and put(singles, senses ,double senses and communal senses)in the binging of the experiment the researcher applied the measurement of(AL Kaswany and other)as(pre_ test)which prepare to measure, the movement skills for kindergarten, the measurement have the validity and reliability to knowledge the difference between the two experiment. The experiment continue from(20/1/201to 20/2/2014)in the end of experiment the researcher applied the measurement of(AL

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Jun 01 2020
Journal Name
Iraqi Journal Of Physics
A Calculation real abundance of gaseous elements of the comet PanSTARRS C/2011 S4
...Show More Authors

    X-ray emission contains some of the gaseous properties is produced when the particles of the solar wind strike the atmosphere of comet ISON and PanSTARRS Comets. The data collected with NASA Chandra X-ray Observatory of the two comets, C/2012 S1 (also known as Comet ISON) and C/2011 S4 (Comet PanSTARRS) are used in this study.

   The real abundance of the observed X-ray spectrum elements has been extracted by a new simple mathematic model. The study found some physical properties of these elements in the comet’s gas such as a relationship between the abundance with emitted energy. The elements that have emission energy (2500-6800) eV, have abundance (0.1-0.15) %, while the elements

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Jul 01 2003
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
DESCRIPTION OF THREE NEW SPECIES OF THE GENUS ANTHRENUS GEOFFORY (COLOEOPTERA, DERMESTIDAE) FROM IRAQ
...Show More Authors

The present work represents description of three new species of genus Anthrenus
Geoffory from Iraq, these are : A. aradensis sp. nov., A. fabrici sp. nov. and A.
unicolor sp. nov. Locality, host plants and date of collection were given.

View Publication Preview PDF
Publication Date
Thu Jun 30 2016
Journal Name
Al-kindy College Medical Journal
Evaluating the Students Perception of Academic Learning Environments in AL-Kindy Collage of Medicine
...Show More Authors

Background: Educational environment is one of the most important determinants of an effective curriculum. Students' perceptions of their educational environment have a significant impact on their behavior and academic progress. Objective: 1. To identify students’ perception to the educational environment.2. To identify any gender or class level differences in the students’ perception.Type of the study: This is a descriptive cross-sectional studyMethodology: The study was carried out on convenient sample of 150 students of 2nd and 5th grade. This study was done in Al Kindy Medical College, Baghdad, Iraq and conducted during the period from the 1st of October 2013 till the end of March 2014, by using DREEM questionnaire a validated uni

... Show More
View Publication Preview PDF