scholarly journals Comparative Study of the Fit Accuracy of Full-Arch Bar Frameworks Fabricated with Different Presintered Cobalt-Chromium Alloys

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hang-Nga Mai ◽  
Tae-Yub Kwon ◽  
Min-Ho Hong ◽  
Du-Hyeong Lee
Keyword(s):  
Comparative Study ◽  
Machining Process ◽  
Mean Square ◽  
Cobalt Chromium ◽  
Arch Bar ◽  
Chromium Alloys ◽  
Structured Light Scanner ◽  
Reference Design ◽  
Soft Metal ◽  
Geometric Discrepancy

Purpose. This study was to measure the geometric discrepancies that occur during the sintering contraction of presintered Co-Cr alloys in a full-arch bar framework and to compare the variations between alloys from different manufacturers. Materials and Methods. Eighteen implant-supported full-arch bar frameworks were fabricated through a soft-machining process using presintered Co-Cr alloy blocks: Ceramill Sintron (CS), Soft Metal (SM), and Sintermetall (SML) (n=6 for each group). The sintered frameworks were digitized using a structured light scanner, and the scan images were superimposed on the reference design. The geometric discrepancies of the sintered frameworks were three-dimensionally analyzed for horizontal, angular, and internal discrepancies. Kruskal-Wallis and Mann–Whitney U tests were used to compare the discrepancies among the groups (α=.05). Results. Significant differences were found in the geometric discrepancy measurements among the groups. The CS group showed larger horizontal and angular discrepancies, followed by the SM and SML groups (P<.001). The root mean square (RMS) values for internal discrepancy were not statistically different among the groups (P=.778). Conclusion. The geometric discrepancies of full-arch bar frameworks fabricated using the soft-machining process were affected by accuracies in sintering contraction of presintered alloys.

Processing Development and Properties of Cobalt-Chromium Alloys Fabricated by Traditional Method

2021 ◽  
Vol 43 ◽  
pp. 2629-2634
Author(s):  
Wanwilai Vittayakorn ◽  
Phieraya Poolphol ◽  
Kantapon Aimprakod ◽  
Tosapol Maluangnont
Keyword(s):  
Traditional Method ◽  
Cobalt Chromium ◽  
Chromium Alloys

Retentive Forces of Removable Partial Denture Clasp Assemblies Made From Polyaryletherketone and Cobalt‐Chromium: A Comparative Study

2021 ◽  
Author(s):  
Frank I. Gentz ◽  
Daniel I. Brooks ◽  
Peter C. Liacouras ◽  
Anton Petrich ◽  
Christopher M. Hamlin ◽  
...  
Keyword(s):  
Comparative Study ◽  
Cobalt Chromium ◽  
Removable Partial Denture ◽  
Partial Denture

scholarly journals Effect of Digital Technologies on the Marginal Accuracy of Conventional and Cantilever Co–Cr Posterior-Fixed Partial Dentures Frameworks

2021 ◽  
Vol 11 (7) ◽  
pp. 2988
Author(s):  
Celia Tobar ◽  
Verónica Rodríguez ◽  
Carlos Lopez-Suarez ◽  
Jesús Peláez ◽  
Jorge Cortés-Bretón Brinckmann ◽  
...  
Keyword(s):  
Digital Technologies ◽  
Hard Metal ◽  
Direct Metal Laser Sintering ◽  
Cobalt Chromium ◽  
Metal Ceramic ◽  
Marginal Discrepancy ◽  
Soft Metal ◽  
Manufacturing Techniques ◽  
Ceramic Restorations ◽  
To Receive

The introduction of new digital technologies represents an important advance to fabricate metal–ceramic restorations. However, few studies have evaluated the influence of these technologies on the fit of the restorations. The aim of this study was to evaluate the effect of different manufacturing techniques and pontic design on the vertical marginal fit of cobalt–-chromium (Co–Cr) posterior fixed partial dentures (FPDs) frameworks. Methods: Eighty stainless-steel dies were prepared to receive 3-unit FPDs frameworks with intermediate pontic (n = 40) and cantilever pontic (n = 40). Within each design, the specimens were randomly divided into four groups (n = 10 each) depending on the manufacturing technique: casting (CM), direct metal laser sintering (LS), soft metal milling (SM), and hard metal milling (HM). The frameworks were luted, and the vertical marginal discrepancy was assessed. Data analysis was made using Kruskal–Wallis and Mann–Whitney U tests (α = 0.05). Results: The vertical marginal discrepancy values of all FPDs were below 50 μm. The HM frameworks obtained the lowest misfit values in both designs. However, no differences were found among intermediate pontic groups or cantilevered groups. Likewise, when differences in a marginal discrepancy between both framework designs were analyzed, no differences were observed. Conclusions: The analyzed digital technologies demonstrated high precision of fit on Co–Cr frameworks and on both pontic designs.

