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
Microwave heating is caused by the ability of the materials to absorb microwave energy and convert it to heat. The aim of this study is to know the difference that will occur when heat treating the high strength aluminum alloys AA7075-T73 in a microwave furnace within different mediums (dry and acidic solution) at different times (30 and 60) minutes, on mechanical properties and fatigue life. The experimental results of microwave furnace heat energy showed that there were variations in the mechanical properties (ultimate stress, yielding stress, fatigue strength, fatigue life and hardness) with the variation in mediums and duration times when compared with samples without treatment. The ultimate stress, yielding stress and fatigue streng
... Show MoreAbstract. In this scientific work, we investigate the problem of the practical necessity of achieving the adequacy of translation activities with active translation from Russian into Arabic in various fields of translation. Based on the material of the latest suffix vocabulary, a serious attempt is made to clarify and specify the rules for the development of translator's intuition when translating from Russian into Arabic and vice versa. Based on the material collected by the latest suffix vocabulary, we try to make an attempt to reveal the role of suffix word creation in highlighting the general rules for achieving translation equivalence. The paper examines the process of creating words in multi-family languages, the difference between th
... Show MoreBackground The appropriate disposal of medication is a well-recognized issue that has convened growing recognition in several contexts. Insufficient awareness relating to appropriate methods for the disposal of unneeded medicine may result in notable consequences. The current research was conducted among the public in Iraq with the aim of examining their knowledge, attitude, and practices regarding the proper disposal of unused and expired medicines. Methods The present study used an observational cross-sectional design that was community-based. The data were obtained from using an online questionnaire. The study sample included people of diverse genders, regardless of their race or occupational status. The study mandated that all pa
... Show MoreBipedal robotic mechanisms are unstable due to the unilateral contact passive joint between the sole and the ground. Hierarchical control layers are crucial for creating walking patterns, stabilizing locomotion, and ensuring correct angular trajectories for bipedal joints due to the system’s various degrees of freedom. This work provides a hierarchical control scheme for a bipedal robot that focuses on balance (stabilization) and low-level tracking control while considering flexible joints. The stabilization control method uses the Newton–Euler formulation to establish a mathematical relationship between the zero-moment point (ZMP) and the center of mass (COM), resulting in highly nonlinear and coupled dynamic equations. Adaptiv
... Show MoreAbstract
Nowadays, the adoption of economic unity on the accuracy of financial reporting is very important. Economic units need accurate financial reporting to be more competitive and to improve the performance. Management can also achieve financial information in real time through the application of ERP systems. This system will facilitate management to access the most up-to-date information such as planning, monitoring and evaluating the business processes of the organization to be more effective.
On the practical side, the Enterprise Resource Planning (ERP) system was applied to the General Company for Vegetable Oils to demonstrate a course in enhancing the accuracy of financial reporting.
... Show MoreThanks allah and peace be upon our prophet muhammed and upon his family and his
followers……
The name is only called by the Almighty, One of the Names of the Creator Deity
features and slavery. He is the idol who worshiped.
The creator is derived from the creation of a sophisticated and significant from create Aharaz
for crust, and tailor the gown and the end of launch on God's creation of the creature, and this
release was a matter of metaphor One of the names of Allah, God is the creator himself is not
a partner Creator of all things, is the one who created
man from Nothingness began creating Adam peace be upon him and that he has passed the
stages in the process of creation, namely: He created him from du
As the major role of oil sector in financing and development of Iraqi economy this study tried to research on the factors which influencing the future of oil production in Iraq and for that study addressed the hypothesis (the production and export of crude oil in Iraq , influenced by many factors divided into internal and external factors this factors shared the effect varies in the size of their participation and runs from different sectors economic , political and social , in order to test the study hypothesis study addressed the subject of three axes(an overview of the history and facts of crude oil production in Iraq and factors internal Affecting the future of oil production in Iraq and external factors affecting the future
... Show MoreThe methodology of the concept of sovereignty in contemporary Islamic thought
The abdominal nerve cord of some species of Iraq Carabids has been studied to evaluate
the variation in the number of the abdominal ganglia among the species and to find out
relation of these variations with the classical taxonomy of the family Carabidae into tribes.