scholarly journals Effect of Endocrown Restorations with Different CAD/CAM Materials: 3D Finite Element and Weibull Analyses

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Laden Gulec ◽  
Nuran Ulusoy

The aim of this study was to evaluate the effects of two endocrown designs and computer aided design/manufacturing (CAD/CAM) materials on stress distribution and failure probability of restorations applied to severely damaged endodontically treated maxillary first premolar tooth (MFP). Two types of designs without and with 3 mm intraradicular extensions, endocrown (E) and modified endocrown (ME), were modeled on a 3D Finite element (FE) model of the MFP. Vitablocks Mark II (VMII), Vita Enamic (VE), and Lava Ultimate (LU) CAD/CAM materials were used for each type of design. von Mises and maximum principle values were evaluated and the Weibull function was incorporated with FE analysis to calculate the long term failure probability. Regarding the stresses that occurred in enamel, for each group of material, ME restoration design transmitted less stress than endocrown. During normal occlusal function, the overall failure probability was minimum for ME with VMII. ME restoration design with VE was the best restorative option for premolar teeth with extensive loss of coronal structure under high occlusal loads. Therefore, ME design could be a favorable treatment option for MFPs with missing palatal cusp. Among the CAD/CAM materials tested, VMII and VE were found to be more tooth-friendly than LU.

2010 ◽  
Vol 22 (04) ◽  
pp. 327-335 ◽  
Author(s):  
Chun-Li Lin ◽  
Che An Pai

This study evaluates the risk of failure for an endodontically treated premolar with mesio-occlosal (MO) preparation and four different computer-aided design/manufacturing (CAD/CAM) ceramic restoration configurations. Four three-dimensional finite element (FE) models designed with CAD/CAM ceramic inlay, endoinlay, endocrown, and classical crown restorations were constructed to perform simulations. The Weibull function was incorporated with an FE analysis to calculate the long-term failure probability relative to different load conditions. The results indicated that the stress values on the enamel, dentin, and luting cement for endocrown restoration were the lowest values relative to the other three restorations. According to the Weibull analysis, overall failure probabilities were found at 100, 100, 1 and 1% for the inlay, endoinlay, endocrown, and classical crown restorations, respectively in the normal biting. The corresponding values for clenching were over 100% for inlay and endoinlay restorations and about 87 and 70% for endocrown and classical crown, respectively. This numerical investigation suggests that endocrown and classical crown restorations for endodontically treated premolars with MO preparation present similar longevity.


2018 ◽  
Vol 90 (4) ◽  
pp. 652-658
Author(s):  
Péter Deák

Purpose The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view. Design/methodology/approach The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model. Findings The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented. Practical implications The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD. Originality/value The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.


2012 ◽  
Vol 157-158 ◽  
pp. 714-718
Author(s):  
Quan Yuan ◽  
Hai Bo Ma ◽  
Cheng Rui Zhang ◽  
Hua Cong ◽  
Xin Ye

This paper constructs four types of bioprosthetic heart valve’s parametric model via computer aided design, a series of accurate parameters of the bioprosthetic heart valve, such as radius of the sutural ring, height of the supporting stent and inclination of the supporting stent are determined. The finite element method is used to analyze the mechanical properties of the bioprosthetic heart valve in which geometric non-linearity and material non-linearity are all taken into account. The finite element analysis results show that the shape of the bioprosthetic has a significant effect on the mechanical performance of the valve. The stress distribution of ellipsoidal valve leaflets is comparatively reasonable. It has lower peak von-Mises, smaller stress concentration area than the other three types of valve leaflets. This work is very helpful to manufacture valvular leaflets with reasonable shapes and to prolong the lifetime of the bioprosthetic heart valve.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Ennio Bramanti ◽  
Gabriele Cervino ◽  
Floriana Lauritano ◽  
Luca Fiorillo ◽  
Cesare D’Amico ◽  
...  

