scholarly journals Accuracy of optical scanning methods of the Cerec®3D system in the process of making ceramic inlays

2010 ◽  
Vol 67 (10) ◽  
pp. 812-818 ◽  
Author(s):  
Branka Trifkovic ◽  
Aleksandar Todorovic ◽  
Vojkan Lazic ◽  
Miroslav Draganjac ◽  
Nemanja Mirkovic ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Technological Development ◽  
Control Group ◽  
Gap Size ◽  
Marginal Gap ◽  
Optical Scanning ◽  
3D Cad ◽  
Ceramic Inlays ◽  
Cad Cam ◽  
Cerec 3D

Background/Aim. One of the results of many years of Cerec? 3D CAD/CAM system technological development is implementation of one intraoral and two extraoral optical scanning methods which, depending on the current indications, are applied in making fixed restorations. The aim of this study was to determine the degree of precision of optical scanning methods by the use of the Cerec?3D CAD/CAM system in the process of making ceramic inlays. Methods. The study was conducted in three experimental groups of inlays prepared using the procedure of three methods of scanning Cerec ?3D system. Ceramic inlays made by conventional methodology were the control group. The accuracy of optical scanning methods of the Cerec?3D system computer aided designcomputer aided manufacturing (CAD/CAM) was indirectly examined by measuring a marginal gap size between inlays and demarcation preparation by scanning electron microscope (SEM). Results. The results of the study showed a difference in the accuracy of the existing methods of scanning dental CAD/CAM systems. The highest level of accuracy was achieved by the extraoral optical superficial scanning technique. The value of marginal gap size inlays made with the technique of extraoral optical superficial scanning was 32.97 ? 13.17 ?. Techniques of intraoral optical superficial and extraoral point laser scanning showed a lower level of accuracy (40.29 ? 21.46 ? for inlays of intraoral optical superficial scanning and 99.67 ? 37.25 ? for inlays of extraoral point laser scanning). Conclusion. Optical scanning methods in dental CAM/CAM technologies are precise methods of digitizing the spatial models; application of extraoral optical scanning methods provides the hightest precision.

scholarly journals Influence of Material Selection on the Marginal Accuracy of CAD/CAM-Fabricated Metal- and All-Ceramic Single Crown Copings

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Matthias Rödiger ◽  
Lea Schneider ◽  
Sven Rinke
Keyword(s):  
Material Selection ◽  
Design Parameters ◽  
Processing Route ◽  
Chromium Alloy ◽  
Gap Size ◽  
Marginal Gap ◽  
Average Maximum ◽  
Single Crown ◽  
Cad Cam ◽  
Group 2

This study evaluated the marginal accuracy of CAD/CAM-fabricated crown copings from four different materials within the same processing route. Twenty stone replicas of a metallic master die (prepared upper premolar) were scanned and divided into two groups. Group 1 (n=10) was used for a pilot test to determine the design parameters for best marginal accuracy. Group 2 (n=10) was used to fabricate 10 specimens from the following materials with one identical CAD/CAM system (GAMMA 202, Wissner GmbH, Goettingen, Germany): A = commercially pure (cp) titanium, B = cobalt-chromium alloy, C = yttria-stabilized zirconia (YSZ), and D = leucite-reinforced glass-ceramics. Copings from group 2 were evaluated for the mean marginal gap size (MeanMG) and average maximum marginal gap size (AMaxMG) with a light microscope in the “as-machined” state. The effect of the material on the marginal accuracy was analyzed by multiple pairwise comparisons (Mann–Whitney, U-test, α=0.05, adjusted by Bonferroni-Holmes method). MeanMG values were as follows: A: 46.92 ± 23.12 μm, B: 48.37 ± 29.72 μm, C: 68.25 ± 28.54 μm, and D: 58.73 ± 21.15 μm. The differences in the MeanMG values proved to be significant for groups A/C (p=0.0024), A/D (p=0.008), and B/C (p=0.0332). AMaxMG values (A: 91.54 ± 23.39 μm, B: 96.86 ± 24.19 μm, C: 120.66 ± 32.75 μm, and D: 100.22 ± 10.83 μm) revealed no significant differences. The material had a significant impact on the marginal accuracy of CAD/CAM-fabricated copings.