Influence of loading rates on mechanical properties of cobalt-chromium alloys

BDJ ◽  
1975 ◽  
Vol 138 (8) ◽  
pp. 295-298 ◽  
Author(s):  
M H Reisbick ◽  
A A Caputo
Keyword(s):  
Mechanical Properties ◽  
Cobalt Chromium ◽  
Loading Rates ◽  
Chromium Alloys

Method of Assessment of Casting Accuracy and Minimization of Machining Allowances

2012 ◽  
Author(s):  
Andrzej Gessner ◽  
Roman Staniek
Keyword(s):  
Machine Tool ◽  
Accuracy Assessment ◽  
Assessment Method ◽  
Machining Process ◽  
Shape Accuracy ◽  
Construction Design ◽  
Optical Scanner ◽  
Course Of Action ◽  
Reference Design ◽  
Method Of Assessment

The publication demonstrates an accuracy assessment method for machine tool body casting utilizing an optical scanner and a reference design of the machine tool body. The process allows assessing the casting shape accuracy, as well as determining whether the size of the allowances of all work surfaces is sufficient for appropriate machining, corresponding to the construction design. The described method allows dispensing with the arduous manual operation - marking out. Marking out, depending on the size and complexity, might take several working shifts for prototype casting. In case of large and elaborate casts, as those of machine tool bodies, marking out is often restricted only to the first cast of the desired body produced in a given casting mold. Such course of action is based on an assumption that casting is reproducible; hence, no need to assess each and every individual cast. While this approach saves time, it often results in late detection of casting errors (allowance shifts or insufficiencies) during the actual machining process. That, in turn, results in considerable losses due to the disruption of the work process and often demands cast repair. The aim of the hereby presented study is to introduce a new technological premise dispensing with manual marking out as well as allowing fast verification of the cast shapes.

Cobalt-chromium alloys in dentistry: An evaluation of metal ion release

2015 ◽  
Vol 114 (4) ◽  
pp. 602-608 ◽  
Author(s):  
Maria Claudia Lucchetti ◽  
Giovanni Fratto ◽  
Federica Valeriani ◽  
Elisabetta De Vittori ◽  
Saverio Giampaoli ◽  
...  
Keyword(s):  
Metal Ion ◽  
Cobalt Chromium ◽  
Ion Release ◽  
Chromium Alloys ◽  
Metal Ion Release

scholarly journals Cobalt-chromium alloys in fixed prosthodontics in Sweden

2017 ◽  
Vol 3 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Maria Kassapidou ◽  
Victoria Franke Stenport ◽  
Lars Hjalmarsson ◽  
Carina B. Johansson
Keyword(s):  
Cobalt Chromium ◽  
Fixed Prosthodontics ◽  
Chromium Alloys

scholarly journals Effect of recasting on the elastic modulus of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

2007 ◽  
Vol 64 (7) ◽  
pp. 469-473 ◽  
Author(s):  
Nemanja Mirkovic
Keyword(s):  
Elastic Modulus ◽  
Testing Machine ◽  
Fracture Load ◽  
Bending Test ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Nickel Chromium ◽  
Ceramic Samples ◽  
Chromium Alloys ◽  
Metal Ceramic

Background/Aim. Elastic modulus of metal-ceramic systems determines their flexural strength and prevents damages on ceramics during mastication. Recycling of basic alloys is often a clinical practice, despite the possible effects on the quality of the future metal-ceramic dentures. This research was done to establish recasting effects of nickel-chromium and cobalt-chromium alloys on the elastic modulus of metalceramic systems in making fixed partial dentures. Methods. The research was performed as an experimental study. Six metal-ceramic samples of nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C) were made. Alloy residues were recycled through twelve casting generations with the addition of 50% of new alloy on the occasion of every recasting. Three- point bending test was used to determine elastic modulus, recommended by the standard ISO 9693:1999. Fracture load for damaging ceramic layer was recorded on the universal testing machine (Zwick, type 1464), with the speed of 0,05 mm/min. Results. The results of this research revealed significant differences between elasticity modules of metal-ceramic samples in every examined recycle generation. Recasting had negative effect on the elastic modulus of the examined alloys. This research showed the slight linear reduction of elastic modulus up to the 6th generation of recycling. After the 6th recycling there was a sudden fall of elastic modulus. Conclusion. Recasting of nickelchromium and cobalt-chromium alloys is not recommended because of the reduced elastic modulus of these alloys. Instead of reusing previously recasted alloys, the alloy residues should be returned to the manufacturer. .

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