Dimensional Accuracy of Optical Bite Registration in Single and Multiple Unit Restorations

2013 ◽  
Vol 38 (3) ◽  
pp. 309-315 ◽  
Author(s):  
Y Iwaki ◽  
N Wakabayashi ◽  
Y Igarashi
Keyword(s):  
Optical Method ◽  
Computer Aided Design ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Physical Method ◽  
Registration Data ◽  
Measuring Machine ◽  
The Mean ◽  
Rotational Deviation

SUMMARY The dimensional accuracy of optical bite registration in the CEREC system was compared to that of the conventional physical method in vitro using a bite registration material. Maxillary and mandibular full-arch dentate epoxy models mounted on an articulator were used to measure the interarch distance and the angles created by the occlusal planes. The preparations for a single restoration on the maxillary first molar or for multiple restorations on the maxillary posterior quadrant were made on the model. Optical impression and bite registration data were collected to construct virtual models using computer-aided design software. A silicone material was used for the physical method, and the dimensional accuracy was measured by means of the coordinate measuring machine. The discrepancy relative to the baseline before preparation was analyzed in each registration record. For the single restoration, the optical method created a mean discrepancy of 243.2 μm relative to baseline at the prepared tooth, which was insignificantly but slightly lower than the mean discrepancy of 311.1 μm obtained with the physical method. The mean rotational deviation in the horizontal plane was significantly lower for the optical method. For the multiple preparations, the optical method showed significantly larger discrepancy on the right molar and on the left premolar and molar sites. In the frontal view, the optical method created significantly larger rotational deviation than the physical method. The result indicates that the optical bite registration was effective in terms of dimensional accuracy for single posterior restorations.

scholarly journals In Vitro Comparative Evaluation of Different Types of Impression Trays and Impression Materials on the Accuracy of Open Tray Implant Impressions: A Pilot Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Sonam Gupta ◽  
Aparna Ichalangod Narayan ◽  
Dhanasekar Balakrishnan
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Impression Material ◽  
Impression Materials ◽  
Significant Difference ◽  
Different Types ◽  
Measuring Machine ◽  
The Difference

Purpose. For a precise fit of multiple implant framework, having an accurate definitive cast is imperative. The present study evaluated dimensional accuracy of master casts obtained using different impression trays and materials with open tray impression technique.Materials and Methods. A machined aluminum reference model with four parallel implant analogues was fabricated. Forty implant level impressions were made. Eight groups (n=5) were tested using impression materials (polyether and vinylsiloxanether) and four types of impression trays, two being custom (self-cure acrylic and light cure acrylic) and two being stock (plastic and metal). The interimplant distances were measured on master casts using a coordinate measuring machine. The collected data was compared with a standard reference model and was statistically analyzed using two-way ANOVA.Results. Statistically significant difference (p<0.05) was found between the two impression materials. However, the difference seen was small (36 μm) irrespective of the tray type used. No significant difference (p>0.05) was observed between varied stock and custom trays.Conclusions. The polyether impression material proved to be more accurate than vinylsiloxanether impression material. The rigid nonperforated stock trays, both plastic and metal, could be an alternative for custom trays for multi-implant impressions when used with medium viscosity impression materials.

Trueness and Precision of Three Different Scanners for Digitizing a Completely Edentulous Gypsum Model

2021 ◽  
Vol 11 (1) ◽  
pp. 89-95
Author(s):  
Ammar Kayssoun ◽  
A. Nehir Özden
Keyword(s):  
Computed Tomography ◽  
Statistical Significance ◽  
Three Dimensional ◽  
Coordinate Measuring Machine ◽  
Cone Beam ◽  
Intraoral Scanner ◽  
Measuring Machine ◽  
The Mean ◽  
One Way Anova

