scholarly journals Adaptation Measurement of CAD/CAM Dental Crowns with X-Ray Micro-CT: Metrological Chain Standardization and 3D Gap Size Distribution

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
L. Tapie ◽  
N. Chiche ◽  
P. Boitelle ◽  
P. Morenton ◽  
J.-P. Attal ◽  
...  
Keyword(s):  
Size Distribution ◽  
Computer Aided Design ◽  
Manufacturing Systems ◽  
Gap Size ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Final Assembly ◽  
Gap Measurement ◽  
Cad Cam

Computer-Aided Design and Manufacturing systems are increasingly used to produce dental prostheses, but the parts produced suffer from a lack of evaluation, especially concerning the internal gap of the final assembly, that is, the space between the prepared tooth and the prosthesis. X-ray micro-Computed Tomography (micro-CT) is a noninvasive imaging technique enabling the internal inspection of the assembly. It has proved to be an efficient tool for measuring the gap. In this study, a critical review of the protocols using micro-CT to quantify the gap is proposed as an introduction to a new protocol aimed at minimizing errors and enabling comparison between CAD/CAM systems. To compare different systems, a standardized protocol is proposed including two reference geometries. Micro-CT is used to acquire the reference geometries. A new 3D method is then proposed and a new indicator is defined (Gap Size Distribution (GSD)). In addition, the usual 2D measurements are described and discussed. The 3D gap measurement method proposed can be used in clinical case geometries and has the considerable advantage of minimizing the data processing steps before performing the measurements.

scholarly journals Characterisation of the Filler Fraction in CAD/CAM Resin-Based Composites

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1986
Author(s):  
Andreas Koenig ◽  
Julius Schmidtke ◽  
Leonie Schmohl ◽  
Sibylle Schneider-Feyrer ◽  
Martin Rosentritt ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Point Of View ◽  
Specific Information ◽  
Dental Resin ◽  
X Ray ◽  
Computer Aided ◽  
Cad Cam ◽  
Filler Fraction ◽  
The Individual ◽  
Aided Design

The performance of dental resin-based composites (RBCs) heavily depends on the characteristic properties of the individual filler fraction. As specific information regarding the properties of the filler fraction is often missing, the current study aims to characterize the filler fractions of several contemporary computer-aided design/computer-aided manufacturing (CAD/CAM) RBCs from a material science point of view. The filler fractions of seven commercially available CAD/CAM RBCs featuring different translucency variants were analysed using Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), Micro-X-ray Computed Tomography (µXCT), Thermogravimetric Analysis (TG) and X-ray Diffractometry (XRD). All CAD/CAM RBCs investigated included midifill hybrid type filler fractions, and the size of the individual particles was clearly larger than the individual specifications of the manufacturer. The fillers in Shofu Block HC featured a sphericity of ≈0.8, while it was <0.7 in all other RBCs. All RBCs featured only X-ray amorphous phases. However, in Lava Ultimate, zircon crystals with low crystallinity were detected. In some CAD/CAM RBCs, inhomogeneities (X-ray opaque fillers or pores) with a size <80 µm were identified, but the effects were minor in relation to the total volume (<0.01 vol.%). The characteristic parameters of the filler fraction in RBCs are essential for the interpretation of the individual material’s mechanical and optical properties.

Implementation of Rapid Manufacturing Systems in the Jewellery Industry in Brazil

2011 ◽  
pp. 119-138
Author(s):  
Juan Carlos Campos Rubio ◽  
Eduardo Romeiro Filho
Keyword(s):  
Computer Aided Design ◽  
Manufacturing Systems ◽  
Medium Size ◽  
Manufacturing Processes ◽  
Computer Aided ◽  
Design And Manufacturing ◽  
Cad Cam ◽  
High Production ◽  
Rapid Prototyping And Manufacturing ◽  
Aided Design