scholarly journals Possible errors during the optical impression procedure

2010 ◽  
Vol 57 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Aleksandar Todorovic ◽  
Dejan Lisjak ◽  
Vojkan Lazic ◽  
Aleksandra Spadijer-Gostovic
Keyword(s):  
3D Cad ◽  
Dental Restorations ◽  
Study Results ◽  
Common Causes ◽  
Therapeutic Procedures ◽  
Causes Of Errors ◽  
Cad Cam ◽  
Optical Impression ◽  
Conventional Impression ◽  
Cerec 3D

Introduction. Modern technologies offer a range of benefits and significantly improve specific therapeutic procedures in dentistry. However, despite gaining experience and training there are still some mistakes in their implementation. The aim of this study was to describe the most common errors during intraoral scanning, 'optical impression' procedure, during CAD-CAM technology for production of dental restorations. Material and Methods. Cerec? 3D CAD-CAM system for one visit tooth reconstruction by inlays, onlays, endocrowns, half and complete crowns and veneers from the ceramic material was used in the study. Results. Analysis included 1564 reconstruction during 5 years. The most common causes of errors performing optical impression were the result of: improper preparation of teeth, the instability of the scanner in the mouth of the patient, incorrect position and angle of the scanner to the object scanning, contrast spray applied in uneven layer, the presence of fluid in the region scan, the presence of artifacts in the region gingival sulcus. Conclusion. Optical impression is faster procedure than conventional impression, but technologically sensitive. The most frequent errors are: improper handling of the scanner, inadequate tooth preparation, irregular powder application on the tooth and irregular use in the gingival sulcus.

scholarly journals Influence of Preparation Reconstruction on the Compressive Strength of CAD/CAM Ceramic Inlays

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Bruna Salamoni Sinhori ◽  
Luiz Clovis Cardoso Vieira ◽  
Luiz Narciso Baratieri
Keyword(s):  
Compressive Strength ◽  
Fracture Strength ◽  
Composite Resin ◽  
Resin Cement ◽  
Control Group ◽  
Tooth Structure ◽  
Ceramic Inlays ◽  
Compressive Strength Test ◽  
Cad Cam ◽  
Group 2

The aim of this study was to evaluate whether the compressive strength of lithium dissilicate ceramic inlays is influenced by the substrate (dentin or composite resin build-up) and to compare it to nonrestored teeth. Thirty freshly extracted human maxillary third molars were selected and randomly ascribed to three groups (n=10). Standardized Class II MOD preparations were made (bucco-palatal width = 2/3 of the intercuspal width and 2/3 of the width at the tooth equator for the proximal boxes), varying the extension of the preparations (Group 2: preparation limited to tooth structure; Group 3: pulpal floor of the preparation rebuilt with composite resin, IPS Empress Direct, restored with lithium dissilicate CAD/CAM ceramic inlays (e.max CAD) and cemented with a resin cement (Variolink II)). All groups were subjected to compressive strength test (1mm/min crosshead speed). The results showed that the fracture strength of G1 (control group) was significantly higher than G2 and G3, while within these groups there were no statistically significant differences. Both groups restored with lithium dissilicate restorations did not reach the fracture strength of the sound teeth but were statistically equivalent and sufficient to withstand physiologic masticatory forces.

Interface gap size of manually and CAD/CAM-manufactured ceramic inlays/onlays in vitro

2002 ◽  
Vol 30 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Simon Addi ◽  
Arjang Hedayati-Khams ◽  
Amin Poya ◽  
Göran Sjögren
Keyword(s):  
Gap Size ◽  
Ceramic Inlays ◽  
Cad Cam

scholarly journals INFLUENCE OF DIFFERENT SURFACE TREATMENTS OF CAD/CAM HYBRID NANOCERAMICS CROWNS ON BOND STRENGTH OF RESIN COMPOSITE CEMENT

