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The number of supporting dental implants is an important criterion for the surgical outcome of dental bridge fixation, which has considerable impact on biomechanical load transfer characteristics. Excessive stress at the bone–implant interface by masticatory loading may result in implant failure. The aim of this study was to evaluate the impact of the number of implants supporting the dental bridge on stress in neighboring tissues around the implants. Results of the study will provide useful information on appropriate surgical techniques for dental bridge fixation. In this study, osseointegrated smooth cylindrical dental implants of same diameter and length were numerically analyzed, using three-dimensional bone–implant models. The effect of the number of supporting implants on biomechanical stability of dental bridge was examined, using two, three and four supporting implants. All materials were assumed to be linearly elastic and isotropic. Masticatory load was applied in coron-apical direction on the external part of dental bridge. Finite Element (FE) analyses were run to solve for von Mises stress. Maximum von Mises stresses were located in the cervical line of cortical bone around dental implants. Peak von Mises stress values decreased with an increase in the number of implants that support the dental bridge. Results of this study demonstrate the importance of using the correct number of supporting implants to for dental bridge fixation.

Posterior composite restorations are difficult to contour and polish due to their occlusal anatomy and opposing occlusion. Our study describes a technique for duplicating occlusal surface anatomy, using different dental materials that are able to copy anatomic details. The aim of the study was to evaluate the efficiency of occlusal matrix technique, by comparing technical ease of different dental materials. The study was conducted on extracted teeth which had intact occlusal surfaces or initial carious lesions at this level. An impression of the occlusal surface was made prior to cavity preparation, with four different dental materials: a flow composite, a dual-cure resin cement, a temporary acrylic resin (powder and liquid) and a temporary crown and bridge two-component material in a Unidose®. When the last layer of composite has been placed, the occlusal matrix was forced into the uncured composite to replicate the original occlusal surface, instead of performing manual curing and shaping as in the standard approach. Time needed for complete finishing the case, the hardness of each occlusal matrix and the final morphology obtained were evaluated. The main benefits of the occlusal matrix technique are the technical ease of use due to its simplicity and its high accuracy in reconstructing occlusal morphology. Although the shortest time needed for occlusal matrix preparation was for the dual-cure resin cement, the best oclusssal matrix was obtained with the temporary acrylic resin (powder and liquid).

Dental restorations are currently produced mainly by conventional dental technology methods. The automation of the manufacturing process can be achieved by the use of CAD/CAM technology. Basic research on the most important aspects of CAD/CAM fixed dental restorations from the viewpoint of production, information technology, and dentistry/dental technology are the subject of a current article. The aim of this article is practical using of computer aided technologies such as 3D scanning and 5-axis machining for designing and fabrication of dental restorations. It further explains the detailed process of acquiring a digital description of tooth’s shape and its subsequent modification. Attention is drawn to a detailed analysis of dental restorations’ design obtained from a digital description of a tooth in Cercon Art software. The last part of this paper concentrates on the fabrication of dental restorations, which took place at CAD/CAM dental centre in Bratislava, Slovakia. The fabrication was accomplished by 5-axis kinematic structure of machine tools.

The 3D printing method for the human tooth is a possible and good solution in the manufacture. However, the shrinkage is the most challenging problem to manufacture the tooth. In this paper, CAE analysis and experimental design are applied to predict the shrinkage of different dentures shape. Then the CAD model of the dentures can be reverse amplified before the sintering process. The product will be close to the patients’ requirements with precise dentures shape. It also avoids the complicated procedure of CNC machining and reduces dentists finishing time. The dental bridge is the main research objective investigated in this paper to verify the CAE simulation developed by the authors.

It is major, simple structure and wide scope of use on Gravity abutment of plain concrete, But most of the wall of abutment appears irregular cracks, affect the economy and durability of the abutment and bridge seriously. The paper is based on a bridge of Jiang Xi Rui Xun high-speed engineering, analysis the crack mechanism of abutment by using large-scale finite element software ANSYS to establish reinforcement simulation model of top and bottom ring beam. The stress and vertical deflection of the abutment are meet the requirements, it is meaningful for gravity abutment of plain concrete Strengthening in the future.

A dental bridge, designed in STL format on a Dental Scanner software, was covered with the porcelain layer in 3-matic Design ©Materialise NV. FEA simulations were made in ANSYS ® Workbench TM ©SAS, Inc. Firstly, was performed the thermal analysis with the Transient Thermal module, and secondly, the structural static analysis with the Static Structural module. The applied masticatory force was of 300 N, and the studied temperatures were 36°C as reference and, as extremes, 0° and 50°C. The purpose was to determine mechanical effects in the bridge structure for a specific design of the dental bridge geometry in order to optimize its design.

Replace lost teeth by artificial prosthetic has been a preoccupation since the dawn of human time. The aim of our work is to study mechanical behavior of the interaction distance between two dental implants, in order to serve as support for a crown, a bridge element or an attachment of the prosthesis.Our purpose is to make a comparative study of five models that is different only by the interaction distance between 0.5 mm and 2 mm spacing two implants, to clarify the mechanical behavior of this interaction distance. The used materials are the biomaterials which are intended to be in contact with biological systems. Modeling of dental implant and the various components is done using Solidworks.We studied the static mechanical behavior of the implant using numerical methods.

Fabricated hollow slab bridge is commonly used in China. It is indicated that the hinged joints between hollow slabs are easily damaged. Especially under the erosion of chloride salt, the destruction process of hinged joints will be greatly exacerbated. In this paper, deicing salt environment was simulated in the lab to corrode the commonly used hinged joints. According to static load test results, hollow slab coordinated working coefficient is explored and the regression calculation formula was established. Then, the time-varying function of the rate of hinged joint steel corrosion was introduced to the regression model. Finally, the constantly evaluating of the hinged joint durability performance of common used deep, middle and low hinged joint forms were also carried out.

