scholarly journals SURFACE MODELING FOR CAD/CAM BASED ON NURBS

2011 ◽  
Vol 14 (4) ◽  
pp. 44-52
Author(s):  
Hien Tat Le ◽  
Hung Xuan Nguyen ◽  
Cang Trong Vo
Keyword(s):  
Computer Aided Design ◽  
Geometric Modeling ◽  
Surface Modeling ◽  
Digital Design ◽  
Nurbs Surface ◽  
Computer Aided ◽  
Modeling Techniques ◽  
Cad Cam ◽  
Numerical Performance ◽  
Aided Design

In the digital design process, surface modeling is required to be as accurate as possible for the effective support of production as well as for numerical performance analysis. This article reviews the geometric modeling techniques, based on non-uniform rational B-spline (NURBS). The NURBS surface can be readily translated into many CAD/CAM packages (Computer Aided Design/Computer Aided Manufacturing), which is more convenient for visualization performance and finite element methods.

Structural Analysis of Product and Computer-Aided Assembly Planning in AssemBL Software Package

2018 ◽  
pp. 11-33
Author(s):  
A. N. Bozhko
Keyword(s):  
Computer Aided Design ◽  
State Of The Art ◽  
Graph Model ◽  
Design System ◽  
Assembly Planning ◽  
Complex Products ◽  
Assembly Sequences ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

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.

scholarly journals Evaluation of the Feasibility of NaCaPO4-Blended Zirconia as a New CAD/CAM Material for Dental Restoration

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3819
Author(s):  
Ting-Hsun Lan ◽  
Yu-Feng Chen ◽  
Yen-Yun Wang ◽  
Mitch M. C. Chou
Keyword(s):  
Computer Aided Design ◽  
Optical Microscope ◽  
Dental Restoration ◽  
Numerical Control ◽  
Test Results ◽  
Cnc Machine ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design ◽  
Better Than

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.

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.

scholarly journals Influence of Sequential CAD/CAM Milling on the Fitting Accuracy of Titanium Three-Unit Fixed Dental Prostheses

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1401
Author(s):  
Doo-Bin Song ◽  
Man-So Han ◽  
Si-Chul Kim ◽  
Junyong Ahn ◽  
Yong-Woon Im ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Computer Aided Design ◽  
Dental Prostheses ◽  
Computer Aided ◽  
Cad Cam ◽  
Fixed Dental Prostheses ◽  
Gap Data ◽  
Aided Design ◽  
Fitting Accuracy

This study investigated the fitting accuracy of titanium alloy fixed dental prostheses (FDP) after sequential CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) fabrication. A three-unit FDP model connecting mandibular second premolars and molars was prepared and scanned to fabricate titanium FDPs by CAD/CAM milling. A total of six FDPs were sequentially milled in one titanium alloy disk using a new set of burs every time (n = 4). The fitting accuracy of FDPs was mesiodistally evaluated by a silicone replica technique and the measurement was triplicated at four different locations: MO (marginal opening), MG (marginal gap), AG (axial gap), and OG (occlusal gap). Data were statistically analyzed using ANOVA and Tukey’s HSD test. The fitting accuracy of PMMA (polymethyl methacrylate) FDPs milled using the worn or new bur were evaluated by the same procedure (n = 6). The mean dimensions of titanium FDP for all measuring positions, except for AG, were significantly increased from the third milling. However, no difference was noted between the first FDP and the second FDP milled with the same set of burs. Severe edge chippings were observed in all milling burs. Detrimental effects of the worn burs on the fitting accuracy were demonstrated in the CAD/CAM-milled PMMA FDP. The results recommend proper changing frequency of cutting burs to achieve the quality of fit and predictable outcomes for dental CAD/CAM prostheses.

Computer Aided Geometric Design of Two-Parameter Freeform Motions

1999 ◽  
Vol 121 (4) ◽  
pp. 502-506 ◽  
Author(s):  
Q. J. Ge ◽  
M. Sirchia
Keyword(s):  
Computer Aided Design ◽  
Control Structure ◽  
Geometric Design ◽  
Computer Aided Geometric Design ◽  
Kinematic Control ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design ◽  
Two Parameter ◽  
And Robotics

This paper brings together the notion of analytically defined two-parameter motion in Theoretical Kinematics and the notion of freeform surfaces in Computer Aided Geometric Design (CAGD) to develop methods for computer aided design of two-parameter freeform motions. In particular, a rational Be´zier representation for two-parameter freeform motions is developed. It has been shown that the trajectory surface of such a motion is a tensor-product rational Be´zier surface and that such a kinematically generated surface has a geometric as well as a kinematic control structure. The results have not only theoretical interest in CAGD and kinematics but also applications in CAD/CAM and Robotics.

