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
The method of Similarity of important topics in Arabic Rhetoric has ample evidence in the Qur'an and the Hadith and the words of the Arabs and this study is limited to only the Koran.
There have been Similarity in the Holy Quran on both types : investigative and discretion , but the verses are more Similarity investigative and in verse 49 Similarity investigative and in verse 25.
The rush of Albulageyen and many other examples of Quranic Vmtheloa on Similarity , with a linguistic analysis and return to the origins of the meanings are not properly counted Similarity , Kolvaz cunning , deception , and maliciousness , the bad and ridicule.
This study seeks as much as possible to the statement of this phenomenon and stand on these t
I often read in Islamic jurisprudence in all chapters as much as possible from divine success, time and health, and everything I read in any of the chapters of jurisprudence, I see divine light, eternal wisdom, and a constitution that does not accept error and alteration, as I looked at the great jurisprudential treasures and this enormous wealth, A person finds in himself helplessness in front of this law, how clear, easy, and accurate it is, and it contains permanent good for man, as it is a religion of mercy, benevolence, and goodness, and among these chapters of jurisprudence is the jurisprudence of the commandment. Of the reasons, in the will, the person has had the opportunity to make up for what he missed of doing good that a pers
... Show MoreThere is an association between the signifier and the signifier. This association shows the eyeball, which acquires a direct presence and whose presence influences the level of production of the hidden connotation. Because the theatrical presentation is a series of auditory-visual functions, these signs are looking for the exploration of their meanings and their evocation to form a complete loop to achieve the association of the above. This is what made the researcher to monitor the abundance of semantic shifts in theatrical presentation as long as the implications of the strategy continue in the game of semantic production with multiple horizons, and the idea in theatrical presentation tolerates multiple readings according to the refere
... Show MoreIn our research, we introduced new concepts, namely *and **-light mappings, after we knew *and **-totally disconnected mappings through the use of -open sets.
Many examples, facts, relationships and results have been given to support our work.
كان لنهاية الحرب الباردة وعولمة العالم على وفق رؤية كونية تتجاوز حدود ومفاهيم السيادة الوطنية والقومية الاثر الواضح في ترتيب العلاقات الدولية , واصبحت تلك العلاقات تدور حول محورين الاول .. هو الاعتماد المتبادل بين الدول من اجل الوصول الى خطوط مشتركة للمصالح المختلفة بين هذه الدول . والآخر.. هو تبعية الدول الضعيفة للدول القوية لافتقار الاولى توفير الحاجيات الى مواطنيها . هذا يشير الى نشأة علا
... Show MorePraise be to God, Lord of the worlds, and prayers and peace be upon our master Muhammad and upon his family and companions.
We see human societies differ from one society to another in organizing social life, and each according to the foundations and rules prepared by the main thing in the welfare and prosperity.
That is why we see eastern societies differ from western societies in many patterns and various ways of reaching that sophistication, until Islam came and gave the proper model in raising society at that time to the best and highest social levels, because it is based on heavenly rules and foundations and not status as in previous civilizations.
And when the Islamic community has
Many urban and rural areas fall under the impact of disasters, whether natural or industrial, and with increasing complexity in urban areas, with diversity of economic, social and political components, and technological and cognitive development, the effects of disasters and wars have increased with the time, where disasters are affecting all aspects of life, causing great waste of property and lives, also displacement of populations and disruption of economic life, these effects are multiplied if they are not dealt with in sound curricula and scientific strategies.
The research aims to identify the experiences of some countries and their strategies and effective programs in reconstruction after exposure to disasters and wars wit
... Show MoreThe current study included the collection of 175 samples (blood-urea) of patients suffering from rheumatism, collected from Baghdad Teaching Hospital (Educational Laboratory), Al-Kindy Teaching Hospital, Al-Imamian Al-Kadhimya in Medical City in Baghdad at different duration between 2016/10/1-2017/2/1. The bacterial growth results showed that 80% of urea samples positive for bacterial culture, while the rate of samples did not show any bacterial grow this 20%. The isolation subjugates to morphological, microscopically and biochemical tests, as also diagnosis by Api system. The most frequent bacterial pathogenic is E. coli which appeared highly rate (41.97)% followed by E. cloacae (21.25)%, P. aeruginosa (12.5)%, Salmonella (10)% and the pro
... Show MoreThe present study examines the main points of differences in the subject of greetings between the English language and the Arabic language. From the review of the related literature on greetings in both languages, it is found that Arabic greeting formulas are more elaborate than the English greetings, because of the differences in the social customs and the Arabic traditions and the Arabic culture. It is also found that Arabic greetings carry a religious meaning basing on the Islamic principle of “the same or more so”, which might lead to untranslatable loopholes when rendered in English.