Purpose: The aim of this in vitro study was to evaluate the precision and trueness of three different scanners to scan a maxillary edentulous model using three-dimensional evaluation software. Materials and Methods: A coordinate measuring machine was used as the reference scanner. Cone beam computed tomography, computed tomography (CT), and an intraoral scanner were used to digitize an edentulous gypsum model. Data were collected and loaded into three-dimensional evaluation software. The scan outputs were superimposed, and the accuracy (trueness and precision) of the scanners were compared. One-way ANOVA was used to compare the accuracy values among all groups (trueness) and to determine differences within groups (precision). Statistical significance was assessed with an independent sample t-test (= 0.05) for each group. Results: The mean precision values ranged from 3.5 to –0.2 m. Analysis of the superimposed scans onto the reference scan for each group revealed no significant differences in trueness and precision (p > 0.05) among all groups. Further, binary comparisons of the datasets of each group revealed no significant differences (p > 0.05) in terms of precision values, except in the CT group wherein significant differences (p ≤ 0.05) were observed for most models. Conclusions: No significant differences were observed in terms of accuracy (precision and trueness) among the three scanners. All scanners were effective in scanning the edentulous gypsum model.

scholarly journals Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Three Dimensions ◽  
Casting Technique ◽  
Dimensional Changes ◽  
Conventional Casting ◽  
Cad Cam ◽  
Milling Method ◽  
Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

Towards Combining Digitization Techniques in the Generation of Reverse Engineering Data Sets

1999 ◽  
Author(s):  
C. J. Rolls ◽  
W. ElMaraghy ◽  
H. ElMaraghy
Keyword(s):  
Reverse Engineering ◽  
Computer Aided Design ◽  
Laser Scanning ◽  
Single Point ◽  
Laser Scanner ◽  
Coordinate Measuring Machine ◽  
Industrial Applications ◽  
Data Sets ◽  
Error Characterization ◽  
Measuring Machine

Abstract Reverse engineering (RE), may be defined as the process of generating computer aided design models (CAD) from existing or prototype parts. The process has been used for many years in industry. It has markedly increased in implementation in the past few years, primarily due to the introduction of rapid part digitization technologies. Current industrial applications include CAD model construction from artisan geometry, such as in automotive body styling, the generation of custom fits to human surfaces, and quality control. This paper summarizes the principles of operation behind many commercially available part digitization technologies, and discusses techniques involved in part digitization using a coordinate measuring machine (CMM) and laser scanner. An overall error characterization of the laser scanning digitization process is presented for a particular scanner. This is followed by a discussion of the merits and considerations involved in generating combined data sets with characteristics indicative of the design intent of specific part features. Issues in facilitating the assembly, or registration, of the different types of data into a single point set are discussed.

Automatic Coordinate Measuring Machine Inspection

1999 ◽  
Author(s):  
V. A. Albuquerque ◽  
F. W. Liou ◽  
S. Agarwal ◽  
O. R. Mitchell
Keyword(s):  
Path Planning ◽  
Computer Aided Design ◽  
Coordinate Measuring Machine ◽  
Industrial Applications ◽  
Prototype Development ◽  
Development Cycle ◽  
Inspection Process ◽  
Measuring Machine ◽  
Aided Design ◽  
Point Placement

Abstract In many industrial applications, such as product prototype development, automation of inspection process can greatly improve product quality and product development cycle, time. This paper discusses a development of a vision aided automatic inspection using Coordinate Measuring Machine (CMM). We seek to integrate the flexibility afforded by computer vision systems with the precision of numerically controlled coordinate measuring machines to achieve a fully automatic and reliable inspection of the industrial parts. The 3-D design information and part specification from computer-aided design file is used for inspection point placement and CMM path planning. The proposed system demonstrates that optimal collision-free inspection paths can be efficiently generated for geometrically complex parts consisting of multiply intersecting features. This is made possible by using iterative subdivision of surfaces for point placement coupled with, efficient 3-D collision avoidance and path planning. The paper discusses different algorithms used, and presents experimental results.

