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An evaluation of the influence of different finishing lines on the fracture strength of full contour zirconia CAD/CAM and heat press all-ceramic crowns
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ABSTRACT Background: One of the major problems of all ceramic restorations is their probable fracture against the occlusal forces. The objective of this in vitro study was to evaluate the effect of two gingival finishing lines (90°shoulder and deep chamfer) on the fracture resistance of full contour CAD/CAM and heat press all-ceramic crowns. Materials and Methods: Thirty two maxillary first premolars were prepared to receive full contour CAD/CAM (zolid) and heat press (Cergo Kiss) ceramic crowns using a special paralleling device (Parallel-A-Prep). The teeth were divided into four groups according to the type of finishing line prepared. Each crown was cemented to its corresponding tooth using self-etch, self-adhesive dual cure resin cement. Following storage for 1 week in distilled water at room temperature, teeth were subjected to thermal cycling. Fracture resistance was determined using a universal testing machine, and the samples were investigated microscopically from the point of view of the origin of the failure. Statistical analysis was carried out using the one-way ANOVA and Student’s t-tests. Results: The mean values of fracture resistance for CAD/CAM group showed 1367.250+178.967 N for 90°shoulder margins and 1109.250+252.455 N for the deep chamfer margins. ANOVA test results revealed high significance between and within the groups. The mean values of fracture resistance for heat press group were 548.562+272.471 N for 90°shoulder margins and 247.912+96.995 N for the deep chamfer margins expressing statistical significance. Conclusions: The results of this study pointed to a relationship between the design of the cervical finishing line and the fracture strength of the full CAD/CAM crowns and the full heat press ceramic crowns. Both 90° shoulder and deep chamfer finishing lines are suitable for zolid crowns while the 90° shoulder is more suitable for the Cergo Kiss crowns than the deep chamfer preparation. Key words: Full contour, All-ceramic crowns, CAD/CAM, Heat press, Fracture strength.

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Publication Date
Mon Jul 01 2019
Journal Name
Iop Conference Series: Materials Science And Engineering
On Estimation of the Stress – Strength Reliability Based on Lomax Distribution
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Abstract<p>The present paper concerns with the problem of estimating the reliability system in the stress – strength model under the consideration non identical and independent of stress and strength and follows Lomax Distribution. Various shrinkage estimation methods were employed in this context depend on Maximum likelihood, Moment Method and shrinkage weight factors based on Monte Carlo Simulation. Comparisons among the suggested estimation methods have been made using the mean absolute percentage error criteria depend on MATLAB program.</p>
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Publication Date
Thu Jun 15 2023
Journal Name
Jornal Of Al-muthanna For Agricultural Sciences
Effect of different levels of Adrenocorticotropic hormone (ACTH) on physiological performance of broiler under heat stress conditions.
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This experiment was holdup in A-Faris poultry farms from 1st March to 11 of Aprile 2019. (ACTH) hormone infusion was tested in this experiment on acid-base regulation in broiler chickens. For 7 days, osmotic pumps dispensed 8 IU of ACTH in saline/kg of BW/d, or the same volume of saline as in ACTH at 1 l/h. On days 0 and 14, after the beginning of the infusions, blood samples were obtained to establish a baseline. The plasma concentrations of Na+, K+, and Cl- were decreased, whereas the partial pressure of CO2, anion gap, corticosterone, mean corpuscular hemoglobin concentration, and blood concentrations of hemoglobin and HCO - were all elevated due to the ACTH administration. When given ACTH, neither blood pH nor plasma Ca2+ levels changed

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Publication Date
Tue Nov 01 2016
Journal Name
Journal Of Engineering
Experimental Investigations on the Strength and Serviceability of Biaxial Hollow Concrete Slabs
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Biaxial hollow slab is a reinforced concrete slab system with a grid of internal spherical voids included to reduce the self-weight. This paper presents an experimental study of behavior of one-way prestressed concrete bubbled slabs. Twelve full-scale one-way concrete slabs of (3000mm) length with rectangular cross-sectional area of (460mm) width and (150mm) depth. Different parameters like type of specimen (solid or bubbled slabs), type of reinforcement (normal or prestress), range of PPR and diameter of plastic spheres (100 or 120mm) are considered. Due to the using of prestressing force in bubbled slabs (with ratio of plastic sphere diameter D to slab thickness H, D/H=0.67), the specimens showed an increase in ultimat

