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
Since the invention of the automobile, no aspect of American life, including crime and its control, has remained untouched by this far-reaching innovation in transportation. Vehicular "hot pursuit"-when suspects in motor vehicles use excessive speed in attempting to elude the police. Unfortunately, accounts of wild chases across crowded inner city streets, through tree-lined suburban boulevards, and over remote country roads are very real and not merely fictional material created for entertaining television and motion picture audiences. The specter of "hot pursuit," complete with screaming sirens and red or blue flashing lights, has become a recurring fact of modem life.1 So, too, are the mishaps involving police vehicles or the vehicles pu
... Show MoreThe present research aims at identifying the relationship between intuitive thinking and mental alertness. The researcher used two tools: the intuitive thinking scale built by the researcher and consists of (40) paragraphs fall under four alternatives, while the second tool is the mental alertness scale consists of (70) paragraphs that the researcher built, and was verified psychometric properties of the two scales of honesty After the collection of information and statistical processing, the researcher reached the following results: 1. The results showed that the students of the third stage / Faculty of Education enjoy intuitive thinking. 2. The results showed that the students of the third stage / Faculty of Education enjoy mental alertne
... Show MoreType 2 diabetes mellitus(T2DM) is a metabolic disease that is associated with an increased risk for atherosclerosis by 2-4 folds than in non- diabetics. In general population, low IGF-1 has been associated with higher prevalence of cardiovascular disease and mortality .This study aims to find out the relationship between IGF-1 level and other biochemical markers such as Homeostasis Model Assessment insulin resistance(HOMAIR) and Body Mass Index(BMI) in type 2 diabetic patients . This study includes (82) patients (40 females and 42 males) with age range (40-75) years,(34) non obese diabetic patients and (48) obese diabetic patients. The non obese individuals considered
... Show MoreComplexes of Au(III) ,Pd (II) , Pt (IV ) and Rh(III) with S – propynyle -2- thiobenzimidazole (BENZA) have been prepared and characterized by IR and UV- Visible spectral methods in addition to magnetic and conductivity measurements and micro – elemental analysis (CHN).The probable structures of the new complexes have been suggested.
The objective of the present work was to estimate water requirements and water use efficiency for Broccoli under normal irrigation conditions and sewage irrigation. Field experiment was carried out during the season 2018 at station/Sulaimni agricultural station/Bakrajo –College of Agricultural Sciences. The experiment included three treatments: River water irrigation in all season growth (I1), Sewage water irrigation in all season growth (I2), Alternate irrigation (one river irrigation followed by two sewage water irrigation) in all season growth (I3). The experimental Design was Randomized Complete Block Design (RCBD) w
Ursolic acid (UA, 3 ?-hydroxy-urs-12-en-28-oic acid) are isomeric triterpenic acids. The high quantities of pentacyclic triterpenoids in Scabiosa species seems to be obvious and there is an evidence that most of pentacyclic triterpenoids that have been isolated are saponins. This is one of the most important characteristic of the genus Scabiosa, the main aglycones are ursolic acid and oleanolic acid. In the current study, isolation from the aerial part and roots of Scabiosa palaestina L. was performed using Preparative HPLC. Furthermore, detection and quantitation of ursolic acid was performed by high performance thin layer chromatography (HPTLC). The identification of isolated triterpenoid involves two methods including FT-IR coupl
... Show MoreBackground: Chronic renal failure (CRF) is a clinical syndrome that occurs when there is gradual decline in renal operation overtime.
Objective: This study aims to investigate the prevalence of depression among medical students at university of Baghdad, college of medicine in Iraq and the association between some variables and depression.
Aim: This study aimed to identify the impact of tobacco use in the etiology of chronic renal failure among Sudanese patients in Omdurman Military Hospital and Omdurman Kidney Dialysis Center
Materials and methods: This descriptive community-based study was conducted in Khartoum State. A random sample of 100 cases with chronic renal failure and 100
... Show MoreThe current research aims to identify the contributions of small income-generating projects in theempowerment of rural women in Nineveh Governorate ,Al-Hamdaniya district, as a simplerandom sample was drawn from the research community of 280 respondents , according to theRobert Mason equation at the level of significance 0.05, so the sample size was 162 respondents,i.e. a percentage 58% collected the necessary data using a questionnaire prepared as a basic toolfor data collection consisting of 20 items distributed on two axes ,and the results of the researchwere analyzed and presented using the spss statistical program, as well as manual analysis usingrepetitions, the weighted mean, the standard deviation, and the percentage weight. And the
... Show MoreThe purpose of this research is to demonstrate the impact of banking compliance in combating money laundering and terrorist financing through banks. The phenomenon of money laundering and terrorist financing has received wide attention in the countries of the world and international organizations because of the negative effects this phenomenon has on the global economy as a result of exploiting developments and modern banking operations to pass Money laundering and terrorist financing operations in order to legitimize illegal funds and obliterate their criminal sources, which obliged the banking sector to increase control measures in order to reduce these operations, which conceal money laundering thr
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