Experimental Investigations for Rapid Moulding Solution of Plastics Using Polyjet Printing

2011 ◽  
Vol 701 ◽  
pp. 15-20 ◽  
Author(s):  
Rupinder Singh ◽  
Varinderjit Singh
Keyword(s):  
Plastic Material ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Point Of View ◽  
Experimental Investigations ◽  
Support Material ◽  
Economic Point ◽  
Measuring Machine ◽  
Plastic Components ◽  
Polyjet Printing

Rapid prototyping (RP) has been in evidence for the past twenty years and is being widely used in diverse areas, from the building of aesthetic and functional prototypes to the production of tools and moulds for technological prototypes. The purpose of the present study is to experimentally investigate the rapid moulding (RM) solutions for plastic components using polyjet printing (PP) technique. Starting from the identification of component/benchmark, prototypes with three different type of plastic material were produced, at different orientation and support material. Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the plastic components produced. Some important mechanical properties were also compared to verify the suitability of the components. The study highlighted the best orientation, support material quantity and type of plastic material for the selected component from dimensional accuracy and economic point of view as RM solution for plastic components. This process ensures rapid production of pre-series technological prototypes and proof of concept at less production cost and time.

scholarly journals Trueness and Precision of Three-Dimensional Digitizing Intraoral Devices

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Hussam Mutwalli ◽  
Michael Braian ◽  
Deyar Mahmood ◽  
Christel Larsson
Keyword(s):  
Three Dimensional ◽  
Coordinate Measuring Machine ◽  
In Vitro Study ◽  
Vitro Study ◽  
Distance Measurements ◽  
True Value ◽  
Measuring Machine ◽  
One Way Anova ◽  
Intraoral Devices

Aim. To measure the trueness and precision under repeatable conditions for different intraoral scanners (IOSs) when scanning fully edentulous arch with multiple implants. Materials and Methods. Three IOSs and one industrial scanner were used to scan one edentulous master cast containing five implant scan bodies and three spheres. The cast was scanned thirty times with each scanner device. All scans were analyzed in the inspect software, and three-dimensional locations of the implants and the interarch distance between the spheres were measured. The values were compared to measurements made with one coordinate measuring machine (true value). One-way ANOVA was used to calculate the differences between IOSs and in comparison with the true value. Results. Significant differences were found between all IOSs. For the implant measurements, Trios 3 had the lowest trueness (≤114 μm), followed by Trios 3 mono (≤63 μm) and Itero element (≤−41 μm). Trios had the lowest precision (≤135 μm), followed by Itero element (≤101 μm) and Trios 3 mono (≤100 μm). With regard to the interarch distance measurements, Trios 3 had the lowest trueness (≤68 μm), followed by Trios 3 mono (≤45 μm) and Itero element (≤40 μm). Trios 3 had the lowest precision (≤206 μm), followed by Itero element (≤124 μm) and Trios 3 mono (≤111 μm). Conclusion. The results from this in vitro study suggest that precision is low for the tested IOS devices when scanning fully edentulous arches with multiple implants.

scholarly journals Linear Accuracy of Full-Arch Digital Models Using Four Different Scanning Methods: An In Vitro Study Using a Coordinate Measuring Machine

2020 ◽  
Vol 10 (8) ◽  
pp. 2741 ◽  
Author(s):  
Young Hyun Kim ◽  
Sang-Sun Han ◽  
Yoon Joo Choi ◽  
Chang-Woo Woo
Keyword(s):  
Coordinate Measuring Machine ◽  
In Vitro Study ◽  
Dental Arch ◽  
Accuracy Evaluation ◽  
Arch Model ◽  
Linear Measurements ◽  
Scanning Method ◽  
True Model ◽  
Measuring Machine