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Publication Date
Sun Jan 01 2023
Journal Name
8th Engineering And 2nd International Conference For College Of Engineering – University Of Baghdad: Coec8-2021 Proceedings
Prediction of pore and fracture pressure using well logs in Mishrif reservoir in an Iraqi oilfield
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Publication Date
Fri Sep 01 2023
Journal Name
Iraqi Journal Of Physics
Influence of NiTi Spring Dimensions and Temperature on the Actuator Properties
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Nitinol (NiTi) is used in many medical applications, including hard tissue replacements, because of its suitable characteristics, including a close elastic modulus to that of bones. Due to the great importance of the mechanical properties of this material in tissue replacements, this work aims to study the hysteresis response in an attempt to explore the ability of the material to remember its previous mechanical state in addition to its ability to withstand stress and to obtain the optimal dimensions and specifications for the manufacturer of NiTi actuators. Stress-strain examination is done in a computational way using a mutable Lagoudas MATLAB code for various coil radii, environment temperatures, and coil lengths. The computational m

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Publication Date
Sun Jan 14 2018
Journal Name
Journal Of Engineering
Optical Character Recognition Using Active Contour Segmentation
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Document analysis of images snapped by camera is a growing challenge. These photos are often poor-quality compound images, composed of various objects and text; this makes automatic analysis complicated. OCR is one of the image processing techniques which is used to perform automatic identification of texts. Existing image processing techniques need to manage many parameters in order to clearly recognize the text in such pictures. Segmentation is regarded one of these essential parameters. This paper discusses the accuracy of segmentation process and its effect over the recognition process. According to the proposed method, the images were firstly filtered using the wiener filter then the active contour algorithm could b

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Publication Date
Mon Mar 08 2021
Journal Name
Baghdad Science Journal
Evaluation of the one electron expeetation values for different wave functions
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The aim of this work is to evaluate the onc-electron expectation values < r > from the radial electronic density funetion D(r) for different wave ?'unctions for the 2s state of Li atom. The wave functions used were published in 1963,174? and 1993 , respectavily. Using " " ' wave function as a Slater determinant has used the positioning technique for the analysis open shell system of Li (Is2 2s) State.

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Publication Date
Sat Dec 13 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of the relationship between curve of Spee and dentofacial morphology in different skeletal patterns
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Background: Curve of Spee (CS) is an anteroposterior anatomical curve established by the occlusal alignment of the teeth viewed in the sagittal plane. This occlusal curvature has clinical importance in orthodontics and other fields of dentistry. This study aimed to evaluate the relationship between the CS and dentofacial morphology of different skeletal patterns in both genders. Materials and Methods: Eighty six Iraqi Arab subjects (44females,42 males ) their age ranged from 17 -30 years, classified into: Skeletal I with normal occlusion(15 females and 15 males), skeletal II with CI II div 1 malocclusion (15 females and 15 males) and skeletal III with CI III malocclusion (14 females and 12 males). Forty one variables measured us

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Publication Date
Fri Jul 01 2016
Journal Name
Al–bahith Al–a'alami
Manufacturing the Functions and Responsibilities of the Press Photo: The Photo of the Child Elian as a Model
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The theory of the psychologist’s Piaget states that man passes through four stages; other says that mankind passes through five. At each stage, human learn new characteristics, values, skills, and cultures from different environment that differ from one society to another. Therefore, the cultures of societies vary according to the diversity of the environments. These environments also vary depending on the circumstances surrounding them, e.g., in war environment, the individual learns what he does not learn from living in safe environment. As the environment changes, the communicative message also changes. This message is subject to person, groups, organizations and parties and directed to a diverse audience in its orientations and bel

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Publication Date
Sat Dec 13 2025
Journal Name
Journal Of Physical Education
The Effect of Sock Exercises On Bench Press Achievement Of National League Weightlifters With Special Needs
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