Direct mechanical data acquisition of dental impressions for the manufacturing of CAD/CAM restorations

Quaas, Sebastian; Rudolph, Heike; Luthardt, Ralph G.

doi:10.1016/j.jdent.2007.08.008

Cited by 108 publications

(85 citation statements)

References 12 publications

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“…Therefore a certain area, the lowest 10% and the highest 10% of the difference values is not taken for comparisons. Yet with 80 percent of the scanned surface, the difference analysis represents more model surface than a mean value with root mean square deviation that only consists of 66% of the measured differences, a value which mainly was used in other studies (Luthardt et al, 2003) (Quaas et al, 2007). Other studies use the accuracy of the final restoration for evaluation the impression technique (Syrek et al, 2010)(Del'Acqua, Arioli-Filho, Compagnoni, & Mollo Fde, 2008).…”

Section: Digital Impressionmentioning

confidence: 99%

“…It is possible to measure surfaces points with high trueness with CMM machines. But these methods are lacking scan speed and the restriction of measuring freeform surfaces like fissure lines and interproximal areas because of the geometrical size of the tipball (Quaas, Rudolph, & Luthardt, 2007) (Delong, Heinzen, Hodges, Ko, & Douglas, 2003). Optical scanners with high accuracy are currently limited to small measurement fields like single teeth or quadrants (Luthardt, Kuhmstedt, & Walter, 2003) (Mehl, Ender, Mörmann, & Attin, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Accuracy of complete-arch dental impressions: A new method of measuring trueness and precision

Ender

Mehl

2013

The Journal of Prosthetic Dentistry

471

434

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STATEMENT OF PROBLEM: A new approach to both 3-dimensional (3D) trueness and precision is necessary to assess the accuracy of intraoral digital impressions and compare them to conventionally acquired impressions. PURPOSE: The purpose of this in vitro study was to evaluate whether a new reference scanner is capable of measuring conventional and digital intraoral complete-arch impressions for 3D accuracy. MATERIAL AND METHODS: A steel reference dentate model was fabricated and measured with a reference scanner (digital reference model). Conventional impressions were made from the reference model, poured with Type IV dental stone, scanned with the reference scanner, and exported as digital models. Additionally, digital impressions of the reference model were made and the digital models were exported. Precision was measured by superimposing the digital models within each group. Superimposing the digital models on the digital reference model assessed the trueness of each impression method. Statistical significance was assessed with an independent sample t test (=.05). RE-SULTS: The reference scanner delivered high accuracy over the entire dental arch with a precision of 1.6 ±0.6 µm and a trueness of 5.3 ±1.1 µm. Conventional impressions showed significantly higher precision (12.5 ±2.5 µm) and trueness values (20.4 ±2.2 µm) with small deviations in the second molar region (P<.001). Digital impressions were significantly less accurate with a precision of 32.4 ±9.6 µm and a trueness of 58.6 ±15.8µm (P<.001). More systematic deviations of the digital models were visible across the entire dental arch. CONCLUSIONS: The new reference scanner is capable of measuring the precision and trueness of both digital and conventional complete-arch impressions. The digital impression is less accurate and shows a different pattern of deviation than the conventional impression. Methods: A steel reference model was scanned with the reference scanner to evaluate precision and trueness. The reference model then was used to perform five conventional impressions with a polyvinylsiloxanether material (Identium, Kettenbach) in a putty and wash technique with standard stock trays (ASA Permalock, ASA Dental). The conventional impressions were poured with Type IV stone (CamBase, Dentona) and scanned with the reference scanner. Five digital impressions with a optical intraoral scanning system (CEREC AC, Sirona) were made. In each group, the models were superimposed and the differences computed with a signed nearest neighbour method. The 90-10%/2 percentile of the differences from each comparison was taken to compute the mean value for precision. The trueness of each impression method was assessed through superimposition of the impressions with the refefence scan of the steel reference model. Results:The reference scanner delivers an accuracy with 1.6±0.6 µm for precision and 5.3±1.1 µm for trueness over a full dental arch scan. The conventional impression method shows significant higher (p<0.001) precision (12.5±2.5 µm) and trueness (20....