The aim of this paper is to underline the mechanical properties of dental single crown prosthodontics materials in order to differentiate the possibility of using each material for typical clinical condition and masticatory load. Objective of the investigation is to highlight the stress distribution over different common dental crowns by using computer-aided design software and a three-dimensional virtual model. By using engineering systems of analyses like FEM and Von Mises investigations it has been highlighted the strength over simulated lower first premolar crowns made by chrome cobalt alloy, golden alloy, dental resin, and zirconia. The prosthodontics crown models have been created and put on simulated chewing stresses. The three-dimensional models were subjected to axial and oblique forces and both guaranteed expected results over simulated masticatory cycle. Dental resin presented the low value of fracture while high values have been recorded for the metal alloy and zirconia. Clinicians should choose the better prosthetic solution for the teeth they want to restore and replace. Both prosthetic dental crowns offer long-term success if applied following the manufacture guide limitations and suggestions.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Şemsi Alp ◽  
Laden Gulec Alagoz ◽  
Nuran Ulusoy

The aim of this study is to investigate the stress distributions of different restoration options for class II mesio-occluso-distal (MOD) cavities. A class II MOD cavity with proximal box gingival floor 1 mm below cementoenamel junction was designed in a mandibular first molar tooth model. 3D finite-element analysis (FEA) and 3D-CAD modelling were used to examine the occlusal stresses distributed to the remaining buccal enamel (RBE), remaining lingual enamel (RLE), adhesive surfaces, and restorative materials by direct and indirect materials resulting from a 600 N of static occlusal load stimulating foodstuff. von Mises (VM) and maximum principal (Pmax) stresses were evaluated for two CAD/CAM materials and three direct materials. CAD/CAM materials exerted less stress than the direct restorative materials. Significant von Mises and Pmax stress value differences were seen among all restoration models on RBE. Reducing RLE and including it into the cavity would be a more effective option for this model in this scenario. As VM and Pmax stresses of PIHC CAD/CAM material for RBE and dentin were significantly lower than other tested materials, it may be the choice of material for indirect MOD restorations.


2020 ◽  
Vol 19 ◽  
pp. e208910
Author(s):  
Germana De Villa Camargos ◽  
Priscilla Cardoso Lazari-Carvalho ◽  
Marco Aurélio de Carvalho ◽  
Mariane Boaventura Castro ◽  
Naysa Wink Neris ◽  
...  

Aim: This study aimed the description of a protocol to acquire a 3D finite element (FE) model of a human maxillary central incisor tooth restored with ceramic crowns with enhanced geometric detail through an easy-to-use and low-cost concept and validate it through finite element analysis (FEA). Methods: A human maxillary central incisor was digitalized using a Cone Beam Computer Tomography (CBCT) scanner. The resulted tooth CBCT DICOM files were imported into a free medical imaging software (Invesalius) for 3D surface/geometric reconstruction in stereolithographic file format (STL). The STL file was exported to a computer-aided-design (CAD) software (SolidWorks), converted into a 3D solid model and edited to simulate different materials for full crown restorations. The obtained model was exported into a FEA software to evaluate the influence of different core materials (zirconia - Zr, lithium disilicate - Ds or palladium/silver - Ps) on the mechanical behavior of the restorations under a 100 N applied to the palatal surface at 135 degrees to the long axis of the tooth, followed by a load of 25.5 N perpendicular to the incisal edge of the crown. The quantitative and qualitative analysis of maximum principal stress (ceramic veneer) and maximum principal strain (core) were obtained. Results: The Zr model presented lower stress and strain concentration in the ceramic veneer and core than Ds and Ps models. For all models, the stresses were concentrated in the external surface of the veneering ceramic and strains in the internal surface of core, both near to the loading area. Conclusion: The described procedure is a quick, inexpensive and feasible protocol to obtain a highly detailed 3D FE model, and thus could be considered for future 3D FE analysis. The results of numerical simulation confirm that stiffer core materials result in a reduced stress concentration in ceramic veneer.


2013 ◽  
Vol 300-301 ◽  
pp. 1654-1657
Author(s):  
Quan Yuan ◽  
Hai Bo Ma ◽  
Xu Huang

This paper constructs the parametric model of the spherical heart valve via computer aided design, a series of accurate parameters of the bioprosthetic heart valve, such as the radius of the sutural ring, height of the supporting stent and inclination of the supporting stent are determined. The finite element method is used to determine the effect of the suture density on the dynamic properties of the bioprosthetic heart valve. The finite element analysis results show that the suture has a significant effect on the dynamic properties of the leaflets. The peak stress with different suture density is quite different and the stress distribution with higher suture density is more reasonable than that with lower suture density. In addition, the suture density has more effect at the top of the attachment edge than the other parts of the valve leaflets. This work is very helpful to manufacture the bioprosthetic heart valve with long term durability.


