Porosity and accuracy of multiple-unit titanium castings

Chai, Tsongi; Stein, R. Sheldon

doi:10.1016/s0022-3913(05)80112-x

Cited by 47 publications

(22 citation statements)

References 20 publications

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“…As with the monoceramic crowns, the ceramic ingots used for pressureforming were also industrially manufactured, and thus it is difficult to suppose that the ceramic ingots contained lots of pores. Therefore, it was likely that the pores in the heat-pressed crown were caused during the laboratory work, when heat forming was performed as with titanium castings 19) . There were almost no pores in the ceramic core of the crown fabricated by a CAD/CAM system, but there were pores in the porcelain veneer.…”

Section: Discussionmentioning

confidence: 99%

Analysis of Internal Defects in All-ceramic Crowns Using Micro-focus X-ray Computed Tomography

et al. 2007

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Section: Discussionmentioning

confidence: 99%

Analysis of Internal Defects in All-ceramic Crowns Using Micro-focus X-ray Computed Tomography

et al. 2007

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“…Traditionally hit-and-run methods were used to improve the casting design because ''sprue is an art which is not well understood [12] ". ''The various commonly used sprue designs have been found to be inadequate with casting titanium because of the low density of the metal, and sprue attachment geometry may produce different castability and porosity effects for lower density metals [6] ". With the simulation method the shrinkage porosity can be well predicted, and easily controlled by optimizing the casting design.…”

Section: Discussionmentioning

confidence: 99%

“…Titanium is relatively difficult to cast. One of the most commonly occurred casting defects is porosity, which drew much attention in the last few years [4][5][6][7] . A preliminary study [8,9] indicated that the casting process of the titanium prostheses, including mold filling, solidification and even the accompanying porosity can be simulated numerically.…”

Section: Introductionmentioning

confidence: 99%

Dental Prostheses Produced by Integration of Laser Digitizing, Numerical Simulation, Rapid Prototyping into Investment Casting Process

Wagner

Sahm

et al. 2000

Materials for Medical Engineering

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The integration of laser measuring, numerical simulation and rapid-prototyping (RP) into investment casting process proposes a new way for making dental prostheses.Natural tooth crowns were precisely digitized by means of laser measuring technique. The digitized geometry was converted to a standard CAD model. This model was then used to simulate the mold filling, the solidification and the porosity formation etc., hence to improve and ensure the casting quality. The sprue system design was numerically optimized.Real crowns were 'printed' directly out on a RP system from the CAD data. The RP crowns were assembled to the optimized sprue system. Following the investment casting process, titanium crowns with excellent functional contour of the occlusal surface were successfully made on a centrifugal casting machine. For each crown, over 20 replicas were made. All of them were examined by radiograph and no porosity was detected.It is indicated that the traditional waxing procedure in dental laboratory is probably replaced by an integrated RP technique. The quality of the prostheses can be optimized numerically.

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“…Various factors influence the castability of a metal, such as alloy composition 19 , investment type 11,18 , sprue design [20][21][22] , casting temperature 19 , type of casting machine 23 , surface tension of the alloy, and the direction of force during casting 18 . In this study, centrifugation may have influenced the castability test.…”

Section: Castabilitymentioning

confidence: 99%

Influence of investment granulometry on the castability and surface roughness of castings obtained with Ni/Cr alloys

et al. 2009

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The aim of this study was to verify the influence of investment granulometry on the castability and surface roughness of Ni/Cr castings. Four investments were selected for casting according to decreasing order of granulometry: Heat Shock > Micro Fine 1700 > Gilvest HS > Castotal. Castability was verified by means of 40 specimens made with a polyester screen and determined from the number of segments completely filled by the cast alloy. To analyze the roughness, 40 disk-shaped wax patterns were made (15 x 3 mm), and after inclusion in the investments, they were cast and analyzed, before and after polishing (Mitutoyo SJ-201). The measurements were statistically analyzed (1-ANOVA -Tukey -p < 0.05) and it was verified that Heat Shock provided the worst castability with significant difference (p < 0.05) when compared with other investments. This material and Castotal presented similar roughness before and after polishing, with statistically significant difference (p < 0.05) between them and Gilvest and Micro Fine. It was concluded that investments with smaller granulometry provided castings that were more complete, but not smoother.

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Porosity and accuracy of multiple-unit titanium castings

Cited by 47 publications

References 20 publications

Analysis of Internal Defects in All-ceramic Crowns Using Micro-focus X-ray Computed Tomography

Analysis of Internal Defects in All-ceramic Crowns Using Micro-focus X-ray Computed Tomography

Dental Prostheses Produced by Integration of Laser Digitizing, Numerical Simulation, Rapid Prototyping into Investment Casting Process

Influence of investment granulometry on the castability and surface roughness of castings obtained with Ni/Cr alloys

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