Improving the accuracy of the digital model is essential for the digitalization of the dental field. This study introduced a novel method of objective accuracy evaluation of digitized full dental arch model using coordinate measuring machine (CMM). To obtain a true linear measurement value using the CMM, 17 reference balls were attached to the typodont, and 12 measurements between balls on the X-(width), Y-(length), and Z-axes (height) were performed automatically. A rubber impression and a plaster cast replica of the typodont with balls were fabricated, and they were digitized with following methods: (a) true model intraoral scans; (b) impression cone-beam computed tomography (CBCT) scans; (c) cast CBCT scans; and (d) cast extraoral scans. Each scanning method was performed 20 times. Twelve linear measurements on the digitized models were automatically made using software. The one-sample t-test and one-way analysis of variance were used for measurement accuracy analysis. The cast extraoral scan was most accurate on X- and Y-axes, while impression CBCT was the most accurate on Z-axis. Over all axes, the intraoral scan resulted in the most deviation from the true model, and the reproducibility of each scan was also low. Extraoral scan shows high precision on width and length, and impression CBCT is advantageous for dental work where height factor is of importance.

scholarly journals Characterization of machining quality attributes based on spindle probe, coordinate measuring machine, and surface roughness data

2014 ◽  
Vol 1 (2) ◽  
pp. 128-139 ◽  
Author(s):  
Tzu-Liang Bill Tseng ◽  
Yongjin James Kwon
Keyword(s):  
Surface Roughness ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Quality Characteristics ◽  
Machining Parameters ◽  
Production Environment ◽  
Significant Interaction Effect ◽  
Machining Quality ◽  
Measuring Machine ◽  
Touch Probe

Abstract This study investigates the effects of machining parameters as they relate to the quality characteristics of machined features. Two most important quality characteristics are set as the dimensional accuracy and the surface roughness. Before any newly acquired machine tool is put to use for production, it is important to test the machine in a systematic way to find out how different parameter settings affect machining quality. The empirical verification was made by conducting a Design of Experiment (DOE) with 3 levels and 3 factors on a state-of-the-art Cincinnati Hawk Arrow 750 Vertical Machining Center (VMC). Data analysis revealed that the significant factor was the Hardness of the material and the significant interaction effect was the Hardness + Feed for dimensional accuracy, while the significant factor was Speed for surface roughness. Since the equally important thing is the capability of the instruments from which the quality characteristics are being measured, a comparison was made between the VMC touch probe readings and the measurements from a Mitutoyo coordinate measuring machine (CMM) on bore diameters. A machine mounted touch probe has gained a wide acceptance in recent years, as it is more suitable for the modern manufacturing environment. The data vindicated that the VMC touch probe has the capability that is suitable for the production environment. The test results can be incorporated in the process plan to help maintain the machining quality in the subsequent runs.

Experimental Investigations for Statistically Controlled Rapid Moulding Solution of Plastics Using Polyjet Printing

2010 ◽  
Author(s):  
Rupinder Singh ◽  
Varinderjit Singh ◽  
Manohar Singh Saini
Keyword(s):  
Plastic Material ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Point Of View ◽  
Experimental Investigations ◽  
Economic Point ◽  
The Past ◽  
Measuring Machine ◽  
Plastic Components ◽  
Polyjet Printing

Rapid prototyping (RP) has been in evidence for the past twenty years and is being widely used in diverse areas, from the building of aesthetic and functional prototypes to the production of tools and moulds for technological prototypes. The purpose of the present study is to experimentally investigate statistically controlled rapid moulding (RM) solutions for plastic components using polyjet printing (PP). Starting from the identification of component/benchmark, prototypes with three different type of plastic material were prepared, at different orientations. Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the components prepared. Some important mechanical properties were also compared to verify the suitability of the components. The study highlighted the best orientation, support material quantity and type of plastic material for the selected component from dimensional accuracy and economic point of view as RM solution for plastic components. Final components prepared are acceptable as per ISO standard UNI EN 20286-I (1995). This process ensures rapid production of statistically controlled pre-series technological prototypes and proof of concept at less production cost and time.

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