Author(s):  
A. N. Bozhko

Computer-aided design of assembly processes (Computer aided assembly planning, CAAP) of complex products is an important and urgent problem of state-of-the-art information technologies. Intensive research on CAAP has been underway since the 1980s. Meanwhile, specialized design systems were created to provide synthesis of assembly plans and product decompositions into assembly units. Such systems as ASPE, RAPID, XAP / 1, FLAPS, Archimedes, PRELEIDES, HAP, etc. can be given, as an example. These experimental developments did not get widespread use in industry, since they are based on the models of products with limited adequacy and require an expert’s active involvement in preparing initial information. The design tools for the state-of-the-art full-featured CAD/CAM systems (Siemens NX, Dassault CATIA and PTC Creo Elements / Pro), which are designed to provide CAAP, mainly take into account the geometric constraints that the design imposes on design solutions. These systems often synthesize technologically incorrect assembly sequences in which known technological heuristics are violated, for example orderliness in accuracy, consistency with the system of dimension chains, etc.An AssemBL software application package has been developed for a structured analysis of products and a synthesis of assembly plans and decompositions. The AssemBL uses a hyper-graph model of a product that correctly describes coherent and sequential assembly operations and processes. In terms of the hyper-graph model, an assembly operation is described as shrinkage of edge, an assembly plan is a sequence of shrinkages that converts a hyper-graph into the point, and a decomposition of product into assembly units is a hyper-graph partition into sub-graphs.The AssemBL solves the problem of minimizing the number of direct checks for geometric solvability when assembling complex products. This task is posed as a plus-sum two-person game of bicoloured brushing of an ordered set. In the paradigm of this model, the brushing operation is to check a certain structured fragment for solvability by collision detection methods. A rational brushing strategy minimizes the number of such checks.The package is integrated into the Siemens NX 10.0 computer-aided design system. This solution allowed us to combine specialized AssemBL tools with a developed toolkit of one of the most powerful and popular integrated CAD/CAM /CAE systems.


Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan

The application of computer-aided design and manufacturing techniques is becoming essential in modern metal-forming technology. Thus process modeling for the determination of deformation mechanics has been a major concern in research . In light of these developments, the finite element method--a technique by which an object is decomposed into pieces and treated as isolated, interacting sections--has steadily assumed increased importance. This volume addresses advances in modern metal-forming technology, computer-aided design and engineering, and the finite element method.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3819
Author(s):  
Ting-Hsun Lan ◽  
Yu-Feng Chen ◽  
Yen-Yun Wang ◽  
Mitch M. C. Chou

The computer-aided design/computer-aided manufacturing (CAD/CAM) fabrication technique has become one of the hottest topics in the dental field. This technology can be applied to fixed partial dentures, removable dentures, and implant prostheses. This study aimed to evaluate the feasibility of NaCaPO4-blended zirconia as a new CAD/CAM material. Eleven different proportional samples of zirconia and NaCaPO4 (xZyN) were prepared and characterized by X-ray diffractometry (XRD) and Vickers microhardness, and the milling property of these new samples was tested via a digital optical microscope. After calcination at 950 °C for 4 h, XRD results showed that the intensity of tetragonal ZrO2 gradually decreased with an increase in the content of NaCaPO4. Furthermore, with the increase in NaCaPO4 content, the sintering became more obvious, which improved the densification of the sintered body and reduced its porosity. Specimens went through milling by a computer numerical control (CNC) machine, and the marginal integrity revealed that being sintered at 1350 °C was better than being sintered at 950 °C. Moreover, 7Z3N showed better marginal fit than that of 6Z4N among thirty-six samples when sintered at 1350 °C (p < 0.05). The milling test results revealed that 7Z3N could be a new CAD/CAM material for dental restoration use in the future.


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