Bridge tooling has been developed for fabricating the temporary mould inserts of aspheric lenses using silicone rubber materials. Prototype material for aspheric lenses is not recommended as quartz due to the low success rate in the fabrication process. This technology provides a fast, low cost and highly successful rate of fabricating the epoxy-based composite mould inserts of plastic aspheric optical lenses.

The treatment of soft soil foundation is a common but hot and difficult problem in the construction projects. Based on the reinforced treatment of abutment foundation in Fuyan Bridge and the hypothesized different treatment measures, settlement deformation of abutment foundation was calculated and analyzed by means of software ANSYS; variations of synthetic modulus for foundation soil and curves of settlement deformation of abutment foundation were obtained, which offers references to the design and construction of such projects.

In order to analyze the impact of anchor length, ends anchorage measures, strength of concrete, shear-span ratio, reinforcement ratio and the amount of carbon fiber plate on the bearing capacity of strengthened bridge structures with carbon fiber plate, 11 pieces of rectangle beams are fabricated for flexural experimental study. The experimental results show that the ultimate bearing capacity of the specimens increase different degree as different strengthened schemes: the bearing capacity of rectangle beams with plate end anchorage has increased remarkably; The beams have greater bearing capacity with more anchorage length in contrast to those without any anchorage measure; The ultimate bearing capacity enhanced more prominent for those specimens with low shear-span ratio and low reinforcement ratio.

According to the BS7448 fracture toughness test standard and DNV-OS-C401,this dissertation conducted a CTOD(crack tip opening displacement) fatigue crack precast test with the used steel Q370qE in bridge.Respectively tested different thickness mather materials’condition of fatigue crack,and analysis the test’s results,thus obtained the related conclusions.

Aimed at the problems such as welding stress concentration and especially irregular distribution of welding residual stress for anchorage area in cable-stayed bridges, three full-scale beam-anchor-plate connection models of Chongqing Jiangjin Guanyinyan Yangtse Rive bridge were made and the tests were performed. The purposes of the tests and study were to investigate the distribution of welding residual stress in anchorage area and moreover to find a way to reduce and eliminate the welding residual tensile stresses. For this reason ultrasonic impact was imposed on the main welds of the three models. The result of the experiment showed that there were quite considerable welding residual stresses in the anchorage area. It also displayed that the ultrasonic impact was able to effectively decrease and even release the welding residual tensile stress. The ultrasonic impact was able to not only improve the adverse state of the welds stress but also make the distribution of the welds stress smoother. The ultrasonic impact is an effective and feasible method to decrease and eliminate welding residual stress and thereby improve the fatigue strength of welds for the steel bridge.

Gravity abutment widely uses for substructure part of the bridge structure. For many reasons, there are many damages take place in the parts of abutment. The objective of this study is to evaluate the strengthening effects on the performance of highly structure of Gravity abutment. The results of damage inspection show that these damages are very serious in the direction of height and width of the abutment structure. Therefore, there is need to strengthen the abutment structure to improve the carrying capacity. There are two experimental models. The first model uses one ring of carbon fiber sheet and the second uses two rings of carbon fiber sheet .The results of experimental show that there are good effects when using carbon fiber sheet strengthening method.

Hollow glass fiber with full of repair agent is embedded in concrete to repair components, and one - third point loading experiment is carried out to test the mechanical properties of it. Based on the strength analysis of specimens before and after self – healing, the self – healing effect of concrete is evaluated. By simulating the closed heal agent flowing and penetrating into the concrete crack surface under the capillary tension, the influence of crack width to the healing effect is analyzed.

The theoretical models and finite element models of implant-supported fixed partial dentures and surrounding osseous tissues were founded. It was studied of the influence of connector sectional area on implant-supported fixed partial dentures and surrounding osseous tissues. The results indicate that increasing the connector sectional areas to some extent has positive effect on fixed bridge itself. But the maximum stresses in some regions of surrounding osseous tissues increase as the connector sectional areas increase, the change extent is smaller comparatively. The study provides biomechanics evidence for the optimum design of implant-supported fixed partial dentures.

The aim of this work was to establish a route to produce pre-sintered blocks of Y-TZP (yttria stabilized tetragonal zirconia polycrystal) suitable to be machined in a commercial CADCAM system, used to manufacture crowns and bridge frameworks for dental applications. Two commercial Y-TZP powders were investigated. The powders were pressed with different compaction pressures (40 to 500 MPa) and pre-sintered at temperature ranging from 900 to 1100°C. Vickers hardness, biaxial flexural strength, and linear shrinkage could be correlated to the relative density of pre-sintered samples. Using an empirical equation, pre-sintered blocks with a pre-defined density could be prepared. The blocks withstood the machining in a CAD-CAM system, and the machined and sintered crowns presented good adaptation.

In recent years, the replacement repair welding, through which damaged bridges are repaired by replacing of the damaged sections with new steel plates through cutting and welding under in-service conditions, has been highlighted for its brilliant features i.e. it can be achieved without incurring traffic dislocation. However, the validity of the repair method is not fully verified because of its lack of safety and reliability. Moreover, repair method by welding inevitably involves cutting and welding process, and the weldability of the replacement repair welded joints has not yet been clarified. In this paper, the weldability of the replacement-repair-welded joints was investigated in order to improve reliability in the repair welded joints of the aged steel bridge. A Steel plate was extracted from the steel bridge after the period of prolonged service, and was welded with a new plate, using replacement repair welding technique, in order to construct a specimen. Flux Cored Arc Welding (FCAW) process was used to fabricate the double "V" butt joints. Welded joints were characterized on the basis of chemical composition analysis, hardness test and micro-structural analysis.