scholarly journals Chairside CAD/CAM Materials: Current Trends of Clinical Uses

Biology ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1170
Author(s):  
Giulio Marchesi ◽  
Alvise Camurri Piloni ◽  
Vanessa Nicolin ◽  
Gianluca Turco ◽  
Roberto Di Lenarda
Keyword(s):  
Clinical Outcome ◽  
Computer Aided Design ◽  
Fabrication Process ◽  
Computer Assisted ◽  
Current Trends ◽  
Computer Aided ◽  
Restorative Materials ◽  
Cad Cam ◽  
Aided Design

Restorative materials are experiencing an extensive upgrade thanks to the use of chairside Computer-aided design/computer-assisted manufacturing (CAD/CAM) restorations. Therefore, due to the variety offered in the market, choosing the best material could be puzzling for the practitioner. The clinical outcome of the restoration is influenced mainly by the material and its handling than by the fabrication process (i.e., CAD/CAM). Information on the restorative materials performances can be difficult to gather and compare. The aim of this article is to provide an overview of chairside CAD/CAM materials, their classification, and clinically relevant aspects that enable the reader to select the most appropriate material for predictable success.

scholarly journals Viability of the Digitalization of Dental Laboratory in Bacolod City

2020 ◽  
Vol 3 (2) ◽  
pp. 31-32
Author(s):  
Paul Brian S. Mendez ◽  
Rizalie N.E. Mibato
Keyword(s):  
Computer Aided Design ◽  
Data File ◽  
Dental Restoration ◽  
Design Data ◽  
Dental Patients ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design ◽  
Improved Accuracy ◽  
The City

Dentistry has evolved from its origin to the present day, becoming almost entirely digitized and supervised. The digitalized dental laboratory saves time due to computer-aided design and computer-aided manufacture (CAD/CAM) technology, which will capture and display clients' tooth or teeth and gums on a 3D image on a computer screen sent to the lab.  It enables a dental lab technician to work faster and get the perfect design of the digital dental restoration. The main advantage of digitalization includes faster and improved efficiency on the turn-around time of devices, like crowns and bridges, and improved accuracy of procedures and manufactured gadgets. Digitalization Dental Laboratory (DDL) is the first to offer a digital dental lab in the city of Bacolod. The service allows laboratories to design the prosthesis digitally from in-house CAD software and email the design data provider or download the data file into a proprietary web host or server. The lab will cater to the digital needs of dental patients of the Multi-Specialty Dental Center (a sister company of DDL) and other dental clients.

Effect of In-office Bleaching on Color, Translucency, and Whiteness Variations in CAD-CAM Monolithic Materials

2021 ◽  
Author(s):  
RG Fonseca ◽  
RC Peńa ◽  
R Simóes ◽  
AC Ramos ◽  
LN Dovigo
Keyword(s):  
Optical Properties ◽  
Computer Aided Design ◽  
Calculated Data ◽  
Color Difference ◽  
Deionized Water ◽  
Stain Removal ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design ◽  
The Impact

SUMMARY Little is known about the impact of bleaching on the optical properties of computer-aided design and computer-aided manufactured (CAD-CAM) monolithic materials. The aim of the present study was to evaluate the effect of one session of in-office bleaching on stain removal, staining susceptibility, translucency, and whiteness variations of CADCAM monolithic materials. Disks were fabricated from Lava Ultimate (LU), Vita Enamic (VE), Vita Suprinity (VS), and IPS e.max CAD (IPS). A spectrophotometer was used to register Commission Internationale de l’Eclairage L*a*b* coordinates. For stain removal, 80 specimens from each material were assessed at baseline (R0) and after immersion in deionized water or coffee for 365 days followed or not by bleaching with 40% hydrogen peroxide (R1). For staining susceptibility, 80 specimens from each material were analyzed at baseline (R0’), and after having been bleached or not and immersed in deionized water or coffee (R1’). Both analyses were calculated as the color difference (ΔE00) between R1-R0 and R1’-R0’, respectively. Differences in translucency (ΔTP00) and whiteness (ΔWID) between R1-R0 and R1’-R0’ were also calculated. Data were analyzed by three-way ANOVA and the Games-Howell post hoc test (α=0.05). Clinical significance was based on 50%:50% perceptibility and acceptability thresholds for ΔE00, ΔTP00 and ΔWID, respectively. Surfaces were analyzed by scanning electron microscopy. Coffee increased ΔE00 in LU, VE, and VS, and decreased their translucency and whiteness, whereas the IPS had only its whiteness affected. Bleaching after immersion in coffee decreased ΔE00 in LU and VE, and increased translucency and whiteness of LU, VE, and VS. No effect was observed on IPS. Bleaching before immersion in coffee decreased translucency of LU, but within the acceptable interval, while VE exhibited lower ΔE00, and became more translucent and less dark. Both VS and IPS were not affected. One session of in-office bleaching benefited optical properties of the previously stained LU, VE, and VS, without increasing their susceptibility to staining or adversely providing clinically unacceptable variations in their translucency and whiteness. All variations exhibited by the IPS were below the perceptible threshold.

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