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Section: Digital Impressionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Accuracy of complete-arch dental impressions: A new method of measuring trueness and precision

Ender

Mehl

2013

The Journal of Prosthetic Dentistry

471

434

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“…18,26,[38][39][40] Recently, a highly accurate method has been established for measuring the dental morphology of in vitro complete-arch impressions in clinical practice. 12,41 It uses a specially adapted highly accurate scanning protocol to measure complete-arch geometry. This method is able to compare conventional and digital impressions generated from the same geometry.…”

Section: Introductionmentioning

confidence: 99%

In vivo precision of conventional and digital methods of obtaining complete-arch dental impressions

Ender

Attin

Mehl

2016

The Journal of Prosthetic Dentistry

389

437

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STATEMENT OF PROBLEM: Digital impression systems have undergone significant development in recent years, but few studies have investigated the accuracy of the technique in vivo, particularly compared with conventional impression techniques. PURPOSE: The purpose of this in vivo study was to investigate the precision of conventional and digital methods for complete-arch impressions. MA-TERIAL AND METHODS: Complete-arch impressions were obtained using 5 conventional (polyether, POE; vinylsiloxanether, VSE; direct scannable vinylsiloxanether, VSES; digitized scannable vinylsiloxanether, VSES-D; and irreversible hydrocolloid, ALG) and 7 digital (CEREC Bluecam, CER; CEREC Omnicam, OC; Cadent iTero, ITE; Lava COS, LAV; Lava True Definition Scanner, T-Def; 3Shape Trios, TRI; and 3Shape Trios Color, TRC) techniques. Impressions were made 3 times each in 5 participants (n=15). The impressions were then compared within and between the test groups. The cast surfaces were measured point-to-point using the signed nearest neighbor method. Precision was calculated from the (90%-10%)/2 percentile value. RESULTS: The precision ranged from 12.3 m (VSE) to 167.2 m (ALG), with the highest precision in the VSE and VSES groups. The deviation pattern varied distinctly according to the impression method. Conventional impressions showed the highest accuracy across the complete dental arch in all groups, except for the ALG group. CONCLUSIONS: Conventional and digital impression methods differ significantly in the complete-arch accuracy. Digital impression systems had higher local deviations within the complete arch cast; however, they achieve equal and higher precision than some conventional impression materials. techniques. Impressions were made 3 times each in 5 participants (n = 15). The impressions were then compared within and between the test groups. The cast surfaces were measured point-to-point using the signed nearest neighbor method. Precision was calculated from the (90%-10%)/2 percentile value.Results. The precision ranged from 12.3 µm (VSE) to 167.2 µm (ALG), with the highest precision in the VSE and VSES groups. The deviation pattern varied distinctly according to the impression method. Conventional impressions showed the highest accuracy across the complete dental arch in all groups, except for the ALG group.Conclusions. Conventional and digital impression methods differ significantly in the complete-arch accuracy. Digital impression systems had higher local deviations within the 2 complete arch cast; however, they achieve equal and higher precision than some conventional impression materials. CLINICAL IMPLICATIONSThe accuracy of complete-arch impression casts differs significantly between conventional techniques and digital impression systems. Local deviations are greater in casts generated using digital impression systems; however, digital systems show adequate accuracy across the complete arch. As digital impression systems continue to improve, they may prove to be an equivalent or better alternative to convent...

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“…Conventional prosthetic fabrication methods require the establishment of a model by pouring stone into an impression from a patient. However, this method is neither cost-effective nor rapid 3) . To overcome these limitations, intraoral scanners have been used to create models for prostheses fabrication; however, this scanning method has not been reported to have high repeatability of results 4,5) .…”

Section: Introductionmentioning

confidence: 99%

“…To overcome these limitations, intraoral scanners have been used to create models for prostheses fabrication; however, this scanning method has not been reported to have high repeatability of results 4,5) . For these reasons, the development of reliable methods to obtain threedimensional impressions of a patient's oral structures using an extraoral scanner is increasingly important [3][4][5][6] . Scanning a stone model using an extraoral scanner is a common approach, and previous studies have shown a higher repeatability of stone model scanning than that of impression scanning 1,3,7) .…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional evaluation of the repeatability of scans of stone models and impressions using a blue LED scanner

et al. 2015

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In this study, we evaluated the repeatability of scans of stone models and impressions of abutment teeth using a blue LED scanner and compared the findings between different abutment teeth types. For the stone models as well as impression of the canines, premolars, and molars, we generated 10 color-difference-maps and reports for each tooth type (n=10 per tooth type). One-way analysis of variance (ANOVA) and independent t-tests were performed to evaluate the repeatability of scans of the stone models and impressions obtained from a blue LED scanner. Our results indicate a high repeatability of scans of stone models and impressions of abutment teeth using the blue LED scanner and suggest a possible clinical advantage for scanning impressions of different abutment teeth types.

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Direct mechanical data acquisition of dental impressions for the manufacturing of CAD/CAM restorations

Cited by 108 publications

References 12 publications

Accuracy of complete-arch dental impressions: A new method of measuring trueness and precision

Accuracy of complete-arch dental impressions: A new method of measuring trueness and precision

In vivo precision of conventional and digital methods of obtaining complete-arch dental impressions

Three-dimensional evaluation of the repeatability of scans of stone models and impressions using a blue LED scanner

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