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Valentina Veselinović ◽  
Rebeka Rudolf ◽  
Nataša Trtić ◽  
Verica Pavlić ◽  
Radmila Arbutina ◽  
...  
Keyword(s):  
Surface Modification ◽  
Hydrofluoric Acid ◽  
Technological Development ◽  
Resin Composite ◽  
Testing Machine ◽  
Resin Cement ◽  
Control Group ◽  
Retention Force ◽  
Group I ◽  
Cad Cam

Introduction: Urgent demand for high-esthetic material, which at the same time has the possibility of absorption of mastication stress, has led to the technological development of hybrid nanoceramics used in CAD / CAM technology. Aim: The aim of the study was to evaluate the effects of different surface modification of hybrid nanoceramic crowns on the quality of the cement retention and the influence of the mastication stress after one year of function. Material and methods: 50 hybrid nanoceramic CAD/CAM crowns (CERASMART, GC) are cemented on titanium implant abutments with self-adhesive resin cement (G-CEM, LinkAce). The samples were divided into five main groups according to surface treatment (n=10): I (sandblasted with 50 microns Al2O3), II (treated with CERAMIC PRIMER II, GC), III (treated with 5% hydrofluoric acid), IV (treated with combination of 5% hydrofluoric acid and CERAMIC PRIMER II), V (control, non-treated group). The samples were storaged during 24 hours at 37°C, thermocycled and loaded under 10 000 mechanical cycles loads (simulation of 12 months of function). Retention forces measured in Universal testing machine. The data were represented as mean ± standard deviation, and for statistical analysis ANOVA test was used. Results: The highest initial retention force was demonstrated in the group IV (6.99±1.18), followed by group I (6.22±1.29), group III (5,97±1,25), group II (5,86±1,17) and control group samples (4.92±1.19). A statistically significant decline in retention force was recorded in all tested groups, with the lowest decrease observed in samples treated with a combination of 5% hydrofluoric acid and CERAMIC PRIMER II (6.08 ± 1.03). Conclusion: Mechanical and chemical surface modification can strongly influence the retentions between resin cement and hybrid nanoceramics. The results from this study are suggesting that the most efficient clinical outcome is the combination of 5% hidrofluoric acid and CERAMIC PRIMER II.

Margin Gap Size of Ceramic Inlays Using Second-Generation CAD/CAM Equipment

1999 ◽  
Vol 11 (4) ◽  
pp. 206-214 ◽  
Author(s):  
JOHN R. STURDEVANT ◽  
STEPHEN C. BAYNE ◽  
HARALD O. HEYMANN
Keyword(s):  
Second Generation ◽  
Gap Size ◽  
Ceramic Inlays ◽  
Cad Cam

Marginal Fit of Implant-Supported All-Ceramic Zirconia Frameworks

2013 ◽  
Vol 39 (4) ◽  
pp. 417-424 ◽  
Author(s):  
Hanaa Hassan Zaghloul ◽  
Jihan Farouk Younis
Keyword(s):  
Cyclic Loading ◽  
Computer Aided Design ◽  
Control Group ◽  
Marginal Gap ◽  
Marginal Fit ◽  
Mean Values ◽  
Significant Difference ◽  
All Ceramic ◽  
Computer Aided ◽  
Cad Cam

This study evaluated the effect of fabrication techniques and cyclic loading on the vertical marginal fit of implant-supported fixed partial denture (FPD) frameworks. Thirty implant-supported 3-unit FPD frameworks were fabricated on a model system, divided into 3 equal groups (n = 10). The first group (control) was constructed from base metal alloy; the other 2 test groups were constructed from all-ceramic zirconia using a computer-aided design/computer-aided manufacturing (CAD/CAM) Cerec 3 system and a copy milling (Zirkonzahn) system. A cyclic load of 200 N was applied to each framework for up to 50,000 cycles. Linear measurements were made in micrometers of the vertical gap between the framework and the implant-supported abutment at 16 predetermined points before and after cyclic loading. The frameworks were viewed using scanning electron microscopy to inspect any fractographic features. One-way analysis of variance was performed to compare the marginal discrepancy values of the control and the 2 test groups and for each group; a t test was applied to determine whether significant changes in the fit were observed after cyclic loading (α = 0.05). The CAD/CAM group showed significantly higher marginal gap mean values (80.58 μm) than the Zirkonzahn and control groups (50.33 μm and 42.27 μm, respectively) with no significant difference. After cyclic loading, the CAD/CAM group recorded the highest marginal gap mean value (91.50 ± 4.260 μm) followed by control group (72.00 ± 2.795 μm); the Zirkonzahn group recorded the lowest marginal gap (65.37 ± 6.138 μm). Cyclic loading significantly increased the marginal gap mean values in the control group only. A marginal chip was observed in one of the CAD/CAM ceramic frameworks. Within the limitations of this study, the fabrication technique influenced the marginal fit of the implant-supported 3-unit FPD frameworks. Cyclic loading failed to change the fit of all-ceramic zirconia frameworks, whereas significant changes were found in the metal frameworks.