This chapter presents the rapid prototyping and manufacturing concepts applied as means to reducing time between jewellery designs and manufacturing process. Different processes on jewellery modelling production are presented. Nowadays, the use of technologies as CAD/CAM - Computer Aided Design and Manufacturing in high production companies are very disseminated. However, the implementation of these resources at the design and manufacturing processes of jewels and fashion accessories, in small and medium size businesses, is still insipient. As reference, is presented the situation observed in small and medium companies located in Minas Gerais, Brazil.

scholarly journals Endogenous Production of n-3 Polyunsaturated Fatty Acids Promotes Fracture Healing in Mice

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Yuhui Chen ◽  
He Cao ◽  
Dawei Sun ◽  
Changxin Lin ◽  
Liang Wang ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Fracture Healing ◽  
Histological Analysis ◽  
Callus Formation ◽  
Healing Process ◽  
Proximal Femoral Fracture ◽  
Fracture Repair ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray

Bone fracture is a global healthcare issue for high rates of delayed healing and nonunions. Although n-3 polyunsaturated fatty acid (PUFA) is considered as a beneficial factor for bone metabolism, only few studies till date focused on the effects of n-3 PUFAs on fracture healing. In this study, we investigated the effect of endogenous n-3 PUFAs on fracture healing by measuring femur fracture repair in bothfat-1transgenic mice and WT mice. Proximal femoral fracture model was established infat-1transgenic mice and WT mice, respectively, and then the fracture was analyzed by using X-ray, micro-computed tomography (micro-CT), and histological assessment at 7, 14, 21, 28, and 35 days after fixation. The results showed that compared with WT mice,fat-1mice exhibited acceleration in fracture healing through radiographic and histological analysis (18–21 days versus 21–28 days postfracture). Meanwhile, X-ray and micro-CT analysis that showed better remodeling callus formation were in thefat-1group compared to WT group. Furthermore, histological analysis revealed that endogenous n-3 PUFAs promoted local endochondral ossification and accelerated the remodeling of calcified calluses after fracture. In conclusion, the present study indicated that endogenously produced n-3 PUFAs promote fracture healing process and accelerate bone remodeling in mice, and supplementation of n-3 PUFAs was positively associated with fracture healing.

scholarly journals Investigating the Evolution of Fractures in Clay–based Ceramics During Repeated Freeze-Thawing Cycles Using Micro X-Ray Computed Tomography and Image Analysis

2020 ◽  
Author(s):  
Carlo Porfido ◽  
Roberto Rizzo ◽  
David Healy ◽  
Matteo Spagnuolo ◽  
Roberto Terzano ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Methodological Approach ◽  
Fracture Initiation ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Freeze Thaw ◽  
Fracture Length ◽  
Grain Distribution ◽  
Fracture Damage

<div><div><div><p>This work presents a study on the fracturing behaviour of a quartz tempered clay-based ceramic subjected to damage in freeze-thaw cycles. X-ray micro-computed tomography (micro-CT) provided high-resolution imaging of the ceramic before and during the freeze-thaw treatment, allowing to analyse a fully water-saturated sample using a special thermal stage designed to keep the sample frozen during analyses. Micro-CT 3D renderings showed the internal features of the specimen (i.e., quartz grain distribution), the increment of fracture count and size, and the detachment of ceramic and/or temper fragments from the edges of the sample over the cycles. Selected 2D micrographs, before and after freeze-thawing treatment, were analysed using the MATLAB toolbox FracPaQ. This software provided detailed data on fracture length, intensity, density, orientation and connectivity, and enabled to interpret the process of fracture initiation and propagation inside the material. These results showed that the temper plays a crucial role in ceramic fracturing behaviour under freeze- thawing conditions, as damage propagation is influenced by quartz grain distribution and orientation within the material. The study described in this work, not only offers new insights into the fracture dynamics of freeze-thawed clay-based ceramics, but also presents a new methodological approach to quantitatively measure fracture damage in porous materials.</p></div></div></div>

scholarly journals Generalized Pulp Stones of Primary Dentition in a Patient with Molar-Incisor Malformation : A Case Report

