Context: The ability of implant dentistry to be a successful alternative for edentulous patients has increased in the last decade. Clinical features such as osseointegration and stability, in addition to the endurance of the integration urged the researchers towards a better understanding of the design parameters that control long term success of the implants. It is therefore necessary to quantify the effect of changing implant design parameters on interface stress distribution within the maxilla bone. Methods and Materials: A 3D-finite element study was conducted to investigate the effect of changing implant shape parameters (implant body design and implant thread depth) on stress distribution while insertion of the implant in two different regions of maxilla bone (anterior (type III bone) and posterior (type IV bone)). A 3D-CAD geometry of implant-maxilla bone was created through importing digitally visualized CT skull images of a human adult, and then converted into a workable solid body through using a collection of engineering software. Tapered and cylindrical implant models with three different implant V-shaped thread depths (0.25 mm, 0.35 mm, 0.45 mm) were threaded into maxilla bone to investigate the design parameters effect on the final stress status. The proposed implant was of commercial dimensions of 10 mm length and 4 mm in diameter. A vertical static load of 250N was directly applied to the center of the suprastructure of the implant for each model. Results: Evaluations were performed for stress distribution patterns and maximum equivalent Von Mises (EQV) stresses for implants in two regions of maxilla bone under 250N vertical static loading. The obtained results throughout this work showed that, for all models, the highest stresses were located at the crestal cortical bone around the implant neck. The von-Mises stress distribution patterns at different models were similar and higher peak von-Mises stresses of cortical bone were seen in tapered implant body compared to cylinder body in all models. Conclusions: Within the restrictions of the current model, the results obtained can be applied clinically to select properly both implant thread depth and body shape design for a foreseeable success of implant therapy.
For the design of a deep foundation, piles are presumed to transfer the axial and lateral loads into the ground. However, the effects of the combined loads are generally ignored in engineering practice since there are uncertainties to the precise definition of soil–pile interactions. Hence, for technical discussions of the soil–pile interactions due to dynamic loads, a three-dimensional finite element model was developed to evaluate the soil pile performance based on the 1 g shaking table test. The static loads consisted of 50% of the allowable vertical pile capacity and 50% of the allowable lateral pile capacity. The dynamic loads were taken from the recorded data of the Kobe e
Manipulation is a discursive concept which plays a key role in political discourse by which politicians can impose some impact on their recipients through using linguistic features, most prominent of which are personal pronouns (Van Dijk, 1995). The aim of this study is to investigate how politicians utilize the personal pronouns, namely; We and I and their possessive forms as a tool of manipulating the audience's mind based on Van Dijk's "ideological square" which shows positive-self representation and negative-other representation (Van Dijk,1998:p.69). To this end, American President Donald Trump's 2020 State of the Union speech was chosen to be the data of analysis. Only (8)
... Show MoreAbstract Background: Articular cartilage lesions in the knee joint are frequently seen,its treatment represents a challenge for orthopedic surgeons especially in young age patients and if left untreated,then they can progress to advanced osteoarthritis that may affect the functional status of the patients.Many treatment modalities had developed for these lesions, in the current study arthroscopic micro fracture plus intra articular whole bone marrow(WBM) injection was used as modality of treating these lesions. Objectives: to assess the effectiveness of arthroscopic micro fracture plus WBM intra articular injection as a treatment modality for knee articular cartilage lesions. Patients and Methods : a prospective experimental study was perf
... Show MoreBackground: The long term survival of dental implants is evaluated by the amount of crestal bone loss around the implants. Some initial loss of bone around dental implants is generally expected. There is reason to believe that reflecting a mucoperiosteal flap promotes crestal bone loss in the initial phase after an implant has been inserted. The surgical placement of a dental implant fixture is constantly changing and in recent years, there has been some interest in developing techniques that minimize the invasive nature of the procedure, with flapless implant surgery being advocated. The purpose of this study was to compare the radiographic level of the peri- implant bone after implant placement between traditional flapped surgery and f
... Show MoreThis paper offers a postcolonial analysis of Sudanese author Tayeb Salih's novel Season of Migration to the North (1966), emphasizing the interplay between indigenous and colonial narratives. The analysis centers on the protagonist, Mustafa Sa'eed, who embodies its essence. The character of Mustafa Saeed represents the intricate interplay between colonial and indigenous elements. This research employs Edward Said's postcolonial concept, Contrapuntal Reading (1993), which underscores the interconnection of the histories of colonizers and the colonized through the portrayal of Mustafa Saeed's character, focusing on the mechanisms of colonial power, such as cultural hegemony, identity manipulation, and the resistance of the colonized.
... Show MoreThe settlement evaluation for the jet grouted columns (JGC) in soft soils is a problematic matter, because it is influenced by the number of aspects such as soil type, effect mixture between soil and grouting materials, nozzle energy, jet grouting, water flow rate, rotation and lifting speed. Most methods of design the jet-grouting column based on experience. In this study, a prototype single and group jet grouting models (single, 1*2, and 2*2) with the total length and diameter were (2000 and 150 mm) respectively and clear spacing (3D) has been constructed in soft clay and subjected to vertical axial loads. Furthermore, different theoretical methods have been used for the estimation
ABSTRACT Purpose: the aim of this in vitro study was to compare the marginal gap and internal fitness between single crowns and the crowns within three-unit bridges of zirconium fabricated by CAD-CAM system. Materials and methods: A standard model from ivoclar company was used as a pattern to simulate three-units bridge (upper first molar and upper first premolar) as abutments used to fabricate stone models, eight single crowns for premolar and eight of three units bridges. Crowns and bridges fabricated by CAD-CAM system were cemented on their respective stone models then sectioned at the mid-point buccolingaully and misiodistaly and examined under stereomicroscope. Result: the marginal gap in premolar crowns and premolar within bridge we
... Show MoreAn experimental study was performed to estimate the forced convection heat transfer performance and the pressure drop of a single layer graphene (GNPs) based DI-water nanofluid in a circular tube under a laminar flow and a uniform heat flux boundary conditions. The viscosity and thermal conductivity of nanofluid at weight concentrations of (0.1 to 1 wt%) were measured. The effects of the velocity of flow, heat flux and nanoparticle weight concentrations on the enhancement of the heat transfer are examined. The Nusselt number of the GNPs nanofluid was enhanced as the heat flux and the velocity of flow rate increased, and the maximum Nusselt number ratio (Nu nanofluid/ Nu base fluid) and thermal performance factor
... Show MoreThe current work aims to evaluate the association between genetic mutations in thymidylate synthetase (
Background: The restoration of bone continuity and bone union are complex processes, and their success is determined by the effectiveness of osteosynthesis. The use of plants for healing purposes predates human history and forms the source of current modern medicine The aim of this study: It was histological evaluation of effect of topical application of flavonoid on healing of induced bone defect in rabbit tibia. Material and method: Twenty-four Adult New Zealand rabbits used in this study, they were divided into four groups for the healing periods (3days, 1,2, and 4weeks) Two holes were induced in rabbit tibia one on the left side and has been left to heal normally as control. While, the other hole made on the right side filled with flavo
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