scholarly journals Marginal and Internal Fit of Ceramic Prostheses Fabricated from Different Chairside CAD/CAM Systems: An In Vitro Study

2021 ◽  
Vol 11 (2) ◽  
pp. 857
Author(s):  
Keunbada Son ◽  
Kyu-Bok Lee
Keyword(s):  
Computer Aided Design ◽  
In Vitro Study ◽  
Vitro Study ◽  
Marginal Gap ◽  
Significant Difference ◽  
Cad Cam ◽  
Ceramic Crowns ◽  
Internal Fit ◽  
Cam Systems

The purpose of this in vitro study was to evaluate marginal and internal fits of ceramic crowns fabricated with chairside computer-aided design and manufacturing (CAD/CAM) systems. An experimental model based on ISO 12836:2015 was digitally scanned with different intraoral scanners (Omnicam (CEREC), EZIS PO (DDS), and CS3500 (Carestream)). Ceramic crowns were fabricated using the CAD/CAM process recommended by each system (CEREC, EZIS, and Carestream systems; N = 15). The 3-dimensional (3D) marginal and internal fit of each ceramic crown was measured using a 3D inspection software (Geomagic control X). Differences among the systems and various measurements were evaluated using the Kruskal–Wallis test. Statistically significant differences were validated using pairwise comparisons (α = 0.05). Occlusal gaps in the CEREC, EZIS, and Carestream groups were 113.0, 161.3, and 438.2 µm, respectively (p < 0.001). The axial gaps were 83.4, 78.0, and 107.9 µm, respectively. The marginal gaps were 77.8, 99.3, and 60.6 µm, respectively, and the whole gaps were 85.9, 107.3, and 214.0 µm, respectively. Significant differences were observed with the EZIS system compared with the other two systems in terms of the marginal gap sizes. The CEREC system showed no significant differences among the four measured regions. However, the EZIS and Carestream systems did show a statistically significant difference (p < 0.05). All three systems were judged to be capable of fabricating clinically acceptable prostheses, because the marginal gap, which is the most important factor in the marginal fit of prostheses, was recorded to be below 100 µm in all three systems.

Optimization of Trapezoidal Runner in Plastic Molding Based on MATLAB

2014 ◽  
Vol 552 ◽  
pp. 66-69
Author(s):  
Gui Jie Fan
Keyword(s):  
Obtuse Angle ◽  
Minimum Length ◽  
Special Effects ◽  
Plastic Molding ◽  
Injection Speed ◽  
3D Cad ◽  
Section Area ◽  
Cad Cam ◽  
Mould Design ◽  
Runner Design

The runner design is an important parts in plastic molding design. Its shape and dimensions have special effects on the molten plastic’s pressure, hot loss, injection speed, etc. At present, trapezoidal runner is used widely for better fluidity and lower assembly precision relatively compared with the circular runner. This paper uses the Fminsearch function of MATLAB and constructs an objective function based on the minimum length of the perimeter of the trapezoidal runner to optimize the trapezoidal runner section. The conclusion of this paper is that the perimeter of the trapezoidal runner is the shortest one when a equals c (shown as Fig.1), as well as the obtuse angle between a and c equals 120o. At this conditions, the volume of the molten plastic that flows through the runner section is maximum when the trapezoidal runner section area is given. The optimization results in the plastic mould design can used as the size or the constraints to drive the runner section in 3D CAD/CAM software, which can help the designer to get the trapezoidal runner section easily and quickly.

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