2020 ◽  
Vol 47 (3) ◽  
pp. 337-343
Author(s):  
Dongyun Lee ◽  
Jisun Shin
Keyword(s):  
Case Report ◽  
Primary Dentition ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Second Molar ◽  
New Type ◽  
Mandibular First Molar ◽  
Pulp Stones ◽  
Scanning Electron

Molar-incisor malformation (MIM) is a new type of root anomaly reported recently. The characteristics of MIM are dysplastic root formations, constriction of pulp chambers and presence of calcified matrices at the level of cementoenamel junction in permanent first molars and primary second molars. In some cases, permanent maxillary incisors are also affected.The permanent first molars of the patient in this case report were affected with MIM. Generalized pulp stones were observed in overall primary dentition. Micro-computed tomography (micro-CT) imaging and scanning electron microscope-energy dispersive X-ray spectrometer analysis were performed on the extracted mandibular first molar and maxillary primary second molar of the patient. Micro-CT images revealed the discontinuity of enamel directly connected to an accessory canal of the root.

scholarly journals Topographical evaluation of laser generated surfaces using statistical analysis of surface-normal vector distributions

2021 ◽  
Vol 1135 (1) ◽  
pp. 012023
Author(s):  
Rickard Olsson ◽  
John Powell ◽  
Jan Frostevarg ◽  
Alexander F.H. Kaplan
Keyword(s):  
Surface Roughness ◽  
Measurement Techniques ◽  
Considerable Effect ◽  
Normal Vector ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
New Techniques ◽  
X Ray ◽  
Independent Analysis ◽  
Surface Profiles

Abstract Surfaces generated by Additive Manufacturing or laser texturing can involve the solidification of droplets of liquid, which can give rise to overhanging features on the solidified surface. Overhanging features add a layer of complexity to the surface topography and are undetectable by standard surface roughness measurement techniques such as profilometry. Such features are important because they can have a considerable effect on surface properties such as wettability. New techniques and algorithms are therefore required to analyse and quantify convoluted surfaces with overhanging (re-entrant) features. Earlier work by the authors introduced the concept of using X-ray micro-computed tomography (Micro-CT) to identify the directions of vectors normal to the surface at any point and thus indicate the presence or absence of overhanging features. This paper divides overhanging features into two types; simple and compound, and introduces new, size independent, analysis techniques which measure what proportion of each type is on the surface. Another extension of the analysis is the comparison of surface profiles taken in different directions in order to identify any surface roughness anisotropies.

scholarly journals A Review of Current Challenges and Case Study toward Optimizing Micro-Computed X-Ray Tomography of Carbon Fabric Composites

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3606
Author(s):  
Armin Rashidi ◽  
Tina Olfatbakhsh ◽  
Bryn Crawford ◽  
Abbas S. Milani
Keyword(s):  
Computed Tomography ◽  
Woven Fabric ◽  
Fiber Reinforced Polymers ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Fabric Composites ◽  
Low X ◽  
Composite Fabrics

X-ray computed tomography provides qualitative and quantitative structural and compositional information for a broad range of materials. Yet, its contribution to the field of advanced composites such as carbon fiber reinforced polymers is still limited by factors such as low imaging contrast, due to scarce X-ray attenuation features. This article, through a review of the state of the art, followed by an example case study on Micro-computed tomography (CT) analysis of low X-ray absorptive dry and prepreg carbon woven fabric composites, aims to highlight and address some challenges as well as best practices on performing scans that can capture key features of the material. In the case study, utilizing an Xradia Micro-CT-400, important aspects such as obtaining sufficient contrast, an examination of thin samples, sample size/resolution issues, and image-based modeling are discussed. The outcome of an optimized workflow in Micro-CT of composite fabrics can assist in further research efforts such as the generation of surface or volume meshes for the numerical modeling of underlying deformation mechanisms during their manufacturing processes.

Evaluation of Metal Lattice Structures With X-Ray Micro-Computed Tomography: Dimensional Accuracy and Manufacturability

2020 ◽  
Author(s):  
Tuomas Puttonen
Keyword(s):  
Computed Tomography ◽  
Computer Aided Design ◽  
Dimensional Accuracy ◽  
Lattice Structures ◽  
Micro Computed Tomography ◽  
Original Design ◽  
Voxel Size ◽  
X Ray ◽  
Lattice Design ◽  
Metal Lattice

Abstract Additive manufacturing enables product designers to incorporate complexity onto their designs on multiple size scales. Computer-aided design methods, such as topology optimization and lattice design, have emerged as software tools for applications where part consolidation and weight reduction are desired. Still, a more delicate control of hierarchical complexity and submillimeter-sized features would unlock a widely unexplored frontier of new design possibilities. However, the complexity of a design can respectively affect the manufacturing process. In powder bed fusion, the diameter, power and speed of the laser spot and the resulting size of the melt pool define the attainable feature resolution and accuracy in comparison with the original design intent. X-ray computed tomography can be a useful tool in validation and provide a detailed, volumetric representation of a part with internal features. This paper examines the design accuracy of 316L metal lattice structures and density of solid cubes with industrial X-ray micro-computed tomography. Accessible tools with open source software are presented for CT data analysis. The nominal values are compared against the as-built and CT scanned samples for surface area, volume, and dimensional accuracy. A CT voxel size of 30–40 μm allows to identify printability issues and general trends in the part density in comparison to the geometry changes. However, a finer voxel size in the submicron range would be required to properly detect and localize internal porosity and evaluate surface topography.

scholarly journals Micro-CT study of Middle Ordovician Spumellaria (radiolarians) from western Newfoundland, Canada

2020 ◽  
Vol 94 (3) ◽  
pp. 417-435 ◽  
Author(s):  
Sarah Kachovich ◽  
Jonathan C. Aitchison
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Detailed Examination ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Lower Paleozoic ◽  
X Ray ◽  
Middle Ordovician ◽  
Radiolarian Assemblage ◽  
Taxonomic Groups

AbstractA new, previously undescribed Middle Ordovician (middle Darriwilian: Dw2) radiolarian assemblage has been recovered from the Table Cove Formation at Piccadilly Quarry, western Newfoundland. Constituents of the fauna described herein are both distinctive and exceptionally well preserved. Three-dimensional X-ray micro-computed tomography (μ-CT) is used to make a detailed examination of four key spumellarian specimens. This technology enables visualization of hitherto ambiguous details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has impeded resolution of higher taxonomic rankings.

Internal Structure of the Sheared Textile Composite Reinforcement: Analysis Using X-Ray Tomography

2015 ◽  
Vol 651-653 ◽  
pp. 325-330 ◽  
Author(s):  
Marcin Barburski ◽  
Ilya Straumit ◽  
Stepan V. Lomov
Keyword(s):  
Image Processing ◽  
Internal Structure ◽  
Image Data ◽  
Woven Fabric ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Textile Composite ◽  
Fibre Direction ◽  
X Ray ◽  
Geometrical Properties

X-ray micro computed tomography (Micro-CT) is a non-destructive technique that can provide information on the internal structure of materials. The purpose of micro-CT is to assess the presence of defects as well as characterizing internal structures and potential damage present in the produced part. Simple shear is an interesting deformation mechanism for woven fabric draping. The internal structure change of the carbon fibre twill fabric after shear deformation is chosen as a subject of this paper. Parameters of the mesoscopic internal structure of the woven fabric like cross section, shape, area, and middle line coordinates can be obtained from micro-CT images through image processing procedures. Details of the image data processing for sheared fabric cross sections are discussed. This paper illustrates the possibilities of micro-focus computer tomography in materials research, namely for defining geometrical properties of textile. Image processing is also used for the recognition of fibre direction in the yarns. Described methodology can be applied for determining structure of a fabric, and the results can be used for further micromechanical modelling. Identification of the fibres orientation is important for estimation of the mechanical properties of composites and can be achieved with image processing techniques.

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